Saturday, November 27, 2010

JOURNAL FAULT LOCATION ON TRANSMISSION OVERHEAD LINE (ABSTRACT)

        1. Moghadas, A.A., Shadaram, M., 2010. Fiber Bragg Grating Sensor for Fault Detection in Radial and Network Transmission Lines. Sensors 10, 9407-9423.
Abstract: In this paper, a fiber optic based sensor capable of fault detection in both radial and network overhead transmission power line systems is investigated. Bragg wavelength shift is used to measure the fault current and detect fault in power systems. Magnetic fields generated by currents in the overhead transmission lines cause a strain in magnetostrictive material which is then detected by Fiber Bragg Grating (FBG). The Fiber Bragg interrogator senses the reflected FBG signals, and the Bragg wavelength shift is calculated and the signals are processed. A broadband light source in the control room scans the shift in the reflected signal. Any surge in the magnetic field relates to an increased fault current at a certain location. Also, fault location can be precisely defined with an artificial neural network (ANN) algorithm. This algorithm can be easily coordinated with other protective devices. It is shown that the faults in the overhead transmission line cause a detectable wavelength shift on the reflected signal of FBG and can be used to detect and classify different kind of faults. The proposed method has been extensively tested by simulation and results confirm that the proposed scheme is able to detect different kinds of fault in both radial and network system
      2.   Masoud, M.E., Mahfouz, M.M.A., 2010. Protection scheme for transmission lines based on alienation coefficients for current signals. Iet Generation Transmission & Distribution 4, 1236-1244.
Abstract: In modern digital power system protection systems, statistical coefficients technique is recently used for fault analysis. An alienation technique is developed for faults detection and discrimination. The proposed technique is able to accurately identify the condition of phase(s) involved in all ten types of shunt faults that may occur in extra high-voltage transmission lines under different fault resistances, inception angle and loading levels. The proposed technique does not need any extra equipment as it depends only on the three line-currents measurements which are mostly available at the relay location. This technique is able to perform the fault detection, type and phase selection in about a half-cycle period. Thus, the proposed technique is well suited for implementation in digital protection schemes. The proposed methodology is applied for a part of 500 KV Egyptian network. Alternative transient program and MATLAB programs are used to implement the proposed technique
      3.   Huang, X.H., Zhang, G.M., Xiao, L.Y., 2010. Optimal Location of SMES for Improving Power System Voltage Stability. Ieee Transactions on Applied Superconductivity 20, 1312-1315.
Abstract: Superconducting magnetic energy storage (SMES) system is an equipment that can help improving the stability of a power system. Location of SMES in multi-nodes power network plays a significant role for the stability improvement level. In this paper, based on the quantitative voltage stability index, genetic algorithm (GA) is used for optimization of the SMES location. The voltage stability index is used as the fitness function in GA. The GA mathematic parameters and optimal flow chart are presented. The proposed algorithm is tested in an IEEE 14-bus system. Simulation results show that the SMES is settled on the best site through GA optimization during the period of the voltage stability fault
      4.   Vahedi, H., Yazdani-Asrami, M., 2010. A New Diagnostic Test for Power Cables Based on Frequency Analysis. International Review of Electrical Engineering-Iree 5, 1784-1788.
Abstract: Electric power cables are considered as one of the essential elements in electric transmission and distribution systems. Any failure in these equipments directly reduces system reliability and increases maintenance costs. Consequently, the preventive maintenance techniques and also fault diagnosis methods are increasingly developed In this regard, frequency response analysis (ERA) can be taken to be account an appropriate method in order to diagnose any change which occurs in cables physical construction. This contribution has concentrated on the application of frequency analysis measurements as a new kind of diagnostic lest to investigate its ability for diagnosing a few numbers of common faults which are occurred in power cables. Experimental measurements have been performed on a power cable using ERA analyzer instrument in two healthy and faulty situations. All intentional faults have been experimentally applied on geometry of cables and the ERA results have been measured and compared The obtained results are very interesting and applicable for maintenance aims to find the happened fault, quickly. Copyright (C) 2010 Praise Worthy Prize S.r.l - All rights reserved
      5.   He, Z.Y., Fu, L., Lin, S., Bo, Z.Q., 2010. Fault Detection and Classification in EHV Transmission Line Based on Wavelet Singular Entropy. Ieee Transactions on Power Delivery 25, 2156-2163.
Abstract: A novel technique for fault detection and classification in the extremely high-voltage transmission line using the fault transients is proposed in this paper. The novel technique, called wavelet singular entropy (WSE), incorporates the advantages of the wavelet transform, singular value decomposition, and Shannon entropy. WSE is capable of being immune to the noise in the fault transient and not being affected by the transient magnitude so it can be used to extract features automatically from fault transients and express the fault features intuitively and quantitatively even in the case of high-noise and low-magnitude fault transients. The WSE-based fault detection is performed in this paper, which proves the availability and superiority of WSE technique in fault detection. A novel algorithm based on WSE is put forward for fault classification and it is verified to be effective and reliable under various fault conditions, such as fault type, fault inception time, fault resistance, and fault location. Therefore, the proposed WSE-based fault detection and classification is feasible and has great potential in practical applications
      6.   Apostolopoulos, C.A., Korres, G.N., 2010. A Novel Algorithm for Locating Faults on Transposed/Untransposed Transmission Lines Without Utilizing Line Parameters. Ieee Transactions on Power Delivery 25, 2328-2338.
Abstract: This paper puts forward a novel algorithm for locating faults on power transmission lines without requiring line parameters. The algorithm utilizes unsynchronized measurements of voltages and currents from both ends of a transmission line and is formulated in terms of the fundamental frequency phasors of the measured signals. Both prefault and postfault phasors are processed for determining the sought distance to fault and the synchronization angle. The calculations are performed initially for a lumped parameter line model with neglecting shunt capacitance. Then, these results are used as starting values for an iterative process, where the impacts of the shunt capacitance of the line are considered. The proposed two-stage fault-location algorithm is applicable for transposed and untransposed transmission lines and is independent of the fault resistance and source impedances. Evaluation studies using reliable Alternate Transients Program-Electromagentic Transients Program simulation data verify that the proposed algorithm can yield quite accurate results
      7.   Jovcic, D., Ooi, B.T., 2010. Developing DC Transmission Networks Using DC Transformers. Ieee Transactions on Power Delivery 25, 2535-2543.
Abstract: This paper studies principles of developing dc transmission grids based on high power dc/dc converters. There has been much research on dc/dc converters and it is likely that some megawatt size units will achieve commercialisation stage soon. In this study, we assume that electronic dc transformers can achieve three functions: 1) voltage stepping, 2) voltage (or power) regulation, and 3) fault isolation. The location, sizing, and control of dc transformers is first analyzed using a simple 4-terminal, 1.8GW dc grid. It is postulated that this grid would be a better alternative to a point-to-point HVDC. Detailed simulations on PSCAD/EMTDC demonstrate the capability to independently regulate power flow in each dc branch. The simulations of worst case faults on dc lines and ac grids show that dc transformers can isolate the faulted segments enabling the remaining part of the grid to operate normally. The generic principles of developing more complex dc grids with meshed power flows, are also presented. It is concluded that there are no significant technical barriers in developing dc transmission grids but the cost and losses of dc transformers remain as the primary challenges
      8.   Ferreira, K.J., Emanuel, A.E., 2010. A Noninvasive Technique for Fault Detection and Location. Ieee Transactions on Power Delivery 25, 3024-3034.
Abstract: Most methods of fault detection and location rely on measurements of electrical quantities provided by current and voltage transformers. These transformers require physical contact with the monitored high-voltage equipment. Moreover, during fault transients, the secondary current is not a true replica of the primary current. This paper explores the possibility of replacing current transformers with magnetic field sensing coils. These coils are located at the sending and receiving ends of the power lines, in the proximity of the conductors. Rather than monitoring the current in each individual phase conductor, magnetic field sensors allow transmission line monitoring by means of a single collective measurement. This study explores the use of the magnetic field sensors as alternative measurement devices for fault detection and location
      9.   Borghetti, A., Bosetti, M., Nucci, C.A., Paolone, M., Abur, A., 2010. Integrated Use of Time-Frequency Wavelet Decompositions for Fault Location in Distribution Networks: Theory and Experimental Validation. Ieee Transactions on Power Delivery 25, 3139-3146.
Abstract: The paper presents a procedure for fault location in distribution networks, based on the use of the integrated time-frequency wavelet decompositions of the voltage transients associated with the fault-originated travelling waves. The proposed analysis of time-frequency wavelet decompositions has been found to improve the identification accuracy of the frequencies associated to the characteristic patterns of a fault location with respect to a sole frequency-domain wavelet analysis. Several laboratory fault tests, carried out by means of a reduced-scale model of a distribution feeder, are used to illustrate the characteristics and assess the performances of the proposed improved procedure. The paper also illustrates the application of the proposed procedure to a transient, originated by a permanent phase-to-phase fault, measured in a real distribution network in which a post-test analysis has identified the faulted branch
    10.   Upendar, J., Gupta, C.P., Singh, G.K., Ramakrishna, G., 2010. PSO and ANN-based fault classification for protective relaying. Iet Generation Transmission & Distribution 4, 1197-1212.
Abstract: Fault classification in electric power system is vital for secure operation of power systems. It has to be accurate to facilitate quick repair of the system, improve system availability and reduce operating costs due to mal-operation of relay. Artificial neural networks (ANNs) can be an effective technique to help to predict the fault, when it is provided with characteristics of fault currents and the corresponding past decisions as outputs. This paper describes the use of particle swarm optimisation (PSO) for an effective training of ANN and the application of wavelet transforms for predicting the type of fault. Through wavelet analysis, faults are decomposed into a series of wavelet components, each of which is a time-domain signal that covers a specific octave frequency band. The parameters selected for fault classification are the detailed coefficients of all the phase current signals, measured at the sending end of a transmission line. The information is then fed into ANN for classifying the faults. The proposed PSO-based multi-layer perceptron neural network gives 99.91% fault classification accuracy. Moreover, it is capable of producing fast and more accurate results compared with the back-propagation ANN. Extensive simulation studies were carried out and a set of results taken from the simulation studies are presented in this paper. The proposed technique when combined with a wide-area monitoring system would be an effective tool for detecting and identifying the faults in any part of the system
    11.   Roy, D.S., Anil, A., Mohanta, D.K., Panda, A.K., 2010. Well-being Analysis of Safety Critical Software: A Case Study for Computer Relaying. Electric Power Components and Systems 38, 1299-1316.
Abstract: Assessment of software reliability has emerged as an area of utmost importance in recent times with the proliferation of software-based systems. Conventional software reliability assessment is done by applying software models that incorporate the unfortunate drawback of requiring previous failure data to formulate the model based on statistical methodologies. But highly dependable software systems used for safety-critical applications, such as computer relays for power system transmission line protection, produce little failure data. This article presents a methodology using statistics of extremes to embark upon software success estimation. The estimate so obtained is an indicator analogous to the conventional reliability index. This estimated reliability is further employed for assessing software's health more effectively by means of well-being analysis. The most significant contribution of this article is to compute the software well-being indices for healthy, marginal, and risky states. A case study for software used in computer relaying of power system transmission line protection validates the efficacy of the proposed methodology, especially for safety-critical applications
    12.   Mark, W.D., Lee, H., Patrick, R., Coker, J.D., 2010. A simple frequency-domain algorithm for early detection of damaged gear teeth. Mechanical Systems and Signal Processing 24, 2807-2823.
Abstract: Fixed transducers often are used to monitor meshing gear pairs in order to detect tooth damage A simple frequency-domain damage-detection algorithm is suggested for very early detection of such damage. Ratios of rotational-harmonic amplitudes computed from before and after potential damage are utilized to eliminate effects of transducer and structural-path-caused amplitude changes between tooth-meshing location and transducer output, to minimize attenuating effects of multiple-tooth contact, and thereby, to approximately equally weight rotational-harmonic amplitudes over a wide range of harmonics. Statistical averaging of absolute values of logarithmic ratios of rotational-harmonic amplitudes is used to minimize fluctuations caused by multiple-tooth contact and manufacturing errors on the subject gear. Synchronous averaging is employed to minimize effects of noise and manufacturing errors on the mating gear. Time-windowing tailored to contact ratios of mating gears is utilized to isolate individual tooth locations. Resultant windowing effects on availability of useful rotational harmonics are analyzed. Application of the algorithm to detection of seeded bending-fatigue faults on a planetary ring-gear tooth indicates that successful detections were achieved. (C) 2010 Elsevier Ltd. All rights reserved
    13.   Gayathri, K., Kumarappan, N., 2010. Accurate fault location on EHV lines using both RBF based support vector machine and SCALCG based neural network. Expert Systems with Applications 37, 8822-8830.
Abstract: An appropriate method for fault location on Extra High Voltage (EHV) transmission line using Support Vector Machine (SVM) is proposed in this paper. It relies on the application of SVM and frequency characteristics of the measured single end positive sequence voltage and current measurement of transient signals of the system. This paper is proposing a new hybrid approach for fault location on EHV lines using Radial Basis Function (RBF) basis SVM and Scaled Conjugate Gradient (SCALCG) basis neural network method. Sample inputs are determined by MATLAB. The average error of fault location in 400 kV and 150 km line is tested and the results prove that the proposed method is effective and reduce the error within a short duration of time using both RBF based SVM and SCALCG based neural network. (C) 2010 Elsevier Ltd. All rights reserved
    14.   Beiza, J., Hosseinian, S.H., Vahidi, B., 2010. Multiphase transmission line modeling for voltage sag estimation. Electrical Engineering 92, 99-109.
Abstract: This paper presents a novel approach for voltage sag indices calculation based on instantaneous voltage estimation. The estimation uses traditional state estimation where redundant measurements are available. The estimation is based on time domain state estimation which uses time domain modeling of the power network. The time domain current monitoring is used to have linear mapping and to achieve high performance of voltage sag estimation. The fault estimation procedure is prior of the voltage sag estimation. This paper shows a possible for fault instance detection, fault location identification and fault type estimation method that are required to estimate voltage sag for different line models utilizing residual analysis and topology error processing. Lumped parameter and distributed parameter transmission line modeling are developed to estimate instantaneous voltage at a three-phase power system in time domain. Magnitude and duration of voltage sag as main indices are calculated from the estimated instantaneous bus voltage. The performance of the novel approach is tested on IEEE 14 bus system and the results are shown
    15.   Eldin, E.M.T., 2010. Fault Location for a Series Compensated Transmission Line Based on Wavelet Transform and an Adaptive Neuro-Fuzzy Inference System. International Review of Electrical Engineering-Iree 5, 1165-1171.
Abstract: Fault diagnosis is a major area of investigation for power system and intelligent system applications. This paper proposes an efficient and practical algorithm based on using wavelet MRA coefficients for fault detection and classification, as well as accurate fault location. A three-phase transmission line with series compensation is simulated using MATLAB software. The line currents at both ends are processed using an online wavelet transform algorithm to obtain wavelet MRA for fault recognition. Directions and magnitudes of spikes in the wavelet coefficients are used for fault detection and classification. After identifying the fault section, the summation of the sixth level MRA coefficients of the currents are fed to adaptive neuro-fuzzy inference system (ANFIS) to obtain accurate fault location. The proposed scheme is able to detect all types of internal faults at different locations either before or after the series capacitor, at different inception angles, and at different fault resistances. It can also detect the faulty phase(s) and can differentiate between internal and external faults. The simulation results show that the proposed method has the characteristic of a simple and clear recognition process. We conclude that the algorithm is ready for series compensated transmission lines. Copyright (C) 2010 Praise Worthy Prize S.r.l - All rights reserved
    16.   Malathi, V., Marimuthu, N.S., Baskar, S., 2010. Intelligent approaches using support vector machine and extreme learning machine for transmission line protection. Neurocomputing 73, 2160-2167.
Abstract: This paper proposes two approaches based on wavelet transform-support vector machine (WT-SVM) and wavelet transform-extreme learning machine (WT-ELM) for transmission line protection. These methods uses fault current samples for half cycle from the inception of fault. The features of the line currents are extracted by first level decomposition of the current samples using discrete wavelet transform (DWT) and extracted features are applied as inputs to SVM and ELM for faulted phase detection, fault classification, location and discrimination between fault and switching transient condition. The feasibility of the proposed methods have been tested on a 240-kV, 225-km transmission line for all the 10 types of fault using MATLAB Simulink. Upon testing on 9600 fault cases with varying fault resistance, fault inception angle, fault distance, pre-fault power level, and source impedances, the performance of the proposed methods are quite promising. The performance of the proposed methods is compared in terms of classification accuracy and fault location error. The results indicate that SVM based approach is accurate compared to ELM based approach for fault classification. For fault location, the maximum error is less with SVM than ELM and the mean error of SVM is slightly higher than ELM. (C) 2010 Elsevier B.V. All rights reserved
    17.   Wei, L., Guo, W., Wen, F., Ledwich, G., Liao, Z., Xin, J., 2010. Waveform matching approach for fault diagnosis of a high-voltage transmission line employing harmony search algorithm. Iet Generation Transmission & Distribution 4, 801-809.
Abstract: An accurate and effective technology for fault diagnosis of a high-voltage transmission line plays an important role in supporting rapid system restoration. The fault diagnosis of a high-voltage transmission line involves three major tasks, namely fault-type identification, fault location and fault time estimation. The diagnosis problem is formulated as an optimisation problem in this work: the variables involved in the fault diagnosis problem, such as the fault location, and the unknown variables such as ground resistance, are taken into account as optimisation variables; the sum of the discrepancy of the approximation components of the actual and expected waveforms is taken as the optimisation objective. Then, according to the characteristics of the formulated optimisation problem, the harmony search, an effective heuristic optimisation algorithm developed in recent years, is employed to solve this problem. Test results for a sample power system have shown that the developed fault diagnosis model and method are correct and efficient
    18.   Korres, G.N., Apostolopoulos, C.A., 2010. Precise fault location algorithm for double-circuit transmission lines using unsynchronised measurements from two anti-parallel ends. Iet Generation Transmission & Distribution 4, 824-835.
Abstract: A new fault location algorithm for double-circuit transmission lines with availability of complete measurements from two anti-parallel end of the line is presented. Sequence voltage and current phasors from these ends are taken as inputs and no synchronisation between them is needed. Using the pre-fault data, the synchronisation angles between measurements at the reference and the anti-parallel ends are obtained. Using the fault data, the faulted circuit is determined and the sequence voltages and currents at the fault point are calculated as a function of the fault distance. Finally, using the fault boundary conditions that exist for a given fault type, the fault location is derived and solved by an iterative method. Owing to zero-sequence mutual coupling, it is not straightforward to express the zero-sequence voltage and current at the fault point as a function of the zero-sequence voltages and currents at the two measuring ends and the distance to fault. To overcome this problem, a modal transformation matrix is introduced to obtain the modal networks, which are decoupled and can be analysed independently. Based on distributed parameter line model, the proposed algorithm fully considers the effects of shunt capacitances and thus achieves superior locating accuracy, especially for long lines. Mutual coupling between circuits, source impedances and fault resistance do not influence the locating accuracy of the algorithm. The simulation results using ATP-EMTP and MATLAB demonstrate the effectiveness and accuracy of the proposed algorithm
    19.   Yu, C.S., 2010. An Unsynchronized Measurements Correction Method for Two-Terminal Fault-Location Problems. Ieee Transactions on Power Delivery 25, 1325-1333.
Abstract: This paper presents a method to correct the unsynchronized measurements for two-terminal fault-location problems. First, a synchronization index is defined to check whether the measurements are synchronized. A modified secant method-based algorithm is then developed to obtain a synchronization angle and correct the unsynchronized measurements. When the unsynchronized measurements are corrected, the fault location can be simultaneously obtained from the intermediate result of the proposed computation. Thus, although the proposed method is developed to correct the unsynchronized measurements, the fault-location problem can also be solved. Compared with the previous works, the proposed iteration equation is simpler. The MATLAB/SIMULINK simulator is used to evaluate the effectiveness of the proposed method
    20.   Manassero, G., Senger, E.C., Nakagomi, R.M., Pellini, E.L., Rodrigues, E.C.N., 2010. Fault-Location System for Multiterminal Transmission Lines. Ieee Transactions on Power Delivery 25, 1418-1426.
Abstract: This research presents the development and implementation in a computational routine of algorithms for fault location in multiterminal transmission lines. These algorithms are part of a fault-location system, which is capable of correctly identifying the fault point based on voltage and current phasor quantities, calculated by using measurements of voltage and current signals from intelligent electronic devices, located on the transmission-line terminals. The algorithms have access to the electrical parameters of the transmission lines and to information about the transformers loading and their connection type. This paper also presents the development of phase component models for the power system elements used by the fault-location algorithms
    21.   Nahman, J.M., Salamon, D.D., 2010. Ieee Safety Analysis at Overhead Line Towers in Close Proximity to the Substation. Transactions on Power Delivery 25, 1508-1515.
Abstract: This paper proposes a mathematical model for the analysis of safety conditions at a transmission-line tower located in close proximity to the substation, of which the line is connected to, arising in the case of a single-phase-to-ground fault at the tower. The model takes into account the mutual interaction of the substation and tower ground electrodes affecting the currents discharging from these electrodes into the surrounding soil and the potential distribution on the ground surface. A practical, quite general case of a double-circuit line having two ground wires of different types is considered. It was shown that the negligence of the mutual effects of the two ground electrodes might lead to very erroneous conclusions regarding the maximum touch-and-step voltages appearing at the tower location in the fault case, implying unnecessary extra cost and labor to meet the safety standards
    22.   He, Z.Y., Zhang, J., Li, W.H., Lin, X.N., 2010. Improved Fault-Location System for Railway Distribution System Using Superimposed Signal. Ieee Transactions on Power Delivery 25, 1899-1911.
Abstract: The railway distribution system is a neutral noneffectively grounded medium-voltage network. An advanced fault-location system for this distribution network, called the railway distribution network fault location system, is proposed in this paper. This fault-location system is based on tracing the superimposed signal and the work principle, simulation results, and field tests of the location system are presented. It is able to identify the fault location in a fast and accurate way. Compared with other conventional superimposed signal-based schemes, the system's performance is improved by employing the inject and fault-current detect sensor (IFCDS) to trace the fault signal and wireless to transmit detect information. The IFCDS, which permanently hangs on feeders, is based on the wireless sensor networks technology, so it can network automatically in a certain range, and improve the flexibility of the communication subsystem. Through analyzing the uploaded information by the fault-location computer in the substation, the fault point can be located. Issues of superimposed signals, such as optimal frequency choice, impact of tapped load, fault distance, and fault resistance, and so on are of concern. Through simulation in PSCAD/EMTDC, these issues are fully discussed. At last, the tests in the field show that the system has simple principle, high reliability, fast location speed (usually less than 15 min), and high accuracy (location error is less than 0.5 km)
    23.   Tian, Y., Fan, C.J., Gong, Z.D., 2010. A study on accurate fault location algorithm for parallel transmission line with a teed connection. International Journal of Electrical Power & Energy Systems 32, 697-703.
Abstract: Teed connecting parallel transmission lines frequently subject a variety of technical problems in the view of protection engineering. These problems are mainly due to the mutual coupling between lines and the multiple branch of teed connection, which requires choosing faulted branch before fault location. A new accurate fault location algorithm for parallel transmission line with a teed connection is introduced in this paper. Depending on six-sequence fault component method, the coupled transmission equations are transformed into decoupled ones. Based on the detailed analysis of peculiar characteristic of teed connection, the differential positive sequence component measurement, which is one of the six-sequence fault components, is used to implement fault location for parallel line with a teed connection. The new location algorithm makes full use of the decoupled mode and the teed structure. It is independent of source impedance, fault type, fault resistance and mutual coupling between parallel lines. The algorithm has been tested by EMTP simulations, which indicates that this location method obtains high accuracy under various fault conditions. (C) 2010 Elsevier Ltd. All rights reserved
    24.   Upendar, J., Gupta, C.P., Singh, G.K., 2010. Fault Classification Scheme Based on the Adaptive Resonance Theory Neural Network for Protection of Transmission Lines. Electric Power Components and Systems 38, 424-444.
Abstract: This article presents a new approach to classify various types of power system faults using wavelet transforms and the adaptive resonance theory. The key idea underlying the approach is to decompose a given disturbance signal into other signals, which represents a smoothed and detailed version of the original signal. The proposed technique consists of a preprocessing unit based on discrete wavelet transform in combination with adaptive resonance theory. Through wavelet analysis, faults are decomposed into a series of wavelet components, each of which is a time-domain signal that covers a specific octave frequency band. The parameters selected for fault classification are the detailed coefficients of all phase current signals that are collected only at the sending end of a transmission line. The information is then fed into adaptive resonance theory for classifying the faults. The study is performed on a sample power system network. Extensive simulation studies carried out using MATLAB (http://www.mathworks.com) shows that the proposed algorithm not only provides an accepted degree of accuracy in fault classification under different fault conditions, but it is also reliable, fast, and computationally efficient tool
    25.   Nguyen, T., Liao, Y., 2010. Transmission Line Fault Type Classification Based on Novel Features and Neuro-fuzzy System. Electric Power Components and Systems 38, 695-709.
Abstract: This article presents an adaptive neuro-fuzzy inference system and a set of novel features for the classification of transmission line fault types. The ten common types of faults, including line-to-ground faults, line-to-line faults, line-to-line-to-ground faults, and three-phase faults, are considered in this research. The proposed method employs only current waveforms, and the new features include correlation coefficients and inter-quartile ranges of current signals. For the decision-making system based on the neuro-fuzzy technique, two schemes have been investigatedone consisting of 128 rules and the other with 10 rules. Evaluation studies based on both electromagnetic transient program simulated data and field data have demonstrated very promising results for the proposed method
    26.   Eisa, A.A.A., Ramar, K., 2010. Accurate one-end fault location for overhead transmission lines in interconnected power systems. International Journal of Electrical Power & Energy Systems 32,  383-389.
Abstract: This paper presents a new one-end fault location method for overhead transmission lines embedded in a general n-bus interconnected power system. High accuracy in fault location is achieved by using both an accurate distributed parameters model for the faulted transmission line, and a two-bus Thevenin equivalent network model for the power system that accurately accounts for its interconnectivity. The method has been tested using transient fault data obtained from PSCAD/EMTDC simulations of an 11-bus interconnected power system. The results obtained indicate that the method is capable of estimating the fault distance with high accuracy for various fault conditions. They also indicate that method is sensitive to errors in the value of the local bus impedance, but is insensitive to errors in the value of the remote bus impedance. (C) 2009 Elsevier Ltd. All rights reserved
    27.   Ibrahim, D.K., Eldin, E.T., Abou El-Zahab, E.E., Saleh, S.M., 2010. Unsynchronized Fault-Location Scheme for Nonlinear HIF in Transmission Lines. Ieee Transactions on Power Delivery 25, 631-637.
Abstract: The general aim of this paper is to develop an accurate fault-location scheme that can solve the problems affecting the accuracy of the existing conventional fault locators achieving easier maintenance and restoration time reduction as well as economical aims. This consequently helps to fit the new deregulation policies and competitive marketing. This investigation successfully applies zero-sequence current (3I(o)) from the two terminals for earth high impedance fault (HIF) location, or negative-sequence currents from the two terminals of one faulted phase for line-to-line fault location. The HIF location is determined within only a maximum time of one cycle. The proposed scheme is insensitive to variations of different parameters, such as fault type, HIF behavior, wide-range transmission-line parameters variation, and fault inception angle. Staged fault testing results demonstrate that the proposed algorithm has feasible performance
    28.   Chuang, C.L., Wang, Y.C., Lee, C.H., Liu, M.Y., Hsiao, Y.T., Jiang, J.A., 2010. An Adaptive Routing Algorithm Over Packet Switching Networks for Operation Monitoring of Power Transmission Systems. Ieee Transactions on Power Delivery 25, 882-890.
Abstract: This paper reports on the development and subsequent use of a packet switching communication model for monitoring of power transmission line systems. Modern fault detection and fault location techniques for EHV/UHV transmission networks usually work based on the data measured by a phasor measurement unit (PMU). Digital cameras have also been widely utilized to monitor the physical status of power transmission lines on electricity pylons. PMU measures voltage and current phasors with synchronized time stamps, and then transmits the measured data to a monitoring center for analysis. The transmission of these data is required to be very stable. For the sake of operation speed and system security, the development of an enhanced communication infrastructure that guarantees the quality of service (QoS) for the essential measured data is a crucial issue. We have developed an adaptive routing algorithm for packet switching networks to guarantee the QoS of important power system communications and have conducted computer simulations to demonstrate the effectiveness of the proposed algorithm. The proposed algorithm can minimize transmission delay and reduce the number of redundant transmissions caused by loss of packets. Hence, the simulation results show the feasibility of packet switching networks on monitoring power systems
    29.   Suonan, J., Gao, S.P., Song, G.B., Jiao, Z.B., Kang, X.N., 2010. A Novel Fault-Location Method for HVDC Transmission Lines. Ieee Transactions on Power Delivery 25, 1203-1209.
Abstract: This paper presents a method for locating faults on HVDC transmission lines using two terminal data. Different from those based on the traveling wave principle, the new fault-location algorithm can use any section of the postfault data to locate faults. The proposed method is developed based on the distributed parameter line model in which the voltage distribution over the line can be obtained from the voltage and current measurements at both terminals and point where fault occurs can be identified from the calculated voltage distribution. The fault-location algorithm is performed in time domain and thus a short data window is sufficient for it to achieve satisfactory accuracy in practice. The proposed algorithm is simulated using data of the frequency-dependent line model in EMTDC and data of an existing HVDC line as well. The simulations have shown that this method is valid and is capable of locating the faults occurring on HVDC transmission lines quickly and accurately
    30.   Mohamed, E.A., Talaat, H.A., Khamis, E.A., 2010. Fault diagnosis system for tapped power transmission lines. Electric Power Systems Research 80, 599-613.
Abstract: This paper presents a design for a fault diagnosis system (FDS) for tapped HV/EHV power transmission lines. These lines have two different protection zones. The proposed approach reduces the cost and the complexity of the FDS for these types of lines. The FDS consists basically of fifteen artificial neural networks (ANNs). The FDS basic objectives are mainly: (I) the detection of the system fault; (2) the localization of the faulted zone; (3) the classification of the fault type; and finally (4) the identification of the faulted phase. This FDS is structured in a three hierarchical levels. In the first level, a preprocessing unit to the input data is pet-formed. An ANN, in the second level, is designed in order to detect and zone localize the line faults. In the third level, two zone diagnosis systems (ZDS) are designed. Each ZDS is dedicated to one zone and consists of seven parallel-cascaded ANN's. Four-parallel ANN's are designed in Order to achieve the fault type classification. While, the other three cascaded ANN's are designed mainly for the selection of the faulted phase. A smoothing unit is also configured to smooth out the output response of the proposed FDS. The proposed FDS is designed and evaluated using the local measurements of the three-phase voltage and current samples acquired at only one side. The sampling rate was taken 16 samples per cycle of the power frequency. Data window of 4 samples was utilized. These samples were generated using the EMTP simulation program, applied to the High-Dam/Cairo 500 kV tapped transmission line. All possible shunt fault types were considered. The effect of fault location and fault incipience time were also included. Moreover, the effect of load and capacitor switchings on the FDS performance was investigated. Testing results have proved the capability as well as the effectiveness of the proposed FDS. (C) 2009 Elsevier B.V. All rights reserved
    31.   Sadeh, J., Adinehzadeh, A., 2010. Accurate fault location algorithm for transmission line in the presence of series connected FACTS devices. International Journal of Electrical Power & Energy Systems 32 , 323-328.
Abstract: This paper presents a new and accurate fault location algorithm based on distributed time domain line model for a transmission line compensated with series connected FACTS device. In the proposed algorithm, in order to compute the voltage drop across the series device during the fault period, the series device model and knowledge about the operating mode of the compensating device are not utilized. For this reason, the proposed technique can be easily applied to any series FACTS compensated line. Samples of voltage and current at both ends of the line are taken synchronously and used to calculate the location and resistance of the fault. The proposed algorithm is not sensitive to fault resistance and fault inception angle and does not require any knowledge of equivalent source impedances. This method has been tested using EMTP/ATP model of a 400 kV, 300 km transmission line compensated with a series FACTS device. The results of computer simulations for different operating conditions demonstrate the very high accuracy and robustness of the algorithm. (C) 2009 Elsevier Ltd. All rights reserved
    32.   Baghaee, H.R., Mirsalim, M., Kashefi-Kaviani, A., Gharehpetian, G.B., 2009. Optimal Allocation of Multi-Type FACTS Devices to Improve Security and Reduce the Losses and Fault Level Using Multi-Objective Particle Swarm Optimization. International Review of Electrical Engineering-Iree 4, 1326-1335.
Abstract: Flexible alternative current transmission system devices can regulate the active and reactive power as well as voltage-magnitude. Placement of these devices in suitable locations can lead to the control of line power flow, bus voltages and short circuit currents at desired levels and as a result, improvement of power system security margins. This paper presents an optimal allocation algorithm for FACTS devices based on a novel m-objective particle swarm optimization method considering both power system costs and security. The proposed algorithm has successfully been applied to an IEEE 30-bus power system and the results are presented and discussed Copyright (C) 2009 Praise Worthy Prize S.r.l. - All rights reserved
    33.   Kang, N., Liao, Y., 2009. New Fault Location Technique for Series Compensated Transmission Lines. International Review of Electrical Engineering-Iree 4, 1385-1390.
Abstract: A new fault location algorithm for series compensated transmission line utilizing two-terminal unsynchronized voltage and current measurements is presented in this paper. The distributed parameter line model is adopted to fully take into account the shunt capacitance. The fault impedance is assumed to be pure resistive. By formulating the fault current in terms of unknown fault location, boundary conditions under dififerent fault types can be made use of to derive the fault location. Two subroutines assuming the fault occurs on the left or right side of the series compensator are developed and the principle to identify the cot-reel fault location estimate is described Matlab SimPowerSystems is utilized to simulate the faults of various conditions and generate the voltage and current waveforms from both terminals of the series compensated single-circuit line. The fault location results are quite accurate based on simulation studies. Copyright (C) 2009 Praise Worthy Prize S.r.l. - All rights reserved
    34.   da Silva, M., Coury, D.V., Oleskovicz, M., Segatto, E.C., 2010. Combined solution for fault location in three-terminal lines based on wavelet transforms. Iet Generation Transmission & Distribution 4, 94-103.
Abstract: This work presents the study and development of a combined fault location scheme for three-terminal transmission lines using wavelet transforms (WTs). The methodology is based on the low- and high-frequency components of the transient signals originated from fault situations registered in the terminals of a system. By processing these signals and using the WT, it is possible to determine the time of travelling waves of voltages and/or currents from the fault point to the terminals, as well as estimate the fundamental frequency components. A new approach presents a reliable and accurate fault location scheme combining some different solutions. The main idea is to have a decision routine in order to select which method should be used in each situation presented to the algorithm. The combined algorithm was tested for different fault conditions by simulations using the ATP (Alternative Transients Program) software. The results obtained are promising and demonstrate a highly satisfactory degree of accuracy and reliability of the proposed method
    35.   Jamali, S., Parham, A., 2010. New approach to adaptive single pole auto-reclosing of power transmission lines. Iet Generation Transmission & Distribution 4, 115-122.
Abstract: In this study, a novel digital algorithm is introduced for recognition of arcing (transient) faults and determination of dead time for adaptive auto-reclosing. The algorithm distinguishes between arcing and permanent faults by using the zero sequence voltage measured at the relaying point. If the fault is recognised as an arcing fault, then the third harmonic of the zero sequence voltage is used to evaluate the extinction time of secondary arc and to initiate reclosing signal. The proposed algorithm uses an adaptive threshold level and therefore no significant adjustment is needed for different transmission systems. Moreover, its performance is independent to fault location, line parameters and the system pre-fault operating conditions. The algorithm has been successfully tested for various faults and operating conditions on a 400 kV overhead line using the electro-magnetic transient program (EMTP). The test results have demonstrated validity of the algorithm in determining the secondary arc extinction time and blocking unsuccessful automatic reclosing during permanent faults
    36.   Siozinys, V., 2010. Transmission Line Fault Distance Measurement based on Time Difference between Travelling Wave Reflection and Refraction. Elektronika Ir Elektrotechnika 25-28.
Abstract: V. Siozinys. Transmission Line Fault Distance Measurement based on Time Difference between Travelling Wave Reflection and Refraction H Electronics and Electrical Engineering. - Kaunas: Technologija, 2010. - No. 2(98). - P. 25-28. The relay protection principles based on travelling wave are observed. Transmission line fault distance measurement algorithm based on time difference between travelling wave reflection and refraction is proposed. An algorithm, its mathematical prove, modelling results and errors are presented in article. The simple scheme calculation example is presented to describe fault location algorithm behaviour. Transmission line model with 4 lines which length is from 200 to 400 meters is used to represent algorithm. The distance to fault location calculated error is in range of 1-3%. III. 3, bibl. 4 (in English; summaries in English, Russian and Lithuanian)
    37.   Osman, A.H., Noureldin, A., El-Shafie, A., McGaughey, D.R., 2010. Fast orthogonal search approach for distance protection of transmission lines. Electric Power Systems Research 80, 215-221.
Abstract: A distance protection scheme for transmission lines based on analyzing the measured voltage and current signals at the relay location using fast orthogonal search (FOS) is presented in this paper. FOS has the ability to accurately provide fast estimate of the voltage and current fundamental frequency phasors that are required for a digital distance relay. Compared to the conventional FFT, FOS can estimate the fundamental phasors with higher accuracy and less number of samples. The proposed scheme has been tested on a transmission line model to verify the merit of this approach. The tests presented include solid ground faults, phase faults, and high impedance faults at different fault locations and loading conditions. The proposed scheme can classify all fault cases in less than one cycle after the inception of the faults. (C) 2009 Elsevier B.V. All rights reserved
    38.   Naimi, H.M., Sanaye-Pasand, M., 2009. A New Distance Measurement Algorithm for Series Compensated Transmission Lines. International Review of Electrical Engineering-Iree 4, 932-942.
Abstract: Series capacitors (SCs) are installed on long transmission lines to reduce the inductive reactance of lines. This makes it appear electrically shorter and increases the power transfer capability. Series capacitors and their associated over-voltage protection devices (typically metal oxide varistors, and/or air gaps) create several problems for protection relays and fault locators including voltage and/or current inversion, sub-harmonic oscillations, transients caused by the air-gap flashover and sudden changes in the operating reach. In this paper, an accurate fault location algorithm for series compensated power transmission lines is presented The distance to fault is calculated from the fault loop quantities composed as for the classic fault locators, but in case of voltages additionally the compensation for the voltage drop across the bank (or banks) of series capacitors is performed The sample fault cases and the evaluation results for the developed algorithm are presented The fault locator simulated on a PC using PSCAD. The operating behaviour of the fault locator was assessed using a 400 kV, 400km double end fed simulated transmission line with solid and resistive single line to ground and three phase faults at various locations on the line. it relies totally on locally derived information. Copyright (C) 2009 Praise Worthy Prize S.r.l. - All rights reserved
    39.   Mirzai, M.A., Afzalian, A.A., 2010. A Novel Fault-Locator System; Algorithm, Principle and Practical Implementation. Ieee Transactions on Power Delivery 25, 35-46.
Abstract: This paper presents a novel fault-locator system for radial distribution feeders based on the feeder architecture and voltage and current measurements at a subtransmission substation (63/20 kV). The proposed algorithm determines the fault location precisely by considering the variable characteristic of the load, unbalanced condition, and unsymmetrical nature of distribution feeders. Load variations affect the accuracy of fault-locator systems significantly. Real-time load estimation is implemented to reduce the differences between the calculated fault location and the actual fault location. In addition, self-supervisory characteristics are added to the system to increase the accuracy of the collected data. Actual test results demonstrate the effectiveness of the system in practical applications
    40.   Izykowski, J., Rosolowski, E., Balcerek, P., Fulczyk, M., Saha, M.M., 2010. Accurate Noniterative Fault Location Algorithm Utilizing Two-End Unsynchronized Measurements. Ieee Transactions on Power Delivery 25, 72-80.
Abstract: This paper presents a new two-terminal impedance-based fault location algorithm, which takes into account the distributed parameter line model. The algorithm utilizes unsynchronized measurements of voltages and currents from two ends of a line and is formulated in terms of the fundamental frequency phasors of symmetrical components of the measured signals. First, an analytical synchronization of the unsynchronized measurements is performed with use of the determined synchronization operator. Then, the distance to fault is calculated as for the synchronized measurements. Simultaneous usage of two kinds of symmetrical components for determining the synchronization operator makes that the calculations are simple, noniterative and at the same time highly accurate. The developed fault location algorithm has been thoroughly tested using signals of ATP-EMTP versatile simulations of faults on a transmission line. The presented evaluation shows the validity of the developed fault location algorithm and its high accuracy
    41.   Bugajska, A., Wlodarczyk, M., 2009. Ambiguity in determining the location of long line fault by measurement of the input impedance. Przeglad Elektrotechniczny 85, 274-276.
Abstract: The paper presents ambiguities in determining the location of the insulation weakening in the long line (cable line or transmission line) by measurement of the input impedance. These ambiguities can arise from improper selection of frequency at which the input impedance is measured. This paper presents the optimal frequency ranges, at which these ambiguities do not occur. (Ambiguity in determining the location of long line fault by measurement of the input impedance)
    42.   Istrate, M., Miron, A., Istrate, C., Gusa, M., Machidon, D., 2009. Single-phased Fault Location on Transmission Lines Using Unsynchronized Voltages. Advances in Electrical and Computer Engineering 9, 51-56.
Abstract: The increased accuracy into the fault's detection and location makes it easier for maintenance, this being the reason to develop new possibilities for a precise estimation of the fault location. In the field literature, many methods for fault location using voltages and currents measurements at one or both terminals of power grids' lines are presented. The double-end synchronized data algorithms are very precise, but the current transformers can limit the accuracy of these estimations. The paper presents an algorithm to estimate the location of the single-phased faults which uses only voltage measurements at both terminals of the transmission lines by eliminating the error due to current transformers and without introducing the restriction of perfect data synchronization. In such conditions, the algorithm can be used with the actual equipment of the most power grids, the installation of phasor measurement units with GPS system synchronized timer not being compulsory. Only the positive sequence of line parameters and sources are used, thus, eliminating the incertitude in zero sequence parameter estimation. The algorithm is tested using the results of EMTP-ATP simulations, after the validation of the ATP models on the basis of registered results in a real power grid
    43.   Izykowski, J., Rosolowski, E., 2009. Application of synchronised distributed measurements to location of faults on overhead lines. Przeglad Elektrotechniczny 85, 21-25.
Abstract: This paper presents an analysis of application of synchronised distributed measurements to location of faults on power overhead lines. Use of complete two-end measurements has been considered. For this option a possibility of fault location combined with estimation of the line parameters has been presented. Then, an analysis of use of incomplete two-end measurements has been carried out. Attention has been focused on the fault location algorithm which is immune to errors resulting from saturation of current transformers on one side of the line (Application of synchronised distributed measurements to location of faults on overhead lines)
    44.   Kang, S.H., Ahn, Y.J., Kang, Y.C., Nam, S.R., 2009. A Fault Location Algorithm Based on Circuit Analysis for Untransposed Parallel Transmission Lines. Ieee Transactions on Power Delivery 24,  1850-1856.
Abstract: This paper proposes a fault-location algorithm for ultra-high-voltage untransposed parallel transmission lines that only use the voltages and currents at the local end. The proposed algorithm uses the voltage equation for the faulted phase of the faulted line. The equation contains the fault distance, fault resistance, and fault current. To obtain the fault current, Kirchhoff's voltage law is applied on the loops of three phases consisting of the faulted line and the adjacent parallel line. The fault current can be represented in terms of the fault distance. Inserting the fault current into the voltage equation results in an equation that contains only two parameters (i.e., the fault distance and fault resistance). The fault distance is estimated by solving the equation. Test results indicated that the algorithm accurately estimates the fault distance regardless of the fault resistance and mutual coupling effects
    45.   Sadeh, J., Afradi, H., 2009. A new and accurate fault location algorithm for combined transmission lines using Adaptive Network-Based Fuzzy Inference System. Electric Power Systems Research 79, 1538-1545.
Abstract: This paper presents a new and accurate algorithm for locating faults in a combined overhead transmission line with underground power cable using Adaptive Network-Based Fuzzy Inference System (ANFIS). The proposed method uses 10 ANFIS networks and consists of 3 stages, including fault type classification. faulty section detection and exact fault location. In the first part. an ANFIS is used to determine the fault type, applying four inputs, i.e., fundamental component of three phase currents and zero sequence current. Another ANFIS network is used to detect the faulty section, whether the fault is on the overhead line or on the underground cable. Other eight ANFIS networks are utilized to pinpoint the faults (two for each fault type). Four inputs, i.e., the dc component of the current, fundamental frequency of the voltage and current and the angle between them, are used to train the neuro-fuzzy inference systems in order to accurately locate the faults on each part of the combined line. The proposed method is evaluated under different fault conditions such as different fault locations, different fault inception angles and different fault resistances. Simulation results confirm that the proposed method can be used as an efficient means for accurate fault location on the combined transmission lines. (C) 2009 Elsevier B.V. All rights reserved
    46.   Lin, X.N., Weng, H.L., Wang, B., 2009. A generalized method to improve the location accuracy of the single-ended sampled data and lumped parameter model based fault locators. International Journal of Electrical Power & Energy Systems 31, 201-205.
Abstract: The necessity for very high accuracy in fault location is generally becoming more and more important. In this paper, a new generalized algorithm which can improve the accuracy of all fault location algorithms based on the lumped parameter model and single-ended data is presented. The measured distance resulting from the lumped parameter model can be converted to the positive sequence measured impedance matching with the model. Then, the relation between real distance and positive sequence measured impedance of fault circuit based on Bergeron model can be derived according to the analysis of solid grounded faults. Then the improved algorithm resulting from the relation of real distance and measured distance can be obtained. Theoretically, the proposed algorithm is independent of shunt distributed capacitance of transmission lines. Besides, the algorithm is based on power-frequency voltages and currents, and hence high sampling rate is unnecessary. Therefore, it can be implemented in the existing protection devices easily. This paper presents the theory of the technique and the results of ATP simulation tests to demonstrate its performance. (C) 2009 Elsevier Ltd. All rights reserved
    47.   Bhowmik, P.S., Purkait, P., Bhattacharya, K., 2009. A novel wavelet transform aided neural network based transmission line fault analysis method. International Journal of Electrical Power & Energy Systems 31, 213-219.
Abstract: In the present scenario of market driven business, power supply has become more like a commodity. Reliable and quality power need to be ensured to meet customer requirements. In such a situation, it is extremely important that transmission line faults be identified accurately, reliably and in quick time. Advanced signal processing tools such as discrete wavelet transform (DWT) can be used very effectively for parameterisation and characterization of the fault signals. On the other hand, properly configured neural network (NN) can be utilized for classification of the faults based on the DWT signal, The present contribution uses electromagnetic transient program (EMTP) for modeling of a real transmission system and MATLAB for DWT and NN. Various types of faults have been simulated at different locations along the transmission line and an attempt has been made to correctly identify and locate the fault. (C) 2009 Elsevier Ltd. All rights reserved
    48.   Rosolowski, E., Izykowski, J., Saha, M.M., Balcerek, P., Fulczyk, M., 2009. Accurate transmission line fault location using two-terminal measurement data without time synchronisation. Przeglad Elektrotechniczny 85, 170-174.
Abstract: This paper presents a new impedance-based fault location algorithm. Unsynchronised measurements of voltages and currents from two ends of a line are utilised as the input data. The algorithm is formulated with use of the distributed parameter line model. Simultaneous usage of two kinds of symmetrical components for determining the synchronisation operator makes that the calculations are non-iterative. The presented example illustrates the validity of the delivered fault location algorithm and its high accuracy
    49.   Liao, Y., 2009. Fault location observability analysis and optimal meter placement based on voltage measurements. Electric Power Systems Research 79, 1062-1068.
Abstract: Various transmission line fault location algorithms have been proposed in the past depending on measurernents available. These methods evince that if a sufficient number of meters are placed in a power network to record the fault measurements, then the fault location can be reliably estimated. A relevant question to ask may be: how many meters are sufficient in order to derive a reliable and unique fault location estimate for a given network? This paper addresses this question by defining and performing the fault location observability analysis. An optimal meter placement scheme is proposed for determining the optimal locations to place meters so as to make the system observable while minimizing the required number of meters to reduce costs. The proposed method is especially useful for power networks where digital relays have not yet been widely adopted and measuring devices Such as digital fault recorders are deployed for monitoring purposes. A sample power network has been employed to illustrate the proposed method. (C) 2009 Elsevier B.V. All rights reserved
    50.   Firouzjah, K.G., Sheikholeslami, A., 2009. A current independent method based on synchronized voltage measurement for fault location on transmission lines. Simulation Modelling Practice and Theory 17, 692-707.
Abstract: This paper presents a new method based on synchronized voltage measurement technique in order to identify the fault locations in two and three-terminal transmission lines. Due to common problems of current transformers in distance protection of power system and as result increasing cost and reduction of protection accuracy, proposed method is independent of current measurement and based on transmission line terminals voltages measurement. Pre-fault and post-fault voltages at both ends of the line are measured synchronously and used to calculate the fault location. Proposed method calculates the fault location using Thevenin model of faulted system and transforms the whole parameters to symmetric components. Using proposed technique, fault location can be calculated with a lower than 0.6% error without using current transformers. EMTP/ATP simulation results and mathematical analysis show that proposed fault location technique is independent of fault type, fault resistance, fault inception angle and loading angle of the transmission line. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved
    51.   Tsuji, K., 2009. Protection Relaying Scheme Based on Fault Reactance Operation Type. Electrical Engineering in Japan 168, 29-40.
Abstract: The theories of operation of existing relays are roughly divided into two types: the current differential type based on Kirchhoff's first law and the impedance type based on Kirchhoff's second law. We can use Kirchhoff's laws to rigorously formulate fault phenomena, so the circuit equations are represented as nonlinear simultaneous equations whose variables are the fault point k and the fault resistance R-f. This method has two defects: (1) a heavy computational burden in iterative calculation by the N-R method and (2) the relay operator cannot easily understand the principle of numerical matrix operation. The new protection relay principles proposed in this paper focus on the fact that the reactance component at the fault point is close to zero. The reactances X-f(S) and Xf((R)) at the ends of the branch are calculated by solution of linear equations. If the signs of X-f(S) and X-f(R) are not the same, it can be inferred that the fault point is located in the branch. This reactance Xf corresponds to the difference in branch reactance between the actual fault point and an imaginary fault point. Thus, the relay engineer can understand the fault location in terms of the concept of "distance." Simulation results using this new method indicate that it can provide much more precise estimation of fault locations than those obtained by inspection of operating transmission lines. (C) 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(1): 29-40, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20720
    52.   Salim, R.H., Resener, M., Filomena, A.D., de Oliveira, K.R.C., Bretas, A.S., 2009. Extended Fault-Location Formulation for Power Distribution Systems. Ieee Transactions on Power Delivery 24,  508-516.
Abstract: In this paper, an extended impedance-based fault-location formulation for generalized distribution systems is presented. The majority of distribution feeders are characterized by having several laterals, nonsymmetrical lines, highly unbalanced operation, and time-varying loads. These characteristics compromise traditional fault-location methods performance. The proposed method uses only local voltages and currents as input data. The current load profile is obtained through these measurements. The formulation considers load variation effects and different fault types. Results are obtained from numerical simulations by using a real distribution system from the Electrical Energy Distribution State Company of Rio Grande do Sul (CEEE-D), Southern Brazil. Comparative results show the technique robustness with respect to fault type and traditional fault-location problems, such as fault distance, resistance, inception angle, and load variation. The formulation was implemented as embedded software and is currently used at CEEE-D's distribution operation center
    53.   Liao, Y., Kang, N., 2009. Fault-Location Algorithms Without Utilizing Line Parameters Based on the Distributed Parameter Line Model. Ieee Transactions on Power Delivery 24, 579-584.
Abstract: This paper presents novel power system transmission-line fault-location algorithms without requiring transmission-line parameters. The voltages and currents from both ends of a line are taken as inputs and no synchronization is required. Both prefault and fault data may be utilized. The proposed methods are based on a distributed parameter line model and, hence, fully consider the impacts of shunt capacitance of the line. Positive-sequence line parameters may also be estimated as a by product. No assumption on the source impedance and fault resistance is made. Evaluation studies based on Electromagnetic Transients Program (EMTP) simulation data demonstrate that the new methods are able to achieve quite accurate estimates
    54.   Song, G.B., Jiale, S., Ge, Y.Z., 2009. An accurate fault location algorithm for parallel transmission lines using one-terminal data. International Journal of Electrical Power & Energy Systems 31, 124-129.
Abstract: An accurate fault location algorithm for parallel transmission lines, using fundamental frequency components of post-fault voltage and current measured at one terminal, is described in this paper. Parallel transmission lines can be decoupled into the common component net and differential component net. In differential component net, the current distributing coefficient is a function of fault distance, and the differential component current at the fault point can be expressed in terms of the current at the local terminal. Therefore, for asymmetrical faults, the phase fault current can also be expressed as a function of local terminal current and fault distance. With the fault boundary conditions for a given fault type. the fault location equations can then be derived. Based on distributed parameter line model, the proposed algorithm achieves superior locating accuracy, with mutual coupling between circuits, source impedance and fault resistance having very little influence on the locating accuracy. The performance of new algorithm is verified by computer simulation results for transposed and non-transposed lines. (c) 2008 Elsevier Ltd. All rights reserved
    55.   Matsuki, J., Hayashi, Y., Nakano, T., Funasaki, Y., 2009. A Fault Location Method Using Air-Gap Fluxes of Synchronous Generator. Electrical Engineering in Japan 167, 20-27.
Abstract: This paper deals with an experimental investigation of a novel fault location method using air-gap flux distributions of a synchronous generator connected to a power system. Air-gap fluxes are the sum of field fluxes and armature reaction fluxes. Changes in armature current and In field current at a fault contribute directly to the armature reaction fluxes and field fluxes, then resultant air-gap fluxes. Therefore, air-gap fluxes can be utilized to locate a fault. Wavelet analysis is applied to the induced voltages of search coils, which are wound around a stator tooth top for measurement of the air-gap flux. It is shown that the fault type and location can be estimated based oil the change in the search coil voltages measured during the fault. (C) 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(3): 20-27, 2009; Published online in Wiley InterScicrice (www. interscience.wiley.com). DOI 10.1002/eej.20707
    56.   Samantaray, S.R., Tripathy, L.N., Dash, P.K., 2009. Differential equation-based fault locator for unified power flow controller-based transmission line using synchronised phasor measurements. Iet Generation Transmission & Distribution 3, 86-98.
Abstract: The fault location algorithm based on a differential equation-based approach for a transmission line employing a unified power flow controller (UPFC) using synchronised phasor measurements is presented. First, a detailed model of the UPFC and its control is proposed and then, it is integrated into the transmission system for accurately simulating fault transients. The method includes the identification of fault section for a transmission line with a UPFC using a wavelet-fuzzy discriminator. Features are extracted using a wavelet transform and the normalised features are fed to the fuzzy logic systems for the identification of fault section. After the identification of the fault section, the control shifts to the differential equation-based fault locator that estimates the fault location in terms of the line inductance up to the fault point from the relaying end. Shunt faults are simulated with wide variations in operating conditions and a pre-fault parameter setting. The instantaneous fault current and voltage samples at the sending and receiving ends are fed to the designed algorithm sample by sample, which results in the fault location in terms of the line inductance. The proposed method is tested for different fault situations with wide variations in operating conditions in the presence of a UPFC
    57.   Peretto, L., Sasdelli, R., Scala, E., Tinarelli, R., 2009. Performance Characterization of a Measurement System for Locating Transient Voltage Sources in Power Distribution Networks. Ieee Transactions on Instrumentation and Measurement 58, 450-456.
Abstract: The problem of locating sources of events such as faults and direct lightning in electric distribution networks can be tackled using several techniques. In this paper, the performance of a distributed measurement system designed and set up by the authors to fit this purpose is evaluated by means of simulations under different realistic operating conditions of the network. The results show the validity and robustness of the proposed approach
    58.   Mahanty, R.N., Gupta, P.B.D., 2008. ANN based fault classifier with wavelet MRA generated inputs. Engineering Intelligent Systems for Electrical Engineering and Communications 16, 109-119.
Abstract: A fault classification approach, which combines the strengths of wavelet analysis and artificial neural network (ANN), is presented in this paper. Wavelet multi-resolution analysis (MRA) level 1 details of three phase currents and the corresponding delta currents are used to generate inputs for an ANN based fault classifier. The proposed approach has been validated by carrying out simulation studies on two typical power system models using EMTP and MATLAB for different types of fault considering wide variations in fault location, fault inception angle, fault point resistance and load impedance
    59.   Reddy, M.J., Mohanta, D.K., 2008. Reply to Discussion on A Wavelet-neuro-fuzzy Combined Approach for Digital Relaying of Transmission Line Faults by Tarkan Erdik and Zekai Sen. Electric Power Components and Systems 36, 1390-1394.
Abstract: The authors are thankful to Tarkan Erdik and Zekai Sen for their keen interest in our article (M. Jaya Bharata Reddy and D. K. Mohanta, A wavelet-neuro-fuzzy combined approach for digital relaying of transmission line faults, Elect. Power Compon. Syst., Vol. 35, No. 12, pp. 1385-1407, 2007) and providing some comments for further elaboration. The discussion raises some points, and this reply is intended to provide some clarifications for other researchers as well
    60.   Roy, D.S., Mohanta, D.K., Panda, A.K., 2008. Software reliability allocation of digital relay for transmission line protection using a combined system hierarchy and fault tree approach. Iet Software 2, 437-445.
Abstract: Digital relay is a special purpose signal processing unit in which the samples of physical parameters such as current, voltage and other quantities are taken. With the proliferation of computer technology in terms of computational ability as well as reliability, computers are being used for such digital signal processing purposes. As far as computer hardware is concerned, it has been growing steadily in terms of power and reliability. Since power plant technology is now globally switching over to such computer-based relaying, software reliability naturally emerges as an area of prime importance. Recently, some computer-based digital relay algorithms have been proposed based on frequency-domain analysis using wavelet-neuro-fuzzy techniques for transmission line faults. A software reliability allocation scheme is devised for the performance evaluation of a multi-functional, multi-user digital relay that does detection, classification and location of transmission line faults
    61.   Liao, Y., 2008. Transmission Line Fault Location Algorithms Without Requiring Line Parameters. Electric Power Components and Systems 36, 1218-1225.
Abstract: When transmission line parameters are not known, a two-terminal algorithm has been proposed in the past for pinpointing the fault location by utilizing voltage and current measurements during the fault. This article puts forth an enhanced method by reducing the number of unknown variables in the Newton-Raphson solution process. The new method is, thus, much simpler and more computationally efficient. In addition, a non-iterative fault location method that is feasible for all types of faults is developed. We have employed the electromagnetic transients program simulation studies to evaluate the performance of the approaches and have obtained quite encouraging results
    62.   Ekici, S., Yildirim, S., Poyraz, M., 2009. A transmission line fault locator based on Elman recurrent networks. Applied Soft Computing 9, 341-347.
Abstract: In this paper, a transmission line fault location model which is based on an Elman recurrent network (ERN) has been presented for balanced and unbalanced short circuit faults. All fault situations with different inception times are implemented on a 380-kV prototype power system. Wavelet transform (WT) is used for selecting distinctive features about the faulty signals. The system has the advantages of utilizing single-end measurements, using both voltage and current signals. ERN is able to determine the fault location occurred on transmission line rapidly and correctly as an important alternative to standard feedforward back propagation networks (FFNs) and radial basis functions (RBFs) neural networks. (C) 2008 Elsevier B.V. All rights reserved
    63.   Dalcastagne, A.L., Noceti, S., Zurn, H.H., Seara, R., 2008. An iterative two-terminal fault-location method based on unsynchronized phasors. Ieee Transactions on Power Delivery 23, 2318-2329.
Abstract: This paper presents a two-terminal fault-location method which works with unsynchronized phasors. The algorithm is iterative and takes a distributed line model into account. At each iteration, the voltage magnitudes computed from the voltage and current phasors measured at the sending and receiving ends are approximated by two straight lines, and the fault-location estimate is obtained by the intersection point of these two lines. The process ends when the difference between two successive fault-location estimates reaches a threshold stipulated by the user. Since the search process is based on voltage magnitudes, the proposed approach does not require synchronism between the measurements obtained at each transmission-line terminal. The evaluation tests show that the fault-location error of the proposed approach is negligible if the phasors measured at both line ends and the line parameters are accurate. For actual fault conditions, the fault-location error is dependent on the accuracy of the phasor magnitudes and transmission-line parameters
    64.   Gou, B., Owusu, K.O., 2008. Linear relation between fault location and the damping coefficient in faulted signals. Ieee Transactions on Power Delivery 23, 2626-2627.
Abstract: With the application of Prony analysis on the fault Signals, this letter obtains a linear relationship between the fault location and the inverse of damping coefficient of the fundamental frequency component in the Prony model. This linear relation naturally implies a simple algorithm to detect the fault location when a fault occurs on a transmission line. The fault signals are simulated in virtual test bed (VTB). Single-phase and three-phase faults with symmetrical and asymmetrical types at different locations on transmission lines are simulated. The fault-phase voltage and current data are recorded and analyzed by applying the Prony analysis
    65.   Bhalja, B., Maheshwari, R.P., 2008. Wavelet-based fault classification scheme for a transmission line using a support vector machine. Electric Power Components and Systems 36, 1017-1030.
Abstract: This article presents a new approach for fault classification in a two-terminal overhead transmission line using a support vector machine classifier. Wavelet transform is used for the decomposition of measured signals and for extraction of the most significant features (feature extraction), which facilitates training of the SVM, particularly in terms of getting better classification performance (high accuracy). After extracting useful features from the measured signals, a decision of fault or no-fault on any phase or multiple phases of a transmission line is carried out using three SVM classifiers. The ground detection task is carried out by a proposed ground index. Two kernel functionspolynomial and Gaussian radial basis function (RBF)have been used, and performances of classifiers have been evaluated based on fault classification accuracy. In order to determine the optimal parametric settings of an SVM classifier (such as the type of kernel function, its associated parameter, and the regularization parameter C), five-fold cross-validation has been applied to the training set. It is observed that an SVM with an RBF kernel provides better fault classification accuracy than that of an SVM with polynomial kernel. One of the key points of this article is the development of an automatic fault data generation model using PSCAD and its application for training and testing of SVMs. To illustrate the effectiveness of the proposed scheme, extensive simulations have been carried out for different fault conditions with wide variations in the operating conditions and source impedances. It has been found that the proposed scheme is very fast and accurate, and it proved to be a robust classifier for digital distance protection
    66.   Rosolowski, E., Izykowski, J., Saha, M.M., 2008. Using of current differential protection signals for fault location on two-terminal line. Przeglad Elektrotechniczny 84, 9-13.
Abstract: This paper presents an accurate fault location algorithm utilising synchronised measurements of two-end currents and one-end voltage in a transmission line. It has been assumed that the algorithm is incorporated into the current differential relay. Therefore, no additional cost for communication between the line ends is demanded. High accuracy of fault location is assured by strict considering of the distributed parameter line model. The performed ATP-EMTP evaluation prove the validity of the presented fault location algorithm and its high accuracy
    67.   Reddy, M.J., Mohanta, D.K., 2008. A DSP based frequency domain approach for classification of transmission line faults. Digital Signal Processing 18, 751-761.
Abstract: This paper employs a digital signal processing (DSP) based frequency domain approach using wavelet multi-resolution analysis (MRA) to overcome difficulties such as fault inception angle, fault impedance and fault distance associated with conventional time domain approach employing voltage and current based measurements for fault classification in case of digital relaying of transmission line. The frequency domain approach for fault classification algorithm uses wavelet MRA technique to extract the features of the current signals based on harmonics generated at the instant of occurrence of fault due to abrupt change of currents in a three phase transmission line. Since choice of particular wavelet plays a vital role for extracting features of generated harmonics, therefore an attempt has been made in this proposed research to extensively investigate using 16 wavelets to establish the superiority of Db4 wavelet over other standard wavelets for accurate fault classification. (c) 2007 Elsevier Inc. All rights reserved
    68.   Liu, C.W., Lien, K.P., Chen, C.S., Jiang, J.A., 2008. A universal fault location technique for N-terminal (N >= 3) transmission lines. Ieee Transactions on Power Delivery 23, 1366-1373.
Abstract: This paper presents a universal fault location technique for N-terminal (N >= 3) transmission lines based on synchronized phasor measurement units. The development of the technique is based on two-terminal fault location technique. The proposed algorithm is different from traditional multiterminal fault location techniques. We apply two-terminal fault location technique to N-terminal transmission lines and propose a novel fault section selector/fault locator. The proposed method has a very good tolerance. The proposed approach provides an analytical solution and its computational burden is very low since it does not require iterative operations. An extensive series of simulations were conducted to verify the accuracy of the proposed algorithm. The average fault location error under various fault conditions is well below 1%
    69.   Perera, N., Rajapakse, A.D., 2008. Fast isolation of faults in transmission systems using current transients. Electric Power Systems Research 78, 1568-1578.
Abstract: This paper presents a protection scheme that is capable of very fast isolation of faults in high voltage transmission systems. Proposed scheme comprises set of relays connected through a telecommunication network, located at different nodes of the system. Relays use wavelet coefficients of current signals to identify the fault directions relative to their location. Fault directions identified at different locations in the system can be combined to determine the faulted line (or busbar) and isolate it. A robust single ended traveling wave based fault distance estimation approach is proposed as a backup in case of communication failure. Investigations were carried out using time domain simulations in PSCAD/EMTDC for a high voltage transmission system. (C) 2008 Elsevier B.V. All fights reserved
    70.   Rosolowski, E., Izykowski, J., Balcerek, P., Fulczyk, M., Saha, M.M., 2007. Fault location on three-terminal lines associated with current differential relays. Przeglad Elektrotechniczny 83,  120-124.
Abstract: This paper presents an algorithm for locating faults on three-terminal power lines for inspection-repair purposes. The presented method has been tested and evaluated with use of fault quantities obtained from versatile simulations'of faults with the software ATP/EMTP package. Results of fault location for the sample faults are delivered and discussed. Fault location accuracy is evaluated and an effective procedure for indicating the faulted line section, i.e. selecting the valid subroutine which yields the result corresponding to the actual fault, is described
    71.   Dong, X.Z., Shi, S.X., Cui, T., Lu, Q., 2008. Optimizing solution of fault location using single terminal quantities. Science in China Series E-Technological Sciences 51, 761-772.
Abstract: This paper firstly evaluated the impedance method and traveling waves method for fault location, and studied the robustness of fault location method based on impedance. Then it proposed an assembled fault location method for a transmission line based on single-terminal electrical quantities, in which the fault zone was firstly determined by impedance method with robustness then the accurate fault position was pinpointed by traveling waves method. EMTP (Electromagnetic Transient Program) simulations showed that the proposed method can overcome the drawbacks of impedance method and traveling waves method when either one is used alone, and improve both the accuracy and the reliability of fault location
    72.   Radojevic, Z., Terzija, V., 2008. Intelligent two-port numerical algorithm for transmission lines disturbance records analysis. Electrical Engineering 90, 323-330.
Abstract: This paper presents a new intelligent numerical algorithm for analysis of transmission lines disturbance records. The algorithm improves the existing methodologies for fault location, adaptive autoreclosure, detailed disturbance records analysis, and fault data management. It is based on the processing of voltages and currents recorded at both of the line terminals. The algorithm does not require synchronized sampling of data from the line terminals. The proposed algorithm is derived in the spectral domain and is based on the application of the discrete Fourier transform. In the algorithm development, the fault arc is included in the complete fault model. One of advanced algorithm features is ability to determine both the arc and the fault/tower-footing resistance. The algorithm is thoroughly tested using EMTP simulation and real data records
    73.   Mora-Florez, J., Melendez, J., Carrillo-Caicedo, G., 2008. Comparison of impedance based fault location methods for power distribution systems. Electric Power Systems Research 78, 657-666.
Abstract: Performance of 10 fault location methods for power distribution systems has been compared. The analyzed methods use only measurements of voltage and current at the substation. Fundamental component during pre-fault and fault are used in these methods to estimate the apparent impedance viewed from the measurement point. Deviation between pre-fault and fault impedance together with the system parameters are used to estimate the distance to the fault point. Fundamental aspects of each method have been considered in the analysis. Power system topology, line and load models and the necessity of additional information are relevant aspects that differentiate one method from another. The 10 selected methods have been implemented, tested and compared in a simulated network. The paper reports the results for several scenarios defined by significant values of the fault location and impedance. The estimated error has been used as a performance index in the comparison. (C) 2007 Elsevier B.V. All rights reserved
    74.   Liao, Y., 2008. Fault location for single-circuit line based on bus-impedance matrix utilizing voltage measurements. Ieee Transactions on Power Delivery 23, 609-617.
Abstract: Diverse transmission line fault location algorithms have been proposed in the past depending on measurements available. Existing algorithms usually require measurements captured from buses of a faulted line. By taking advantage of the bus-impedance matrix technique, this paper presents a possible fault location approach for single-circuit lines utilizing only voltage measurements from one or two buses, which may be distant from the faulted line. With the addition of a fictitious bus where the fault occurs, the transfer impedances of this bus and other buses are revealed as a function of the fault location. Based on the relationship between the bus voltage change due to fault and the transfer impedance, the fault location can be derived. Shunt capacitance of the line is ignored first and then fully considered based on distributed parameter line model. ElectroMagnetic Transients Program simulation studies have shown quite encouraging results
    75.   Reddy, M.J., Mohanta, D.K., 2008. Adaptive-neuro-fuzzy inference system approach for transmission line fault classification and location incorporating effects of power swings. Iet Generation Transmission & Distribution 2, 235-244.
Abstract: In the present milieu, changes in regulations and the opening of power markets have manifested in the form of large amount of power transfer across transmission lines with frequent changes in loading conditions based on market price. Since conventional distance relays may consider power swing as a fault, tripping because of such malfunctioning would lead to serious consequences for power system stability. A frequency domain approach for digital relaying of transmission line faults mitigating the adverse effects of power swing on conventional distance relaying is presented. A wavelet-neuro-fuzzy combined approach for fault location is also presented. It is different from conventional algorithms that are based on deterministic computations on a well-defined model for transmission line protection. The wavelet transform captures the dynamic characteristics of fault signals using wavelet multi-resolution analysis (MRA) coefficients. The fuzzy inference system (FIS) and the adaptive-neuro-fuzzy inference system (ANFIS) are both used to extract important features from wavelet MRA coefficients and thereby to reach conclusions regarding fault location. Computer simulations using MATLAB have been conducted for a 300 km, 400 kV line and results indicate that the proposed localisation algorithm is immune to effects of fault inception, angle and distance. The results contained here validate the superiority of the ANFIS approach over the FIS for fault location
    76.   Wang, C., Jia, Q.Q., Li, X.B., Dou, C.X., 2008. Fault location using synchronized sequence measurements. International Journal of Electrical Power & Energy Systems 30, 134-139.
Abstract: This paper proposes fault location formulas using synchronized sequence measurements. For earth faults, zero-sequence voltages and currents at two terminals of faulted line are applied to fault location. Negative-sequence measurements are utilized for asymmetrical faults and positive-sequence measurements are used for three-phase faults. The fault location formulas are derived from a fault location technique [Wang C, Dou C, Li X, Jia Q. A WAMS/PMU-based fault location technique. Elect Power Syst Res 2007;77(8):936-945.] based on WAMS/PMU. The technique uses synchronized fault voltages measured by PMUs in power network. The formulas are simple and are easy for application. Case studies on a testing network with 500 kV transmission lines including ATP/EMTP simulations are presented. Various fault types and fault resistances are also considered. (c) 2007 Elsevier Ltd. All rights reserved
    77.   Ekici, S., Yildirim, S., Poyraz, M., 2008. Energy and entropy-based feature extraction for locating fault on transmission lines by using neural network and wavelet packet decomposition. Expert Systems with Applications 34, 2937-2944.
Abstract: The aim of this paper is to estimate the fault location on transmission lines quickly and accurately. The faulty current and voltage signals obtained from a simulation are decomposed by wavelet packet transform (WPT). The extracted features are applied to artificial neural network (ANN) for estimating fault location. As data sets increase in size, their analysis become more complicated and time consuming. The energy and entropy criterion are applied to wavelet packet coefficients to decrease the size of feature vectors. The test results of ANN demonstrate that the applying of energy criterion to current signals after WPT is a very powerful and reliable method for reducing data sets in size and hence estimating fault locations on transmission lines quickly and accurately. (c) 2007 Elsevier Ltd. All rights reserved
    78.   Samantaray, S.R., Dash, P.K., 2008. Transmission line distance relaying using machine intelligence technique. Iet Generation Transmission & Distribution 2, 53-61.
Abstract: A new approach for distance relaying of transmission line using machine intelligence technique such as support vector machine (SVM) is presented. The proposed SVM technique is used for faulty phase selection and ground detection in different fault situations that occur on large power transmission line. Post-fault current and voltage samples for one-fourth cycle (five samples) are used as inputs to SVM 1, which provide output for faulty phase selection. SVM 2 is trained and tested with zero-sequence components of fundamental, third and fifth harmonic components of the post-fault current signal to provides the involvement of ground in the fault process. The polynomial and Gaussian kernel SVMs are designed to provide the most optimised boundary for classification. The total time taken for faulty phase selection and ground detection is 10 ms (half cycle) from the inception of fault. Also the proposed technique is tested on experimental set-up with different fault situations. The test results are compared with those of the radial basis function neural network and were found to be superior with respect to efficiency and speed. The classification test results from SVMs are accurate for simulation model and experimental set-up, and thus provide fast and robust protection scheme for distance relaying in transmission line
    79.   Reddy, M.J., Mohanta, D.K., 2007. A wavelet-fuzzy combined approach for classification and location of transmission line faults. International Journal of Electrical Power & Energy Systems 29, 669-678.
Abstract: This paper presents a real-time wavelet-Fuzzy combined approach for digital relaying. The algorithm for fault classification employs wavelet multi resolution analysis (MRA) to overcome the difficulties associated with conventional voltage and current based measurements due to effect of factors such as fault inception angle, fault impedance and fault distance. The proposed algorithm for fault location, different from conventional algorithms that are based on deterministic computations on a well-defined model to be protected, employs wavelet transform together with fuzzy logic. The wavelet transform captures the dynamic characteristics of the non-stationary transient fault signals using wavelet MRA coefficients. The fuzzy logic is employed to incorporate expert evaluation through fuzzy inference system (FIS) so as to extract important features from wavelet MRA coefficients for obtaining coherent conclusions regarding fault location. Computer simulations using MATLAB have been conducted for a 300 Km 400 KV line. Simulation results indicate that both the classification and localization algorithms are immune from effects of faults inception angle, impedance and distance. The most significant contribution of this paper is that the proposed location algorithm has a maximum error of 6.5% with a computational time of about one cycle. Thus both classification and location algorithms can be used as effective tools for real-time digital relaying purpose. (C) 2007 Elsevier Ltd. All rights reserved
    80.   Izykowski, J., Rosolowski, E., Saha, M.M., Fulezyk, M., Balcerek, P., 2007. A fault-location method for application with current differential relays of three-terminal lines. Ieee Transactions on Power Delivery 22, 2099-2107.
Abstract: This paper presents a new method for locating faults on three-terminal power lines. Estimation of a distance to fault and indication of a faulted section is performed using three-phase current from all three terminals and additionally three-phase voltage from the terminal at which a fault locator is installed. Such a set of synchronized measurements has been taken into consideration with the aim of developing a fault-location algorithm for applications with current differential relays of three-terminal lines. The delivered fault-location algorithm consists of three subroutines designated for locating faults within particular line sections and a procedure for indicating the faulted line section. Testing and evaluation of the algorithm has been performed with fault data obtained from versatile Alternate Transients Program-Electromagnetic Transients Program simulations. The sample results of the evaluation are reported and discussed
    81.   Choi, M.S., Lee, S.J., Lim, S.I., Lee, D.S., Yang, X., 2007. A direct three-phase circuit analysis-based fault location for line-to-line fault. Ieee Transactions on Power Delivery 22, 2541-2547.
Abstract: From a direct three-phase circuit analysis, an accurate fault-location algorithm has been obtained for the line-to-line fault as an extension of the author's previous work for line-to-ground fault location. Robustness of the proposed algorithm to load impedance uncertainty is enhanced by the introduction of impedance compensation using voltage and current measurements. Simulation results show a high degree of accuracy and robustness to load uncertainty
    82.   Reddy, M.J., Mohanta, D.K., 2007. A wavelet-neuro-fuzzy combined approach for digital relaying of transmission line faults. Electric Power Components and Systems 35, 1385-1407.
Abstract: The proposed algorithm for fault location, different from conventional algorithms that are based on deterministic computations on a well-defined model to be protected, employs wavelet transform together with fuzzy inference system (FIS) and the adaptive neuro-fuzzy inference system (ANFIS) to incorporate expert evaluation so as to extract important features from wavelet multi-resolution analysis (MRA) coefficients for obtaining coherent conclusions regarding fault location. Simulation results indicate that both the classification and localization algorithms are immune to the effects of fault inception angle, impedance and distance. The most significant contribution of this article is that the proposed ANFIS approach has superiority over FIS for location of transmission line faults and thus can be used as an effective tool for real-time digital relaying purposes
    83.   Samantaray, S.R., Dash, P.K., Panda, G., 2007. Distance relaying for transmission line using support vector machine and radial basis function neural network. International Journal of Electrical Power & Energy Systems 29, 551-556.
Abstract: The proposed technique consists of preprocessing the fault current signal samples using discrete wavelet transform to yield the change in energy (cc) and standard deviation (sd) at the appropriate level of decomposition of fault current and voltage signal for faulty phase identification and fault location determination. After feature extraction (ce and sd) from fault current signal, support vector machine (SVM) is used for decision of fault or no-fault on any phase or multiple phases of the transmission line. The ground detection is done by a proposed indicator 'index' with a threshold value. Once the faulty phases are identified, the fault location from the relaying point can be accurately estimated using RBFNN (radial basis function neural network) with recursive least square algorithm. For fault location both current and voltage signals are preprocessed through wavelet transform to yield change in energy (cc) and standard deviation (sd) which are used to train and test the RBFNN to provide fault location from the relaying point accurately. The combined SVM and RBFNN based technique is tested for faults with wide range of operating conditions and provides accurate results for fault classification and location determination, respectively. (c) 2007 Elsevier Ltd. All rights reserved
    84.   Liao, Y., 2007. Unsynchronized fault location based on distributed parameter line model. Electric Power Components and Systems 35, 1061-1077.
Abstract: This article presents a transmission line fault location algorithm based on distributed parameter line model by utilizing unsynchronized voltage and current measurements from two terminals of the line. The new solution fully considers the impacts of the shunt capacitance of the line and is virtually independent of fault resistance and source impedance. Evaluation studies based on simulation studies for verifying the accuracy of the algorithm are reported, and quite promising results have been achieved
    85.   Liao, Y., Kezunovic, M., 2007. Optimal estimate of transmission line fault location considering measurement errors. Ieee Transactions on Power Delivery 22, 1335-1341.
Abstract: Various transmission line fault location algorithms have been proposed in the past depending on the measurements available. These algorithms perform well when the measurements utilized are accurate; they may yield erroneous results when the measurements contain considerable errors. In some cases, there are redundant measurements available for fault location purposes, and it may be possible to design an optimal estimator for the fault location based on nonlinear estimation theories. This paper aims at proposing a possible method for deriving an optimal estimate of the fault location that is capable of detecting and identifying the bad measurement data, minimizing the impacts of the measurement errors and thus significantly improving the fault location accuracy. The solution is based on the distributed parameter line model and thus fully considers the effects of shut capacitances of the line. Since field data are not available, case studies based on simulated data are presented for demonstrating the effectiveness of the new method
    86.   Jung, C.K., Lee, J.B., Wang, X.H., Song, Y.H., 2007. Wavelet based noise cancellation technique for fault location on underground power cables. Electric Power Systems Research 77, 1349-1362.
Abstract: This paper describes a new algorithm to identify the reflective waves for fault location in noisy environment. The new algorithm is based on the correlation of detail components at adjacent levels of stationary wavelet transform of current signal from one end of the cable. The algorithm is simple and straightforward. Simulation results based on a real power transmission system proved it can detect and locate the fault in very difficult situations. (c) 2006 Elsevier B.V. All rights reserved
    87.   Jung, C.K., Kim, K.H., Lee, J.B., Klockl, B., 2007. Wavelet and neuro-fuzzy based fault location for combined transmission systems. International Journal of Electrical Power & Energy Systems 29, 445-454.
Abstract: This paper describes the fault location algorithm using neuro-fuzzy systems in combined transmission lines with underground power cables. The neuro-fuzzy system consists of two parts to perform different tasks. One is to discriminate the fault section between overhead and underground using the detailed coefficients obtained by wavelet transform. The other system calculates fault location. The algorithm for fault location again is divided into two parts: one to calculate the fault location on the overhead lines, the other one for the underground cable section. This system shows excellent results for discrimination of fault section and calculation of fault location. (c) 2006 Elsevier Ltd. All rights reserved
    88.   Bhalja, B., Maheshwari, R.P., 2007. Percentage differential protection of double-circuit line using wavelet transform. Electric Power Components and Systems 35, 945-954.
Abstract: This article presents development of a new percentage differential protection scheme for double- circuit transmission line using wavelet transform (WT). The work presented addresses the problems encountered by conventional distance relays when protecting double- circuit transmission lines sharing the same right of way. By the use of powerful analyzing and decomposing features of WT, a new technique is presented that takes care of the problems faced by pilot independent distance relay. The suggested technique depends on the six line currents of the two parallel lines at each end. The idea of the protection algorithm is based on the percentage of the difference of the two line current of each corresponding phase at each terminal. The measured six line currents at the relay location are decomposed into three levels of decomposition using the db4 mother wavelet. The summation of third level approximation coefficients are used as bias current whereas third level detailed coefficients are used as differential current. The proposed method eliminates many of the problems associated with double- circuit lines, such as high fault resistance, cross- country fault, mutual coupling effects, remote infeed, and avoids the problem of single- end supply. The stability of the relay under varied system configurations and operating conditions is examined. The relay algorithm is tested for various probable fault inception angles and loading conditions and with varying fault resistance between 0-150 ohms. The proposed wavelet based scheme provides encouraging results for different fault and system conditions. Relaying signals under different fault conditions were obtained by simulating the system using PSCAD/EMTDC
    89.   Radojevic, Z., Terzija, V., 2007. Effective two-terminal numerical algorithm for overhead lines protection. Electrical Engineering 89, 425-432.
Abstract: In the paper an effective numerical algorithm for overhead lines protection, particularly fault location and adaptive autoreclosure, is presented. It is based on the two terminal line currents and voltages acquisition. For this purposes the synchronized sampling of all analogue input variables, i.e. the application of the Global Position System/Phasor Measurement Units, was assumed. The algorithm presented is derived in the spectral domain. By this the set of third harmonics variables and line parameters was also used. The prerequisite for successfully adaptive autoreclosure functionality realization was the suitable modelling of the electrical arc. Arc was considered as a source of higher harmonics, distorting by this other electrical variables. In the arc modelling, results of laboratory testing were used. Algorithm is tested for a typical network configuration, assuming by this that the line considered was short enough to neglect its capacitive nature. Based on the results obtained, it is very realistic that the algorithm presented could be implemented in praxis in modern Intelligent Electronic Devices (IEDs)
    90.   Wang, C., Dou, C.X., Li, X.B., Jia, Q.Q., 2007. A WAMS/PMU-based fault location technique. Electric Power Systems Research 77, 936-945.
Abstract: A WAMS (wide-area measurement/monitoring system)/PMU (phasor measurement unit)-based fault location technique is proposed in this paper. The technique uses synchronized fault voltages of two nodes of the faulted line and their neighboring nodes for fault location. Based on these fault node voltages measured by PMUs, line currents between these nodes can be calculated. Then, node injection currents at two terminals of the faulted line are formed from the line currents. Based on the calculated fault node injection currents, fault node can be deduced or fault location in transmission lines can be calculated accurately. Fault location formulas are derived in full details. Case studies on IEEE-14-bus system and a testing network with 500 kV transmission lines including ATP/EMTP simulations are given to validate the proposed technique. Various fault types and fault resistances are also considered. (c) 2006 Elsevier B.V. All rights reserved
    91.   Radojevic, Z., Terzija, V., 2007. Numerical algorithm for overhead lines protection and disturbance records analysis. Iet Generation Transmission & Distribution 1, 357-363.
Abstract: A new and very efficient numerical algorithm for overhead lines protection is presented. The algorithm particularly improves up-to-date solutions with regard to fault location, adaptive autoreclosure, detailed disturbance records analysis and fault data management. It is based on the two-terminal line currents and voltages acquisition. For this purpose, the synchronised sampling of all analogue input variables, that is, the application of the global positioning system/phasor measurement units, was assumed. The algorithm presented is derived in the spectral domain and based on the application of the discrete Fourier transform. The prerequisite for the successful adaptive autoreclosure functionality realisation was the suitable modelling of the electrical are. The electrical arc was considered as a source of higher harmonics. These are included in the complete fault model, which was the starting point for the development of this new algorithm. One of the algorithm's sophisticated features is its ability to determine both the arc and the fault resistance. For the purpose of arc modelling, the results of high current laboratory testing are used. The algorithm is tested through computer-based simulation of a line connected to two active networks. On the basis of the results obtained, it is very realistic that the algorithm presented could be implemented in praxis in modem intelligent electronic devices
    92.   Vazquez, E., Castruita, J., Chacon, O.L., Conde, A., 2007. A new approach traveling-wave distance protection - Part I: Algorithm. Ieee Transactions on Power Delivery 22, 795-800.
Abstract: This paper describe a new ultra-high speed protection algorithm for traveling-wave distance protection for transmission lines, based on pattern recognition of the first wavefront that arrives at the relay location due to fault. The algorithm uses principal component analysis (PCA) to preprocess data from the power system in order to eliminate redundant information and enhance hidden patterns in the traveling waves for internal and external faults. The algorithm was proven using PSCAD/EMTDC simulations in a three-phase 400-kV power system considering critical fault cases. The results show the feasibility to implement this algorithm for transmission-line ultra-high speed protection
    93.   Pereira, C.E.D., Zanetta, L.C., 2007. An optimisation approach for fault location in transmission lines using one terminal data. International Journal of Electrical Power & Energy Systems 29, 290-296.
Abstract: A new algorithm for fault location in transmission lines is presented, using in the calculation of fault distance phasors of voltage and current at one of the line terminals, and also the system equivalents at both line terminals. Through an optimisation process, the proposed method is able to find the fault distance in an accurate approach. A parametric analysis of variables present in the phenomenon is developed, showing the performance of the method for different line fault types. (C) 2006 Published by Elsevier Ltd
    94.   Silveira, E.G., Pereira, C., 2007. Transmission line fault location using two-terminal data without time synchronization. Ieee Transactions on Power Systems 22, 498-499.
Abstract: This letter presents a new transmission line fault location method that uses current and voltage sinusoidal phasors at both ends, without necessity of data synchronization. The main difference among the classical Johns method resides in the fact that the proposed method is based on magnitude of fault point voltage and does not demand exact phase angles of the acquired signals. Simulated and real case results are presented, showing that the proposed algorithm is robust, accurate, and provides adequate performance. Practical applications confirm that the synchronization is not really necessary, making the method faster and easier to apply than classical methods in many real situations
    95.   Radojevic, Z.M., 2007. A new spectral domain approach to the distance protection, fault location and arcing faults recognition on transmission lines. International Journal of Electrical Power & Energy Systems 29, 183-190.
Abstract: In this paper, a novel two-stage numerical algorithm devoted to fault distance calculation and arcing faults recognition is presented. The first algorithm stage serves for the fault distance calculation. Fault distance is calculated from the fundamental frequency phase voltages and currents phasors, utilizing the positive- and zero-sequence impedance of the line as an input parameter. The second algorithm stage serves for the arc-voltage amplitude calculation. It utilizes the fault distance obtained from the first algorithm stage and the third harmonics of the terminal phase voltages and line currents phasors as input parameters. From the calculated value of arc-voltage amplitude it can be concluded if the fault is transient arcing fault or permanent arcless fault. The phasors needed for algorithm development are calculated by using Discrete Fourier Technique. In the paper the solution for the most frequent phase-to-ground faults is given. The results of algorithm testing through computer simulation and real field record are given. (C) 2006 Elsevier Ltd. All rights reserved
    96.   Jung, H.S., Park, Y., Han, M., Lee, C., Park, H., Shin, M., 2007. Novel technique for fault location estimation on parallel transmission lines using wavelet. International Journal of Electrical Power & Energy Systems 29, 76-82.
Abstract: In this paper, the novel technique for fault location has been investigated on parallel transmission lines using wavelet. Using this technique, we propose two parts for accurate, rapid fault detection and fault location estimation regardless of mutual coupling between parallel lines. The first part is fault detection and extraction of the fundamental signal using wavelet transform. The second part is fault location estimation using least square error method independent of fault resistance, and the remote in feed, etc. The results of extensive simulation showed that it successfully protected the parallel transmission line compared to the traditional techniques more quickly and reliably. (c) 2006 Elsevier Ltd. All rights reserved
    97.   Liao, Y., Elangovan, S., 2006. Unsynchronised two-terminal transmission-line fault-location without using line parameters. Iee Proceedings-Generation Transmission and Distribution 153, 639-643.
Abstract: The paper presents a new two-terminal transmission-line fault-location algorithm without requiring line parameters. The voltage and current measurements at both ends of a transmission line during a fault are assumed to be available and no synchronisation of the data is required. The proposed algorithm is suitable for estimating the location of asymmetric faults on a line when line parameters are not available. Evaluation studies using both simulated and field data are reported
    98.   Zhang, N., Kezunovic, M., 2007. A real time fault analysis tool for monitoring operation of transmission line protective relay. Electric Power Systems Research 77, 361-370.
Abstract: This paper proposes an integrated real time fault analysis tool for transmission line. The two primary techniques used in the fault analysis tool, fuzzy adaptive resonance theory (ART) neural network and synchronized sampling, can offer accurate fault detection, classification, internal/external fault differentiation, and fault location. The paper makes several extensions of the two techniques so that they can fit well in the realistic situations. The hardware configuration and software implementation are proposed in the paper. A comprehensive evaluation study is implemented to compare the proposed fault analysis tool with the traditional distance relay. Simulation results indicate that the integration exemplifies the advantages of both techniques and that the integrated solution has much better performance in different system conditions compared to distance relay. Both dependability and security of transmission line protection system are improved by using the proposed tool. (C) 2006 Elsevier B.V. All rights reserved
    99.   Gomez, J.C., Morcos, M.M., 2007. Letter to the Editor: Inclusion of sensitive equipment immunity in the overcurrent protection of transmission and sub-transmission systems. Electric Power Components and Systems 35, 239-243.
Abstract: Nearly 80% of customer complaints about power quality (PQ) are related to voltage sags. Voltage sags due to short-circuit faults are detected and their effect is detrimental hundreds of miles away from the fault location. Overcurrent protection must be done taking PQ issues into account. By transforming the voltage/time immunity curve into a current/time curve it can be coordinated with the normal time/current characteristic (TCC) of protective devices. Having the SE immunity curve, the TCC of protective devices, and the fault occurrence index, a complete evaluation of the whole power-quality and overcurrent-protection interaction can be assessed
  100.   Liao, Y., 2006. Fault location utilizing unsynchronized voltage measurements during fault. Electric Power Components and Systems 34, 1283-1293.
Abstract: Diverse transmission line fault location methods have been proposed utilizing voltages and currents as inputs. This article develops several algorithms utilizing only the voltages, dispensing with current transformers and thus eliminating the errors caused by saturation of current transformers. The algorithms are applicable to line to ground faults, line to line faults, and line to line to ground faults. The algorithms utilize unsynchronized fault voltage measurements from two ends of a line and do not require pre-fault data. Shunt capacitances of the line are fully considered. Encouraging results have been obtained by simulation studies
  101.   Lee, C.J., Park, J.B., Shin, J.R., Radojevie, Z.M., 2006. A new two-terminal numerical algorithm for fault location, distance protection, and arcing fault recognition. Ieee Transactions on Power Systems 21, 1460-1462.
Abstract: This letter presents a new numerical algorithm for fault location calculation and arcing faults recognition. The proposed algorithm is based on the synchronized phasors measured from the phasor measurement units (PMUs) installed at both terminals of the transmission lines. From the calculated are voltage amplitude, a decision can be made whether the fault is permanent or transient. The proposed algorithm is tested through computer simulations to show its effectiveness
  102.   Lien, K.P., Liu, C.W., Yu, C.S., Jiang, J.A., 2006. Transmission network fault location observability with minimal PMU placement. Ieee Transactions on Power Delivery 21, 1128-1136.
Abstract: This paper presents a concept of fault-location observability and a new fault-location scheme for transmission networks based on synchronized phasor measurement units (PMUs). Using the proposed scheme, minimal PMUs are installed in existing power transmission networks so that the fault, if it occurs, can be located correctly in the network. The scheme combines the fault-location algorithm and the fault-side selector. Extensive simulation results verify the proposed scheme
  103.   Brahma, S.M., 2006. New fault-location method for a single multiterminal transmission line using synchronized phasor measurements. Ieee Transactions on Power Delivery 21, 1148-1153.
Abstract: This paper describes a new iterative method to locate a fault on a single multiterminal transmission line. The method uses synchronized voltage and current measurements from all terminals. Using positive-sequence components of the prefault and postfault waveforms, positive-sequence source impedances are estimated. Using these source impedances and the line data, the positive-sequence bus impedance matrix (Z(bus)) is formed. Using the properties of Z(bus), an iterative algorithm is proposed. The algorithm first identifies the faulted section and then locates the fault on this section. This algorithm is applied to the data obtained from the Electromagnetic Transients Program simulation of a multiterminal transmission fine. The simulation results show that the distinctive features of this method are that it performs with very high accuracy for all types of faults at different fault locations and is practically immune to fault resistance
  104.   Radojevic, Z.M., Shin, J.R., 2006. New one terminal digital algorithm for adaptive reclosing and fault distance calculation on transmission lines. Ieee Transactions on Power Delivery 21, 1231-1237.
Abstract: This paper presents a new numerical spectral domain algorithm devoted to blocking unsuccessful automatic reclosing onto permanent faults and fault distance calculation. Are voltage amplitude and fault distance are calculated from the fundamental and third harmonies of the terminal voltages and currents phasors. The electric arc is modeled with its voltage waveshape defined numerically on the basis of a number of arc voltage records obtained in the high-voltage laboratory. From the calculated arc voltage amplitude, it can be concluded whether the fault is a transient arcing fault or a permanent arcless fault. If the fault is permanent, automatic reclosure should be blocked. The algorithm can be applied for adaptive autoreclosure, distance protection, and fault location. The results of algorithm testing through computer simulation and real field record are given
  105.   Shwehdi, M.H., 2006. Reliable maps of lightning thunderstorms for Saudi Arabia. Ieee Transactions on Power Delivery 21, 1571-1577.
Abstract: The main objective of this research is to. develop reliable maps of isokeraunic level (thunderdays/year, TD) for the country on annual and seasonal bases. New annual thunder day maps for Saudi Arabia are presented. The results in this paper are based on data and records of thunderstorm incidences in Saudi Arabia recorded by the Presidency of Metrology and Environment. These are compared with data from power system fault records and with NASA satellite data. These new maps indicate the location, frequency, and intensity of thunderstorms. Such information is useful for engineers concerned with the design and operation of transmission and distribution lines in the country, and for the more general design of lightning protection. systems. Thunderstorms are most frequent in the southwest mountains in the country, reaching a maximum TD of 97; the average TD for the whole country is 26
  106.   Udo, T., 2006. Study of the winter lightning ground flash density investigated by the lightning location systems. Ieee Transactions on Power Delivery 21, 1613-1619.
Abstract: A network of lightning location systems covering the entire Japanese Archipelago has been operational since the late 1980s. However, the operational records appear to be distorted relative to winter lightning flash densities. The maximum flash density registered was 0.3 flashes/km(2) per one winter season, a mere one-tenth of the corresponding figure for severe summer lightning anywhere along the archipelago. On the other hand, the fault frequencies of overhead transmission lines constructed in the severe winter lightning districts are comparable with those of severe summer lightning districts. The author submits to resolve the apparent disparity by introducing two analytical parameters, namely 1) the propagation velocity of the return strokes of the winter lightning, and 2) the seasonal difference in the altitude of the lightning charge in the cloud. Consequently, the author proposes a certain seasonal modification of the threshold level applicable to the operation of lightning location systems
  107.   Spoor, D., Zhu, H.G., 2006. Improved single-ended traveling-wave fault-location algorithm based on experience with conventional substation transducers. Ieee Transactions on Power Delivery 21, 1714-1720.
Abstract: Single-ended unsynchronized traveling-wave fault-location algorithms have been around for several years. They avoid the costs and complexities associated with remote-end, synchronization. Nevertheless, there is a corresponding increase in required signal processing as each reflection must be identified and then related in time to the signal wavefront. The current signal processing techniques include a combination of modal and wavelet analysis, where the resulting vectors are often squared. However, the performance of this process degrades dramatically with the filtering associated with the substation transducers and secondary circuits. Furthermore, the variation in observed reflection patterns demonstrates that these methods cannot adequately distinguish between faults on the near, or far half of the transmission line. This paper considers the traveling-wave data observed on a 330-kV transmission system and presents a new signal processing methodology to cater for the observations. This is based on the continuous wavelet transform that is calculated at a suitably large scale. The polarities of the resulting coefficients are used to confirm the nature of the fault and to infer the true fault location
  108.   Zhang, J.F., Smith, J.S., Wu, Q.H., 2006. Morphological undecimated wavelet decomposition for fault location on power transmission lines. Ieee Transactions on Circuits and Systems I-Regular Papers 53, 1395-1402.
Abstract: This paper presents a novel morphological undecimated wavelet (MUDW) decomposition scheme for fault location on power transmission lines. The MUDW scheme is developed based on the morphological wavelet (MW) theory for both the extraction of transient features and noise reduction in signal processing. The analysis operators and the synthesis operator of MUDW strictly satisfy the pyramid condition. In this paper, the MUDW scheme is used to extract features from noise imposed fault-generated transient voltage and/or current signals of power transmission lines. The efficiency of the MUDW scheme used for noise reduction and the extraction of sudden changes in the transient signals are evaluated in simulation studies. The simulation results show that the fault location can be accurately detected in noisy environments
  109.   El Din, E.S.T., Aziz, M.M.A., Ibrahim, D.K., Gilany, M., 2006. Fault location scheme for combined overhead line with underground power cable. Electric Power Systems Research 76, 928-935.
Abstract: This paper presents a fault location scheme for transmission systems consisting of an overhead line combined with an underground power cable. The algorithm requires phasor measurements data from one end of the transmission line and the synchronized measurements at the most far end of the power cable. Fault location is derived using distributed line model, modal transformation theory and Discrete Fourier Transform. The technique can be used on-line or off-line using the data stored in the digital fault recording apparatuses. The proposed scheme has the ability to locate the fault whether it is in the overhead line or in the underground power cable. In addition to, the proposed scheme gives an accurate estimation of the fault resistance at fault location. Extensive simulation studies carried out using MATLAB show that the proposed scheme provides a high accuracy in fault location under various fault conditions. (c) 2006 Elsevier B.V. All rights reserved
  110.   Jiale, S., Song, G.B., Xu, Q.Q., Chao, Q., 2006. Time-domain fault location algorithm for parallel transmission lines using unsynchronized currents. International Journal of Electrical Power & Energy Systems 28, 253-260.
Abstract: Parallel transmission lines under fault can be decoupled into common component net and differential component net. For the differential component net is only composed by parallel lines part and its bus voltages are zero, the voltage distributions along differential component net can be calculated by each terminal current. The novel time-domain fault location algorithm is founded by voltage distributions from both terminals have the least difference at the fault point. The synchronization is achieved by searching the minimal value of locating criterion function, which is calculated by fixing one terminal data and moving another terminal data within a setting time. The proposed algorithm needs a very short data-window, any segment of fault data front transient to steady state can be used to locate faults, and no voltage data is needed. With distributed parameter model, simulations show that the locating errors are less than 0.1 km, and the fault types and fault resistances have no effect on locating accuracy. (C) 2005 Elsevier Ltd. All rights reserved
  111.   Samantaray, S.R., Dash, P.K., Panda, G., 2006. Fault classification and location using HS-transform and radial basis function neural network. Electric Power Systems Research 76, 897-905.
Abstract: A new approach for protection of transmission lines has been presented in this paper. The proposed technique consists of preprocessing the fault current and voltage signal sample using hyperbolic S-transform (HS-transform) to yield the change in energy and standard deviation at the appropriate window variation. After extracting these two features, a decision of fault or no-fault on any phase or multiple phases of the transmission line is detected, classified, and its distance to the relaying point found out using radial basis function neural network (RBFNN) with recursive least square (RLS) algorithm. The ground detection is done by a proposed indicator 'index'. As HS-transform is very less sensitive to noise compared to wavelet transform, the proposed method provides very accurate and robust relaying scheme for distance protection. (C) 2005 Elsevier B.V. All rights reserved
  112.   Okuyama, K., Kato, T., Suzuoki, Y., Funabashi, T., 2006. Protection relay system using information network for distribution system with DGs. Electrical Engineering in Japan 155, 30-35.
Abstract: We propose a new protection scheme for selective and quick disconnection of a fault area in a distribution system, which can be flexibly adopted for a large-scale introduction of distributed generators (DGs). When a fault Occurs, relays provide a binary state signal which is activated if, for instance, the current at the corresponding relay location exceeds a certain value. Although each relay cannot locate (he fault point with only its own signal, it can locate the fault by utilizing signals from other relays together with its own signal. Because only a binary state signal is transmitted instead of the actual physical variable Such as the magnitude of the fault current, the network traffic is much less than when a conventional protection scheme for a transmission system using an information system is applied to a distribution system. The following are the main results of a simulation on our proposed protection scheme: (1) the proposed protection scheme can successfully disconnect only a fault feeder when the relays use signals provided from the sending end of (lie fault feeder and all other DGs on the same feeder, (2) in the case of a fault on a DG connected feeder, the DG can be disconnected within 0.06 s. (C) 2006 Wiley Periodicals, Inc
  113.   Izykowski, J., Molag, R., Rosolowski, E., Saha, M.M., 2006. Accurate location of faults on power transmission lines with use of two-end unsynchronized measurements. Ieee Transactions on Power Delivery 21, 627-633.
Abstract: This paper presents a new algorithm for locating faults on two-terminal power transmission lines. Unsynchronized two-end voltages and currents are processed for determining the sought distance to fault and the synchronization angle. The calculations are performed initially for the lumped model of a transmission line. Then, these results are used as the initial data for the Newton-Raphson method-based iterative calculations, in which the distributed parameter line model is utilized. The delivered fault location algorithm has been tested and evaluated with the fault data obtained from versatile ATP-EMTP simulations. The sample results of the evaluation are reported and discussed
  114.   Radojevic, Z.M., Terzija, V.V., 2006. Two-stage numerical algorithm for distance protection, fault location and arcing faults recognition. Electrical Engineering 88, 289-295.
Abstract: In this paper, a novel two-stage numerical algorithm devoted to fault distance calculation and arcing faults recognition is presented. The first algorithm stage serves for the fault distance calculation. The fault distance is calculated from the fundamental frequency phase voltages and current phasors, thus utilizing the positive- and the zero-sequence impedances of the line as input parameters. The second algorithm stage serves for the arc voltage amplitude calculation. It utilizes the fault distance calculated in the first algorithm stage as well as the third harmonics of the terminal phase voltage and line current phasors, respectively. From the calculated value of arc voltage amplitude it can be determined whether the fault is transient arcing fault or permanent arcless fault. The phasors needed for algorithm execution are calculated by using the Discrete Fourier Technique. In this paper, the solution for the most frequent phase-to-ground faults is given. The results of algorithm testing through computer simulation and real field data records processing are given
  115.   Suonan, J.L., Qi, J., 2005. An accurate fault location algorithm for transmission line based on R-L model parameter identification. Electric Power Systems Research 76, 17-24.
Abstract: An accurate time domain algorithm for fault location using one-terminal data is presented. The algorithm is based on the modal analysis and the R-L model of transmission lines, and utilizes the fault-superimposed components effectively. In the algorithm, the differential equations of fault condition networks and pure-fault networks are combined to determine the fault distance. The fault distance, fault resistance and source parameters at the remote end are solved as the unknown variables of a second-order system by finite difference method. This algorithm eliminates influence of the fault resistance and the opposite source parameters on the fault location accuracy, which have been the main source of error for conventional one-terminal approaches. In addition, the paper discusses manipulations of equations to solvable form and the minimum number of equations required. By the analysis to the correlation of measurement equations and the analytic solution of the fault current and voltage in time domain, the paper demonstrates that one-terminal algorithm has the same precision as two-terminal algorithm in theory. The EMTP simulation results show the validity and high accuracy of the new algorithm. (C) 2005 Elsevier B.V. All rights reserved
  116.   Al-Dabbagh, M., Kapuduwage, S.K., 2005. Using instantaneous values for estimating fault locations on series compensated transmission lines. Electric Power Systems Research 76, 25-32.
Abstract: Fault location estimation hitherto is based on using the filtered rms values from both ends of the line. In this paper, a new method for locating faults on series compensated high voltage transmission lines, based on the instantaneous values is proposed. Based on the results achieved with the algorithm previously published, using instantaneous values, the distance to fault location is estimated very accurately. However, the accuracy of the fault location is limited to the ability to capture data samples before the operation of the metal oxide varistor (MOV). The proposed algorithm incorporates special techniques to avoid the limitation caused by the operation of MOV. It is formal that although the accuracy of fault location using the algorithm proposed is slightly reduced, but still acceptable. This paper describes the new algorithm and examines its accuracy as compared to the paper previously published by these authors. (C) 2005 Elsevier B.V. All rights reserved
  117.   Samantaray, S.R., Dash, P.K., Panda, G., Panigrahi, B.K., 2005. Distance protection of compensated transmission line using computational intelligence. Computational Intelligence and Security, Pt 1, Proceedings 3801, 163-169.
Abstract: A new approach for protection of transmission line including TCSC is presented in this paper. The proposed method includes application of Fuzzy Neural Network for distance relaying of a transmission line operating with a thyristor controlled series capacitor (TCSC) protected by MOVs. Here the fuzzy neural network (FNN) is used for calculating fault location on the TCSC line. The FNN structure is seen as a neural network for training and the fuzzy viewpoint is utilized to gain insight into the system and to simplify the model. The number of rules is determined by the data itself and therefore, a smaller number of rules are produced. The network parameters are updated by Extended Kalman Filter (EKF) algorithm. with a pruning strategy to eliminate the redundant rules and fuzzification neurons resulting in a compact network structure. The input to the FNN are fundamental currents and voltages at the relay end, sequence components of current, system frequency and the firing angle with different operating conditions and the corresponding output is the location of the fault from the relaying point The location tasks of the relay are accomplished using different FNNs for different types of fault (L-G,LL-G,LL, LLL)
  118.   Gracia, J., Mazon, A.J., Zamora, I., 2005. Best ANN structures for fault location in single-and double-circuit transmission lines. Ieee Transactions on Power Delivery 20, 2389-2395.
Abstract: The great development in computing power has allowed the implementation of artificial neural networks (ANNs) in the most diverse fields of technology. This paper shows how diverse ANN structures can be applied to the processes of fault classification and fault location in overhead two-terminal transmission lines, with single and double circuit. The existence of a large group of valid ANN structures.guarantees the applicability of ANNs in the fault classification and location processes. The selection of the best ANN structures for each process has been carried out by means of a software tool called SARENEUR
  119.   Song, G.B., Suonan, J., Xu, Q.Q., Chen, P., Ge, Y.Z., 2005. Parallel transmission lines fault location algorithm based on differential component net. Ieee Transactions on Power Delivery 20,  2396-2406.
Abstract: This paper presents a novel time-domain fault location algorithm for parallel transmission lines using two terminal currents. Parallel transmission lines with faults can be decoupled into the common component net and differential component net. Since the differential component net is only composed of the parallel lines and its terminal voltages equal zero, the proposed algorithm is based on the fact that the difference between voltage distributions, calculated from two terminal currents, is the smallest at fault point. To be practical, unsynchronized data ' and the-transient transferring ability of the current transformer are taken into consideration. The algorithm needs a very short data window, and any segment of current data can be used to locate faults. The proposed algorithm is verified successfully using the simulation data generated by the frequency-dependent line model of the Alternative Transients Program and the field recording data provided by traveling-wave fault locators. Locating results show the satisfactory accuracy of the algorithm for various fault types, fault distances, and fault resistances
  120.   Pathirana, V., McLaren, P.G., 2005. A hybrid algorithm for high speed transmission line protection. Ieee Transactions on Power Delivery 20, 2422-2428.
Abstract: A common method used in UHV transmission line protection is based on impedance measurement technique. The fault detection speed of impedance protection schemes cannot be improved without sacrificing the relay reach limit. Protection algorithms based on fault generated transient signals have shown promising results in improving the speed, but these methods have inherent reliability problems. This paper examines how the fault generated transient information can be used to achieve fast fault detection speeds in a distance protection scheme while maintaining a high reliability level
  121.   Cerri, G., De Leo, R., Della Nebbia, L., Pennesi, S., Primiani, V.M., Russo, P., 2005. Fault location on shielded cables: Electromagnetic modelling and improved measurement data processing. Iee Proceedings-Science Measurement and Technology 152, 217-226.
Abstract: This paper analyses the performance of the time domain reflectometry (TDR) technique when it is applied to the location of faults on cables. Different types of defects, which can arise on coaxial cables, are modelled and their reflection coefficients are calculated. The results, validated by experimental data, are compared to the typical noise that affects this kind of measurement to assess the sensitivity of the technique. Shield damage to a shielded twisted pair and a shielded multiwire cable is also examined: these examples represent more critical situations because the effect of cable and mismatching losses limits the dynamic range of the measurement. In both cases, the TDR allows us to locate faults that strongly affect the propagation of the signal on the transmission line, but the reflections produced by small defects are often masked by the noise. A data processing technique based on the comparison with a reference measurement and the use of the statistical correlation are then implemented. In this way, the reflections produced by the faults are much more visible and an overall enhancement of the technique sensitivity is achieved
  122.   Yoon, C.D., Lee, S.Y., Shin, M.C., Jung, H.S., Cha, J.S., 2005. A fault distance estimation method based on an adaptive data window for power network security. Computational Science and Its Applications - Iccsa 2005, Pt 2 3480, 332-340.
Abstract: This paper presents a rapid and accurate algorithm for fault location estimation in a power transmission line. This algorithm uses the least square error (LSE) method for fault impedance estimation. After interrupting a fault, an adaptive data window technique using LSE estimates the fault impedance. Since it changes its data length according to the convergence degree of fault impedance, it can find an optimal data window length and estimate fault impedance rapidly. To prove the performance of the algorithm, the authors have tested relaying signals obtained from EMTP simulation. Test results show that the proposed algorithm estimates fault location by calculating fault impedance within a half cycle of the fault, regardless of fault type and various fault conditions. Compared to traditional techniques, it can protect parallel transmission lines more quickly and reliably
  123.   Gohokar, V.N., Khedkar, M.K., 2005. Faults locations in automated distribution system. Electric Power Systems Research 75 , 51-55.
Abstract: This paper presents new techniques for locating short circuit and open conductor faults on automated distribution system. This is a unique method where short circuit and open conductor faults are treated simultaneously. The proposed fault location scheme is capable of accurately identifying the zone in which fault occurs. Temporary faults are also detected which may not result in a blown fuse. Data is made available to the substation remote terminal unit from various automated distribution system equipments. Decision is taken based upon the magnitude of fundamental frequency component of voltage and current phasor. Testing of proposed fault location method has been demonstrated on the laboratory model for its practical use. Analogues simulation results are obtained using electromagnetic transients program (EMTP). (c) 2005 Published by Elsevier B.V.
  124.   Holbert, K.E., Heydt, G.T., Ni, H., 2005. Use of satellite technologies for power system measurements, command, and control. Proceedings of the Ieee 93, 947-955.
Abstract: This paper analyzes the use of wide-area measurement technologies including satellite-based methods for the command and control of power systems. The methods studied include the global positioning system (GPS) and low earth orbit satellites (LEOS). Satellite technologies have been used in a variety of applications requiring precise timing between geographically diverse locations. The deregulation of the electric power industry is placing increased demands on power transmission system utilization. Because deregulated power systems utilize long-distance high-power exchanges, satellite-based communication systems are useful in control of geographically large interconnected power systems. In this paper the satellite-based measurements and commands are introduced for wide-area control. With the support of wide-area signals, a multiagent supervisory-level power system stabilizer is proposed here as a potential wide-area control structure. Increased loading of transmission facilities is an impetus for accurate dynamic thermal overhead electrical conductor ratings. The application of satellite-based measurement for improving the dynamic thermal rating of overhead transmission circuits is suggested
  125.   Ji, Z., Li, H.H., Li, Q., Wu, Q.H., 2005. Fault location in power transmission lines using adaptive lifting scheme. Electronics Letters 41, 440-441.
Abstract: A novel adaptive lifting scheme is proposed to effectively extract features of fault-generated high-frequency transient waveforms in power transmission lines. The accurate and fast fault location is achieved
  126.   Pereira, C.E.D., Zanetta, L.C., 2005. Optimization algorithm for fault location in transmission lines considering current transformers saturation. Ieee Transactions on Power Delivery 20, 603-608.
Abstract: This paper deals with fault location calculations that use voltages and currents during transient conditions and pre fault values. The method uses transmission line measurements at both terminals and its main contribution is the possibility of fault location even with the lack of some current measurements as in the case of current transformers saturation or even when data acquisition process fails. The equations are based on two-port line representation that can be applied to transposed or untransposed lines and equivalent impedances at the terminals are not needed. With the proposed formulation, the algorithm does not use simplifying assumptions to calculate the fault distance and the fault resistance simultaneously. For phase-to-ground faults, the possibility of lack of accurate current measurement in one CT is assumed. For double phase-to-ground faults and three phase faults, the lack of measurements in two or three CTs, respectively, is also assumed. The results, considering different line configurations and fault types, are presented, showing the accuracy and efficiency of the proposed method
  127.   Das, B., Reddy, J.V., 2005. Fuzzy-logic-based fault classification scheme for digital distance protection. Ieee Transactions on Power Delivery 20, 609-616.
Abstract: In this paper, a fuzzy-logic-based algorithm to identify the type of faults for digital distance protection system has been developed. The proposed technique is able to accurately identify the phase(s) involved in all ten types of shunt faults that may occur in a transmission line under different fault resistances, inception angle, and loading levels. The proposed method needs only three line-current measurements available at the relay location and can perform the fault classification task in about a half-cycle period. Thus, the proposed technique is well suited for implementation in a digital distance protection scheme
  128.   Evrenosoglu, C.Y., Abur, A., 2005. Travelling wave based fault location for teed circuits. Ieee Transactions on Power Delivery 20, 1115-1121.
Abstract: This paper describes a fault location algorithm for three terminal lines using wavelet transform of the fault initiated transients. The results presented in [1] are extended to the case of three terminal configuration and a new single ended procedure is developed for teed circuits. The algorithm gives accurate results for the case of three terminal lines including series compensated branch, mutual coupled line section and different values of fault resistances. The performance of the algorithm is tested on different scenarios by using ATP/EMTP program and MATLAB Wavelet Toolbox
  129.   Brahma, S.M., 2005. Fault location scheme for a multi-terminal transmission line using synchronized voltage measurements. Ieee Transactions on Power Delivery 20, 1325-1331.
Abstract: This paper describes a new scheme to locate a fault on a multi-terminal transmission line. It describes a simple new algorithm to identify the faulted section first. Then, to exactly locate the fault on this section, a method is described that uses the synchronized voltage measurements at all terminals. The main advantage of this method is that the current-transformer errors in the current measurements can be avoided. Since these errors can be as high as 10%, the fault location is extremely accurate with this method. The scheme can work for transposed as well as untransposed lines and is free of prefault conditions. The paper, after describing the scheme, describes very promising results from an Electromagnetic Transients Program simulation of a multi-terminal transmission line
  130.   Shi, W., Li, F., Han, Y.H., Li, Y.G., 2005. The effect of ground resistance on secondary arc current on an EHV transmission line. Ieee Transactions on Power Delivery 20, 1502-1506.
Abstract: After a single-phase-to-ground fault occurs on an extremely-high-voltage transmission line, the duration of the secondary arc mainly depends on the magnitude of the secondary, which is determined by the ground resistance and the system's equivalent impedance at the fault location. In this paper, analytical formulas for calculating them system's equivalent impedance have been developed for three different arc-extinguishing techniques. These formulas show a satisfactory accuracy in comparison with electromagnetic transient program (EMTP) simulations. Then, the effect of the ground resistance on the secondary arc current has been evaluated by comparing it with the system's equivalent impedance., The resistance hardly influences the secondary arc current when no arc-extinguishing facility is adopted or when four-reactor banks are employed; while the resistance significantly affects the current when high-speed, grounding switches are used
  131.   Martins, L.S., Martins, J.F., Pires, V.F., Alegria, C.M., 2005. A neural space vector fault location for parallel double-circuit distribution lines. International Journal of Electrical Power & Energy Systems 27, 225-231.
Abstract: A new approach to fault location for parallel double-circuit distribution power lines is presented. This approach uses the Clarke-Concordia transformation and an artificial neural network based learning algorithm. The a, 0, 0 components of double line currents resulting from the Clarke-Concordia transformation are used to characterize different states of the system. The neural network is trained to map the non-linear relationship existing between fault location and characteristic eigenvalue. The proposed approach is able to identify and to locate different types of faults such as: phase-to-earth, phase-to-phase, two-phase-to-earth and three-phase. Using the eigenvalue as neural network inputs the proposed algorithm locates the fault distance. Results are presented which shows the effectiveness of the proposed algorithm for a correct fault location on a parallel double-circuit distribution line. (C) 2004 Elsevier Ltd. All rights reserved
  132.   Moon, H.K., Hyun, S.H., Lee, S.J., 2005. A new distance relaying method with system load condition considered in a transmission line. On the Convergence of Bio-Information-, Environmental-, Energy-, Space- and Nano-Technologies, Pts 1 and 2 277-279, 686-691.
Abstract: This paper presents a novel fault location algorithm for a distance relay of a transmission line. Under the assumption that the source voltages and impedances of both ends are not changed before and after a fault, the fault current and the voltage of the terminal end are estimated including the loading condition. Then, the fault location expression, independent of the fault resistance, is derived using these voltages and currents through a loop analysis, in the manner that the in-feed effect of the terminal end is eliminated. The suggested algorithm is applied to a typical transmission line to show its effectiveness
  133.   Tawfik, M.M., Morcos, M.M., 2005. On the use of prony method to locate faults in loop systems by utilizing modal parameters of fault current. Ieee Transactions on Power Delivery 20, 532-534.
Abstract: A method utilizing prony algorithm and artificial neural networks (ANNs) is presented to locate faults on loop systems. Fault simulation is implemented using the ATP-EMTP. The loop system is represented by a line with generator units on both ends. The proposed method accounts for the anticipated changes in the traveling-wave characteristics. Proposed modifications are limited to the type of ANN inputs. The modified scheme provided good accuracy in locating the faults
  134.   Lin, Y.H., Liu, C.W., Chen, C.S., 2004. A new PMU-based fault detection/location technique for transmission lines with consideration of arcing fault discrimination - Part I: Theory and algorithms. Ieee Transactions on Power Delivery 19, 1587-1593.
Abstract: A new fault detection/location technique with consideration of arcing fault discrimination based on phasor measurement units for extremely high voltage/ultra-high voltage transmission lines is presented in this two-paper set. Part I of this two-paper set is mainly aimed at theory and algorithm derivation. The proposed fault detection technique for both arcing and permanent faults is achieved by a combination of a fault detection index \M\ and a fault location index \D\, which are obtained by processing synchronized fundamental phasors. One is to detect the occurrence of a fault and the other is to distinguish between in-zone and out-of-zone faults. Furthermore, for discriminating between arcing and permanent faults, the proposed technique estimates the amplitude of arc voltage by least error squares method through the measured synchronized harmonic phasors caused by the nonlinear arc behaviour. Then, the discrimination will be achieved by comparing the estimated amplitude of arc voltage to a given threshold value. In addition, in order to eliminate the error caused by exponentially decaying dc offset on the computations of fundamental and harmonic phasors, an extended discrete Fourier transform algorithm is also presented
  135.   Lin, Y.H., Liu, C.W., Chen, C.S., 2004. A new PMU-based fault detection/location technique for transmission lines with consideration of arcing fault discrimination - Part II: Performance evaluation. Ieee Transactions on Power Delivery 19, 1594-1601.
Abstract: The theory and algorithms of the proposed technique have been presented in Part I of this two-paper set. In Part II of this two-paper set, the proposed technique is evaluated by considerable simulation cases simulated by the Matlab/Power system Blockset simulator. For the proposed fault detector, the trip time achieved can be up to 3.25 ins and the average value of trip times is about 8 ins for both permanent and arcing faults on transmission lines. For the proposed fault locator, the accuracy can be up to 99.99% and the error does not exceed 0.45%. Moreover, the proposed arcing fault discriminator can discriminate between arcing and permanent faults within four cycles after fault inception. It has proven to be an effective tool to block reclosing on the permanent faults in the computer simulations. The simulation results also demonstrate that the presented extended discrete Fourier transform algorithm eliminates effectively the error caused by exponentially decaying dc offset on fundamental and harmonic phasor computations. Finally, a test case using the real-life measured data proves the feasibility of the proposed technique
  136.   Brahma, S.M., Girgis, A.A., 2004. Fault location on a transmission line using synchronized voltage measurements. Ieee Transactions on Power Delivery 19, 1619-1622.
Abstract: Many methods for fault location using synchronized phasor measurement have been reported in literature. Most of these methods use voltage and current measurements at one or both ends of a transmission line. Accuracy of current measurement is limited by the accuracy of the current transformers (CT) used. This paper describes a fault-location method for transmission lines using only synchronized voltage measurements at both ends of the line, eliminating the inherent error due to CT. The method can be applied to transposed and untransposed lines. The method is tested using results from a steady state fault-analysis program and EMTP
  137.   Mahanty, R.N., Gupta, P.B.D., 2004. An improved method for digital relaying of transmission lines. Electric Power Components and Systems 32, 1013-1030.
Abstract: A scheme for detection, classification and location of transmission line faults, which combines the wavelet multi-resolution analysis approach and the differential equation approach, is presented. While detection and classification of faults is carried out by a wavelet analysis based algorithm, fault location is determined by a differential equation based algorithm. Using EMTP and MATLAB, studies have been carried out on two simulated power system models. The models are subjected to different types of faults while operating at different operating conditions and the performance of the proposed scheme is evaluated. The results of the simulation studies, which are presented, confirm the feasibility of the proposed scheme
  138.   Joorabian, M., Asl, S.M.A.T., Aggarwal, R.K., 2004. Accurate fault locator for EHV transmission lines based on radial basis function neural networks. Electric Power Systems Research 71, 195-202.
Abstract: This paper describes the design and implementation of an artificial neural networks-based fault locator for extra high voltage (EHV) transmission lines. This locator utilizes faulted voltage and current waveforms at one end of the line only. The radial basis function (RBF) networks are trained with data under a variety of fault conditions and used for fault type classification and fault location on the transmission line. The results obtained from testing of RBF networks with simulated fault data and recorded data from a 400 kV system clearly show that this technique is highly robust and very accurate. The technique takes into account all the practical limitations associated with a real system. Thereby making it possible to effectively implement an artificial intelligence (AI) based fault locator on a real system. (C) 2004 Elsevier B.V. All rights reserved
  139.   Zivanovic, R., 2004. On the use of partially linear model in identification of arcing-fault location on overhead high-voltage transmission lines. International Journal of Bifurcation and Chaos 14, 1975-1985.
Abstract: The task of locating an arcing-fault on overhead line using sampled measurements obtained at a single line terminal could be classified as a practical nonlinear system identification problem. The practical reasons impose the requirement that the solution should be with maximum possible precision. Dynamic behavior of an arc in open air is influenced by the environmental conditions that are changing randomly, and therefore the useful practically application of parametric modeling is out of question. The requirement to identify only one parameter is yet another specific Of this problem. The parameter we need is the one that linearly correlates the voltage samples with the current derivative samples (inductance). The correlation between the voltage samples and the current samples depends on the unpredictable arc dynamic behavior. Therefore this correlation is reconstructed using nonparametric regression. A partially linear model combines both, parametric and nonparametric parts in one model. The fit of this model is noniterative, and provides an efficient way to identify (pull out) a single linear correlation from the nonlinear time series
  140.   Luo, S., Kezunovic, M., Sevick, D.R., 2004. Locating faults in the transmission network using sparse field measurements, simulation data and genetic algorithm. Electric Power Systems Research 71, 169-177.
Abstract: The paper presents a modeling and simulation approach to locate a fault in a transmission network. The basic concept is to match phasors recorded during fault with the corresponding phasors obtained by simulating the same fault. For the simulation, it is necessary to assume a fault location in a power system model, and then carry out short circuit study. The matching degree can be calculated by a pre-set criterion. The operation is repeated till the best match is found. The process of finding the best match is an optimization problem, therefore, the genetic algorithm (GA) is introduced to find the optimal solution. The proposed approach is suitable for situations where only sparsely recorded field data is available. Under such circumstances, the proposed approach can offer more accurate results than other known techniques. (C) 2004 Published by Elsevier B.V
  141.   Salat, R., Osowski, S., 2004. Accurate fault location in the power transmission line using support vector machine approach. Ieee Transactions on Power Systems 19, 979-986.
Abstract: The paper presents a new approach to the location of fault in the high-voltage power transmission line, relying on the application of the support vector machine and frequency characteristics of the measured one-terminal voltage and current transient signals of the system. The extensive numerical experiments performed for location of different kinds of faults of the transmission line have proved very good accuracy of fault location algorithm. The average error of fault location in a 200-km transmission line is below 100 in and the maximum error did not exceed 2 km
  142.   Mahanty, R.N., Gupta, P.B.D., 2004. Aimlication of RBF neural network to fault classification and location in transmission lines. Iee Proceedings-Generation Transmission and Distribution 151, 201-212.
Abstract: The application of radial basis function (RBF) neural networks for fault classification and location in transmission lines is presented. Instantaneous current/voltage samples have been used as inputs to artificial neural networks (ANNs). Whereas, for fault classification, prefault and postfault samples of only the three-phase currents are sufficient, for fault location, postfault samples of both currents and voltages of the three phases are necessary. To validate the proposed approach simulation studies have been carried out on two simulated power-system models: one in which the transmission line is fed from one end and another, in which the transmission fine is fed from both ends. The models are subjected to different types of faults at different operating conditions for variations in fault location, fault inception angle and fault point resistance. The results of the simulation studies which are presented confirm the feasibility of the proposed approach
  143.   Izykowski, J., Rosolowski, E., Saha, M.M., 2004. Locating faults in parallel transmission lines under availability of complete measurements at one end. Iee Proceedings-Generation Transmission and Distribution 151, 268-273.
Abstract: Fault location in parallel transmission lines with availability of complete measurements from one end of the fines is considered. Generalised models of fault loops and faults are used for formulation of the fault location algorithm. The derived algorithm has a very simple first-order formula and does not require knowledge of impedances of the equivalent systems behind the line terminals as well as use of pre-fault measurements. Application of the fault location algorithm to impedance measurement of the adaptive distance protection is considered. An issue of improving the fault location accuracy by compensating for shunt capacitances of the fines is addressed. Results of the evaluation with use of ATP-EMTP simulations are reported and discussed
  144.   Lee, S.J., Choi, M.S., Kang, S.H., Jin, B.G., Lee, D.S., Ahn, B.S., Yoon, N.S., Kim, H.Y., Wee, S.B., 2004. An intelligent and efficient fault location and diagnosis scheme for radial distribution systems. Ieee Transactions on Power Delivery 19, 524-532.
Abstract: In this paper, an effective fault location algorithm and intelligent fault diagnosis scheme are proposed. The proposed scheme first identifies fault locations using an iterative estimation of load and fault current at each line section. Then an actual location is identified, applying the current pattern matching rules. If necessary, comparison of the interrupted load with the actual load follows and generates the final diagnosis decision. Effect of load uncertainty and fault resistance has been carefully investigated through simulation results that turns out to be very satisfactory
  145.   De Pereira, C.E., Zanetta, L.C., 2004. Fault location in transmission lines using one-terminal postfault voltage data. Ieee Transactions on Power Delivery 19, 570-575.
Abstract: A new algorithm for fault location in transmission lines, with fault distance calculation based on steady-state measured phasors in local terminal is presented. For the postfault, only voltage phasors are required, avoiding possible errors due to current transformer saturation; the current phasors are required only in prefault time, when saturation does not occur. The algorithm does not use simplifying hypothesis but requires system equivalent data at both line terminals and the fault classification, considering fault resistance purely resistive. In order to verify the algorithm performance, a parametric analysis of variables that influences short-circuit conditions is developed, including an analysis of remote equivalent setting. The results show that the algorithm is very accurate, even in cases when the remote equivalent is not well fitted
  146.   Choi, M.S., Lee, S.J., Lee, D.S., Jin, B.G., 2004. A new fault location algorithm using direct circuit analysis for distribution systems. Ieee Transactions on Power Delivery 19, 35-41.
Abstract: The unbalanced nature of distribution systems due to single-phase laterals and loads gives difficulty in the fault location. This paper proposes a new fault location algorithm developed by the direct three-phase circuit analysis for unbalanced distribution systems, which has not been investigated due to high complexity. The proposed algorithm overcomes the limit of the conventional algorithm, which requires the balanced system. It is applicable to any power system, but especially useful for the unbalanced distribution systems. Its effectiveness has been proved through many EMTP simulations
  147.   Ha, H.X., Zhang, B.H., Lv, Z.L., 2003. A novel principle of single-ended fault location technique for EHV transmission lines. Ieee Transactions on Power Delivery 18, 1147-1151.
Abstract: A new fault location principle using one terminal voltage and current data for EHV transmission lines is described in this paper, which is based on distributed parameter line model, breaking through the traditional single-ended fault location ideas. The voltage profile along the healthy line could be calculated using single-ended voltage and current data; however, the voltage profile behind the fault point is not true for a faulted line. Even though, notice the fact that the norm value of derivative function of the "fictitious profile" to distance is minimum at fault point, based on which the fault location function is constructed. The numerical algorithm is also described; this principle is proved by EMTP simulations to be immune to fault resistance, fault types, and fault inception angle. Theoretically, the accuracy of the principle is proportional to the sampling rate of the locator
  148.   Kawady, T., Stenzel, J., 2003. A practical fault location approach for double circuit transmission lines using single end data. Ieee Transactions on Power Delivery 18, 1166-1173.
Abstract: Double circuit transmission lines are frequently subjected to a variety of technical problems from the perspective of protection engineering. These problems are mainly due to the mutual coupling effects between adjacent circuits of the line. In this paper, a new fault location approach for double circuit transmission lines is introduced. It depends only on the data extracted from one end of the line. This practically facilitates implementing and developing this approach, as it needs no information from the other end. The approach is based on modifying the apparent impedance method using modal transformation. Depending on modal transformation, the coupled equations of the transmission line are converted into decoupled ones. This greatly eliminates the mutual effects resulting in an accurate estimation for the fault distance in a straightforward manner. Also the effects of prefault currents, charging currents, and the unknown fault resistance on the estimation accuracy are compensated. The proposed approach was tested via digital simulation using ATP-EMTP in conjunction with MATLAB. Applied test results corroborate the superior performance of the proposed approach
  149.   Popovi, L.M., 2003. A digital fault-location algorithm taking into account the imaginary part of the grounding impedance at the fault place. Ieee Transactions on Power Delivery 18, 1489-1496.
Abstract: The paper presents a new digital fault location algorithm developed for the determination of the location of the transmission line faults. The calculations for the estimation of the fault location are performed using one-terminal voltage and current data of the transmission line. The development of the algorithm is based on the detailed consideration of all the return paths (ground wire, towers, and substation grounding electrodes) of the ground fault current to its sources (the power system). The algorithm takes into account all of the factors important for the accuracy of the estimation (i.e., fault impedance, fault current component supplied from the opposite end of the line, and the prefault current). Also, the imaginary part of the fault impedance is not ignored as is the case with the previously published methods. The proposed algorithm was tested using simulated current data. Sample test results are also included
  150.   Martin, F., Aguado, J.A., 2003. Wavelet-based ANN approach for transmission line protection. Ieee Transactions on Power Delivery 18, 1572-1574.
Abstract: A new approach of digital relays for transmission line protection is presented. The proposed technique consists of a preprocessing module based on discrete wavelet transforms (DWTs) in combination with an artificial neural network (ANN) for detecting and classifying fault events. The DWT acts as an extractor of distinctive features in the input signals at the relay location. This information is then fed into an ANN for classifying fault conditions. A DWT with quasioptimal performance for the preprocessing stage is also presented
  151.   Yonemoto, A., Hisakado, T., Okumura, K., 2003. Expression of transient phenomena at faults on ideal transmission lines by Laguerre functions. Iee Proceedings-Circuits Devices and Systems 150, 141-147.
Abstract: The paper presents analytical expressions for transient waveforms at faults on ideal transmission lines, and shows that impulse-like waveforms which intermittently appear in the transient waveforms are Laguerre functions, which are well known orthogonal functions. The transient waveforms for multi-phase transmission lines are also investigated, and it is shown that the expressions for them are also given by Laguerre functions. In addition, a new method of fault location by a correlation filter bank is demonstrated which uses the orthogonality of Laguerre functions
  152.   Chen, C.S., Liu, C.W., 2003. Fast and accurate fault detection/location algorithms for double-circuit/three-terminal lines using phasor measurement units. Journal of the Chinese Institute of Engineers 26, 289-299.
Abstract: This paper presents new PMU-based fault detection/location algorithms for double-circuit/three-terminal transmission lines. The development of the algorithms is based on distributed transmission line models and synchronized positive sequence voltage and current phasors. The proposed fault detector is very sensitive, such that it can quickly identify faults. In particular, high impedance faults can be easily detected. A fault direction discriminator is also developed to distinguish between internal and external faults with respect to the protected zone. When an internal fault occurs, the discriminator starts the process of fault locating. The methods do not require fault type identification and their computational costs are very low since they do not require iterative operations. Moreover, the algorithms provide excellent performance for transposed and untransposed lines. The EMTP/ATP simulator was used to verify the performance of the methods. The simulation studies show that the algorithms can detect faults quickly, discriminate fault direction correctly, and provide a high degree of accuracy in fault location. The algorithms are independent of various fault and system conditions such as fault types, fault positions, fault path resistance, pre-fault load flows, mutual coupling effect of lines, and line shunt capacitance
  153.   Fernandez, A.L.O., Ghonaim, N.K.I., 2002. A novel approach using a FIRANN for fault detection and direction estimation for high-voltage transmission lines. Ieee Transactions on Power Delivery 17, 894-900.
Abstract: This paper presents a novel approach to fault detection, faulted phase selection, and direction estimation based on artificial neural networks (ANNs). The suggested approach uses the finite impulse response artificial neural network (FIRANN) with the same structure and parameters in each relaying location. Our main objective in this work is to find a fast relay design with a detection time not dependent on fault conditions (i.e., current transformer saturation, dynamic arcing faults, short-circuit level, and system topology) and that uses only unfiltered voltage and current samples at 2 kHz. The suggested relay, which we have named FIRANN-DSDST, is composed of a FIRANN together with post-processing elements. The FIRANN is trained globally using training patterns from more than one relaying position in order to be as general as possible. The FIRANN is trained using an improved training algorithm, which depends on a new synaptic weights updating method, which we have named the mixed updating technique. The proposed relay is trained using training patterns created by simulating a real 400-kV network from the Spanish transmission network (R.E.E.). Finally, the proposed relay is tested using simulated and real fault data. The results encourage the use of this technology in a protective relaying field
  154.   Kim, C.H., Kim, H., Ko, Y.H., Byun, S.H., Aggarwal, R.K., Johns, A.T., 2002. A novel fault-detection technique of high-impedance arcing faults in transmission lines using the wavelet transform. Ieee Transactions on Power Delivery 17, 921-929.
Abstract: This paper describes a novel fault-detection technique of high-impedance faults (HITS) in high-voltage transmission lines using the wavelet transform. Recently, the wavelet transform (WT) has been successfully applied in many fields. The technique is based on using the absolute sum value of coefficients in multiresolution signal decomposition (MSD) based on the discrete wavelet transform (DWT). A fault indicator and fault criteria are then used to detect the HIT in the transmission line. In order to discriminate between HIF and nonfault transient phenomena, such as capacitor and line switching and are furnace loads, the concept of duration time (i.e., the transient time period), is presented. On the basis of extensive investigations, optimal mother wavelets for the detection of HIF are chosen. It is shown that the technique developed is robust to fault type, fault inception, angle, fault resistance, and fault location. The paper demonstrates a new concept and methodology in HIF in transmission lines. The performance of the proposed technique is tested under a variety of fault conditions on a typical 154-kV Korean transmission-line system
  155.   Jiang, J.A., Liu, C.W., Chen, C.S., 2002. A novel adaptive PMU-based transmission-line relay - Design and EMTP simulation results. Ieee Transactions on Power Delivery 17, 930-937.
Abstract: This paper proposes a novel adaptive relaying scheme based on phasor-measurement units (PMUs) for transmission lines. The proposed adaptive relaying scheme can provide an extremely accurate discrimination between in-zone and out-of-zone faults. Two novel and composite fault discrimination indices in terms of Clarke components of synchronized voltage and current phasors at two ends of a line are derived. A line parameter estimation algorithm is developed and built in the newly designed relay to solve the uncertainty problem of line parameters. The proposed relaying scheme is independent of fault types, fault locations, fault path resistance, fault inception angles,, and the variations of source impedance. The tripping decision time of the designed relay is very fast and almost held well within 6 ms for most fault events. All of the EMTP simulation results show-that the proposed adaptive relaying scheme provides a high level of dependability and security
  156.   Sanaye-Pasand, M., 2003. Discussion of "A new protection scheme for fault detection, direction discrimination, classification, and location in transmission lines". Ieee Transactions on Power Delivery 18, 652-653.
  157.   Jiang, J.A., Chen, C.S., Liu, C.W., 2003. Closure on "A new protection scheme for fault detection, direction discrimination, classification, and location in transmission lines". Ieee Transactions on Power Delivery 18, 653-655.
  158.   Dash, P.K., Pradhan, A.K., Panda, G., 2003. Application of artificial intelligence techniques for classification and location of faults on thyristor-controlled series-compensated line. Electric Power Components and Systems 31, 241-260.
Abstract: Radial basis function neural networks (RBFNN) and fuzzy neural networks (FNN) are finding increasing attention as AI techniques. Power systems protection is a complex task in which AI techniques are successfully employed. Minimal RBFNN (MRBFNN) is a newer version of neural network that provides a minimum number of neurons using the sequential learning and pruning strategy. On the other hand, the fuzzy neural network, using a pruning strategy, yields fewer fuzzy rules. These new techniques are employed for the Protection of a power network having a thyristor-controlled series capacitor (TCSC) which introduces further complexity into the protection problem. A comparison of the two new schemes is also outlined
  159.   Ahmed, S.S., Sarker, N.C., Khairuddin, A.B., Ghani, M.R.B.A., Ahmad, H., 2003. A scheme for controlled islanding to prevent, subsequent blackout. Ieee Transactions on Power Systems 18, 136-143.
Abstract: The power systems operated by the utilities in developing countries suffer from a large gap between demand and generation, inadequate transmission capacity, and nonuniform location of the load centers and generating stations. Occurrences of faults in such systems, in most of the cases, end up with the worst consequences (i.e., complete blackout). This paper illustrates the way a blackout can be prevented in real time through controlled segregation of a system into a number of viable islands together with generation and/or load shedding. The nature and location of any fault that warrants such islanding can be ascertained in real time through monitoring the active-power (megawatt) flows at both ends of a number of prespecified lines. The blackout of June 20, 1998 in the Bangladesh Power Development Board system has been used as an example in the illustration. The philosophy of the proposed islanding scheme may be considered for implementation in other power systems also
  160.   Jiang, J.A., Chen, C.S., Liu, C.W., 2003. A new protection scheme for fault detection, direction discrimination, classification, and location in transmission lines. Ieee Transactions on Power Delivery 18, 34-42.
Abstract: This paper presents a new adaptive fault protection scheme for transmission lines using synchronized phasor measurements. The work includes fault detection, direction discrimination, classification, and location. Both fault-detection and fault-location indices are derived by using two-terminal synchronized measurements incorporated with distributed line model and modal transformation theory. The fault-detection index is composed of two complex phasors and the angle difference between the two phasors determines whether the fault is internal or external to the protected zone. The fault types can be classified by the modal fault-detection index. The proposed scheme also combines online parameter estimation to ensure protection scheme performance and achieve adaptive protection. Extensive simulation studies show that the proposed scheme provides a fast relay response and high accuracy in fault location under various system and fault conditions. The proposed method responds very well with regards to dependability, security, and sensitivity,(high-resistance fault coverage)
  161.   Zhang, D.J., Wu, Q.H., Zhang, J.F., Nuttall, K.I., 2002. Accurate fault location based on transients extraction using mathematical morphology. Electronics Letters 38, 1583-1585.
Abstract: A multi-resolution morphological gradient method is developed to efficiently extract fault-generated transients and accurately identify fault locations in a power transmission line system
  162.   Coury, D.V., Oleskovicz, M., Aggarwal, R.K., 2002. An ANN routine for fault detection, classification, and location in transmission lines. Electric Power Components and Systems 30, 1137-1149.
Abstract: This article presents an Artificial Neural Network (ANN) approach to simulate a complete scheme for distance protection of transmission lines. The protection technique is based on a modular approach whereby different neural network modules have been adopted for fault detection, fault classification and fault location. Three-phase voltage and current samples were utilized as inputs for the proposed scheme. The Alternative Transients Program (ATP) software was used to generate data for the transmission line (400 W). The results obtained show that the global performance of the ANN architectures is highly satisfactory under a wide variety of different fault conditions
  163.   Chanda, D., Kishore, N.K., Sinha, A.K., 2003. A wavelet multiresolution analysis for location of faults on transmission lines. International Journal of Electrical Power & Energy Systems 25,  59-69.
Abstract: Faults on EHV lines are quite common. They cause disruption in power supply. Accurate location of faults will result in faster maintenance and restoration of supply. This paper presents a new method for the location of faults based on wavelet multiresolution analysis (MRA). EMTP (Microtran) is employed to generate the time domain input signal. Daubechies eight (D-8) wavelet transforms of the threes phase currents on transmission lines from both the ends are used. The effects of fault inception angle and fault impedance are examined. Extensive simulation work has been carried out and results indicate that the proposed method is very effective in locating the fault with a high accuracy. (C) 2002 Elsevier Science Ltd. All rights reserved
  164.   Hisakado, T., Tanaka, K., Okumura, K., 2002. A transmission line fault-location system using the wavelet transform. Electrical Engineering in Japan 140, 27-37.
Abstract: This paper describes the locating system of line-to-ground faults on a transmission line by wavelet transform. The possibility of the location with the surge generated by a fault has been theoretically proposed. In order to make the method practicable, we realize very fast processors. We design wavelet transform and location chips, and construct a very fast fault location system by processing the measured data in parallel. This system is realized by a computer with three FPGA processor boards on a PCI bus. The processors are controlled by UNIX and the system has the graphic user interface with X window system. (C) 2002 Wiley Periodicals, Inc
  165.   Soliman, S.A., Abdel-Rahman, M.H., Al-Attar, E., El-Hawary, M.E., 2002. An algorithm for estimating fault location in an unbalanced three-phase power system. International Journal of Electrical Power & Energy Systems 24, 515-520.
Abstract: A new algorithm for estimating fault location on a transmission line, as well as the fault type, is studied and tested using simulation data obtained from the Electromagnetic Transient Program (EMTP). The proposed algorithm is based on the least absolute value estimation approach (LAV), and uses digitized samples of post-fault voltage and current waveforms at the relay locations. The proposed algorithm is applied to two different models of the transmission line. The first model is a three phase long transmission line, while the second model is a three phase three terminals transmission line. The measurements taken at the relay location do not need to be synchronized. Effects of critical parameters on the behavior of the proposed algorithm and on the estimated fault location are examined. A computational comparison between the proposed algorithm and the least errors square (LES) is presented in the paper, (C) 2002 Elsevier Science Ltd. All rights reserved
  166.   Kamwa, I., Grondin, R., 2002. PMU configuration for system dynamic performance measurement in large multiarea power systems. Ieee Transactions on Power Systems 17, 385-394.
Abstract: Effective assessment of the dynamic performance of the power system requires wide-area information from properly distributed phasor measurement units (PMUs). However, to maximize the information content of the captured signals, the sensors need to be located appropriately, with due account given to the structural properties underlying the given system. In this paper, two numerical algorithms are proposed to achieve this goal. They aim to maximize the overall sensor response while minimizing-the correlation among sensor outputs so as to minimize the redundant information provided by multiple sensors. The sensor responses of interest are the bus voltage magnitude, and the angle and frequency coherency indexes, which are estimated by means of a statistical sampling of power system response signals from a transient-stability program. Through the "successive addition" scheme, one of these algorithms easily incorporates mandatory locations such as tie-line busses and large generator step-up transformers. The proposed approaches are first illustrated on the Hydro-Quebec transmission grid and then on a 9-area/67-bus/23-machine test network designed with well-defined geographical boundaries and pre-specified weak interties between electrically coherent areas
  167.   Lobos, T., Rezmer, J., 2002. Wavelet transforms for real-time estimation of transmission line impedance under transient conditions. Electrical Engineering 84, 63-70.
Abstract: Waveforms of voltages and currents in electrical power systems may include higher harmonics, transient components and random noise. For control and protection devices, it is necessary to estimate parameters of the basic waveform. The most well-known methods are based on the Fourier technique. The estimated phasors of the basic component can be applied to the calculation of the impedance of a faulty transmission line. In this paper, the current and voltage phasors were estimated using complex wavelets. The filter properties of the wavelet approach are better than those of the Fourier
  168.   Ding, Y., Ceglarek, D., Shi, J.J., 2002. Fault diagnosis of multistage manufacturing processes by using state space approach. Journal of Manufacturing Science and Engineering-Transactions of the Asme 124, 313-322.
Abstract: This paper presents a methodology for diagnostics of fixture failures in multistage manufacturing processes (MMP). The diagnostic methodology is based oil the stale-space model of the MMP process, which includes part fixturing layout geometry and sensor location. The state space model of the MMP characterizes the propagation of fixture fault variation along the production stream, and is used to generate a set of predetermined fault variation patterns. Fixture faults are then isolated by using mapping procedure that combines the Principal Component Analysis (PCA) with pattern recognition approach. The fault diagnosability conditions for three levels: (a) within single station, (b) between stations, and (c)for the overall process, are developed. The presented analysis integrates the state space model of the process and matrix perturbation theory to estimate the upper bound for isolationability of fault pattern vectors caused b), correlated and uncorrelated noises. A case study illustrates the proposed method
  169.   Chen, C.S., Liu, C.W., Jiang, J.A., 2002. A new adaptive PMU based protection scheme for transposed/untransposed parallel transmission lines. Ieee Transactions on Power Delivery 17, 395-404.
Abstract: This paper proposes a brand-new adaptive phasor measurement unit (PMU) based protection scheme for both transposed and untransposed parallel transmission lines. The development of the scheme is based on the distributed line model and the synchronized phasor measurements at both ends of lines. By means of eigenvalue/eigenvector theory to decouple the mutual coupling effects between parallel lines, the fault detection and location indices are derived. The two proposed indices are used in coordination such that the internal and external fault events can be distinguished completely. By on-line estimating the line parameters under the actual power system conditions, the proposed scheme will respond more accurately to power system faults. Extensive simulation results using EMTP have verified that the accuracy of the fault location achieved is up to 99.9%. The proposed protection system responds well and fast with regard to dependability and security. All the results show that the performance of the proposed detection/location indices is independent of fault types, locations, resistance, source impedance, fault inception angles, and load flows
  170.   Lin, Y.H., Liu, C.W., Yu, C.S., 2002. A new fault locator for three-terminal transmission lines - Using two-terminal synchronized voltage and current phasors. Ieee Transactions on Power Delivery 17, 452-459.
Abstract: With the advent of the high synchronization accuracy of modern phasor measurement units (PMUs), a new approach for accurately locating faults on three-terminal lines is proposed. Using the data measured from two terminals of three-terminal lines, the proposed technique can provide an extremely accurate fault location. An EMTP/ATP simulator is used to demonstrate the performance of the proposed fault locator. The simulation results show that the accuracy of fault location is very high under various fault resistance, fault locations, prefault loading conditions, source impedance and fault types
  171.   Chen, S.M., Du, Y., Fan, L.M., He, H.M., Zhong, D.Z., 2002. Evaluation of the Guang Dong lightning location system with transmission line fault data. Iee Proceedings-Science Measurement and Technology 149, 9-16.
Abstract: The Guang Dong lightning location system (GDLLS) was put into operation in 1997. Its performance, including detection efficiency and location accuracy, was evaluated with the data of the recorded lightning faults on 110, 220 and 500 kV transmission lines in 1997-1999. Lightning parameters, such as thunderstorm days, ground-flash density and peak lightning current were estimated with the lightning data collected by GDLLS. It is found that the detection efficiency is as high as 86%, and the median lightning accuracy is about 1.3 kin. The correlation between the number of detected lightning flashes and recorded transmission fine faults is weak, but can be improved if more appropriate analysis methods or data are employed
  172.   Osowski, S., Salat, R., 2002. Fault location in transmission line using hybrid neural network. Compel-the International Journal for Computation and Mathematics in Electrical and Electronic Engineering 21, 18-30.
Abstract: The paper presents the application of self-organizing neural network for the location of the fault in the transmission line and estimation of the Parameter of the faulty element. The location of fault is done on the basis of the measurement of some node voltages of the line and appropriate Preprocessing it to enhance the differences between different faults. The hybrid neural network is used to solve the problem. The self-organizing layer of this network is used as the classifier. The output postprocessing MLP structure realizes the association of the place of the fault and its parameter with the measured set of node voltages. The results of computer experiments are given in the paper and discussed
  173.   Lim, Y.S., Strbac, G., 2002. Analytical approach to probabilistic prediction of voltage sags on transmission networks. Iee Proceedings-Generation Transmission and Distribution 149, 7-14.
Abstract: Quantification of voltage sags at a location of interest is the basic requirement for assessing the compatibility between equipment and electrical supply. An analytical method is described that has been developed to determine the probability density functions of voltage sags caused by three phase faults across the network. The method takes into account the impact of fault positions along transmission circuits and patterns of generation associated with the corresponding load demands on the voltage sag profiles. The developed algorithm is applied to the IEEE 24-bus reliability test system to verify the technique and illustrate its application
  174.   Yu, C.S., Liu, C.W., Yu, S.L., Jiang, J.A., 2002. A new PMU-based fault location algorithm for series compensated lines. Ieee Transactions on Power Delivery 17, 33-46.
Abstract: This paper presents a new fault location algorithm based on phasor measurement units (PMUs) for series compensated lines. Traditionally, the voltage drop of series device is computed by the device model in the fault locator of series compensated lines, but using this approach errors are induced by the inaccuracy of the series device model or the uncertainty operation mode of the series device. The proposed algorithm does not utilize the series device model and knowledge of the operation mode of the series device to compute the voltage drop during the fault period. Instead, the proposed algorithm uses two-step algorithm prelocation step and correction step, to calculate the voltage drop and fault location. The proposed technique can be easily applied to any series FACTS compensated line. EMTP generated data using a 30-km 34-kV transmission line has been used to test the accuracy of the proposed algorithm. The tested cases include various fault types, fault locations, fault resistances, fault inception angles, etc. The study also considers the effect of various operation modes of the compensated device during the fault period. Simulation results indicate that the proposed algorithm can achieve up to 99.95% accuracy for most tested cases
  175.   Pradhan, A.K., Dash, P.K., Panda, G., 2001. A fast and accurate distance relaying scheme using an efficient radial basis function neural network. Electric Power Systems Research 60, 1-8.
Abstract: The paper presents a new approach for classification and location of faults on a transmission line using a newer version of radial basis function neural network (RBFNN) which provides a more efficient approach for training and computation. The input data to the RBFNN comprise the normalised peak values of the fundamental power system voltage and current waveforms at the relaying location obtained during fault conditions. The extraction of the peak components is carried out using an extended Kalman filter (EKF) suitably modelled to include decaying d.c., third and fifth harmonics along with the fundamental. The fault training patterns required using the efficient version of RBF neural network are much less in comparison to the conventional RBF network and the choice of neurons and the parameters of the network are systematically arrived without resorting to trial and error calculations. The new approach provides a robust classification of different fault types for a variety of power system operating conditions with resistance in the fault path. Further a new fault location strategy is formulated using four neural networks, one each for the major category of faults like LG, LL, LLG and LLL faults. The proper feature selection for the networks results in an accurate and fast distance relaying scheme. (C) 2001 Published by Elsevier Science B.V
  176.   Adu, T., 2001. A new transmission line fault locating system. Ieee Transactions on Power Delivery 16, 498-503.
Abstract: The paper describes a new fault locating system that has been developed at Mehta Tech, Inc (MTI). The distance calculating technique of the system is based on the reactance method of fault distance estimation, using data from one terminal of a transmission line. The technique compensates for errors caused by factors such as load flow and fault resistance. The system has been in commercial use by some reputable electric utilities, both local and international for over three years. The paper also presents some field results that have been obtained from some of these electric utilities that are using the new fault locating system
  177.   Purushothama, G.K., Narendranath, A.U., Thukaram, D., Parthasarathy, K., 2001. ANN applications in fault locators. International Journal of Electrical Power & Energy Systems 23, 491-506.
Abstract: Recent developments indicate that Artificial Neural Networks (ANNs) may be appropriate for assisting dispatchers in operating electric power systems. The fault location algorithm being a key element in the digital relay for power transmission line protection, this paper discusses the potential applicability of ANN techniques for determination of fault location and fault resistance on EHV transmission lines with remote end in-feed. Most of the applications make use of the conventional Multi Layer Perceptron (MLP) model based on back propagation algorithm. However, this model suffers from the problem of slow learning rate. A modified ANN learning technique for fault location and fault resistance determination is presented in this paper. A reasonably small NN is built automatically without guessing the size, depth, and connectivity pattern of the MY in advance. Results of study on a 400 kV transmission Line are presented for illustration purposes. Performance of the modified ANN is compared with the analytical algorithms and conventional MLP algorithm for different combinations of pre-fault loading condition, fault resistance and fault location. The results are found to be encouraging. (C) 2001 Elsevier Science Ltd. All rights reserved
  178.   Nagata, M., Tanaka, K., Taniguchi, H., 2001. FCL location selection in large scale power system. Ieee Transactions on Applied Superconductivity 11, 2489-2494.
Abstract: Maximum short circuit current of modern power system is becoming so large that the current should be reduced to make more efficient use of power system transmission capability, Fault Current Limiter (FCL) is a promising solution of this problem and it can be categorized into two types: constant impedance type. FCL and current limiting type FCL. Current limiting type FCL such as rectifier typo super-conducting FCL (RSFCL) has variable equivalent impedance depending on the limit of the current through FCL and power system impedances. In this paper, a method is proposed to incorporate RSFCL into short circuit current analysis, which is needed to evaluate the effectiveness of FCL installed In a large scale power system, Also, an efficient method to find FCL locations suitable for reduction of short circuit currents of more than one fault locations is developed, The efficiency and effectiveness of these methods are shown by numerical examples
  179.   Funabashi, T., Otoguro, H., Mizuma, Y., Dube, L., Kizilcay, M., Ametani, A., 2001. Influence of fault arc characteristics on the accuracy of digital fault locators. Ieee Transactions on Power Delivery 16, 195-199.
Abstract: This paper has proposed a time domain model of a fault locator with special reference to fault are nonlinearities by applying the MODELS language of the EMTP. It has been found that an impedance relay type locator is significantly influenced by the fault are nonlinearities, while the current diversion ratio method is not influenced, This validates the advantage of the current diversion approach over the impedance approach
  180.   Tawfik, M.M., Morcos, M.M., 2001. ANN-based techniques for estimating fault location on transmission lines using prony method. Ieee Transactions on Power Delivery 16, 219-224.
Abstract: A system is proposed to locate faults on transmission lines using the traveling wave phenomenon, Prony method is used to analyze the voltage or current signal at the local bus and extract its modal information. This information represents the traveling wave generated by the fault and can be used to estimate its location, Artificial Neural Networks (ANNs) are used to estimate the fault location based on the modal information, Two schemes are presented; the first with a voltage input signal and the second with a current input signal. Training and testing data are obtained by ATP-EMTP simulations. Tests were done to study the effect of fault resistance variation and fault incidence angle on both schemes. The system has the advantages of utilizing single-end measurements, using either a voltage or current signal; no pre-fault data is required
  181.   Dash, P.K., Pradhan, A.K., Panda, G., 2001. Application of minimal radial basis function neural network to distance protection. Ieee Transactions on Power Delivery 16, 68-74.
Abstract: The paper presents a new approach for the protection of power transmission lines using a minimal radial basis function neural network (MRBFNN), This type of RBF neural network uses a sequential learning procedure to determine the optimum number of neurons in the hidden layer without resorting to trial and error. The input data to this network comprises fundamental peak values of relaying point voltage and current signals, the zero-sequence component of current and system operating frequency. These input variables are obtained by Kalman filtering approach. Further, the parameters of the network are adjusted using a variant of extended Kalman filter known as locally iterated Kalman filter to produce better accuracy in the output for harmonics, de offset and noise in the input data. The number of training patterns and the training time are drastically reduced and significant accuracy is achieved in different types of fault classification and location in transmission lines using computer simulated tests
  182.   Eissa, M.M., Malik, O.P., 2000. Investigation of impedance based protection technique for EHV 3-terminal double circuit lines. Iee Proceedings-Generation Transmission and Distribution 147, 317-321.
Abstract: A digital impedance based protection scheme for a 3-terminal transmission line has been implemented on a digital signal processor board and tested on a physical model of a double-circuit 3-terminal line with a source at each end. One combined relay at each terminal of the double-circuit line, instead of two relays, is proposed. Each relay is fed by three voltage and six current signals. Realtime tests conducted on the physical model for various faults show that high fault resistance at the teed point, current infeed, remote-end infeeds, fault location, source impedance and far-end faults cause no problem in proper relay operation. Also, 100% of the lines are protected
  183.   Mazon, A.J., Zamora, I., Minambres, J.F., Zorrozua, M.A., Barandiaran, J.J., Sagastabeitia, K., 2000. A new approach to fault location in two-terminal transmission lines using artificial neural networks. Electric Power Systems Research 56, 261-266.
Abstract: This paper presents a new approach to fault location in two-terminal overhead transmission lines, using artificial neural networks (ANN's). The method presented enables the distance to be determined at which the fault occurs in a two-terminal transmission line using the fundamental components of 50/60 Hz of the fault and pre-fault voltage and current magnitudes, measured in each phase of the reference end. The main characteristic of the method is the consideration during the training period of both correctly measured magnitudes and magnitudes affected by errors. Using properly validated fault simulation software has checked the accuracy of the method with both correct initial data and initial data containing errors. (C) 2000 Elsevier Science S.A. All rights reserved
  184.   Jiang, J.A., Lin, Y.H., Yang, J.Z., Too, T.M., Liu, C.W., 2000. An adaptive PMU based fault detection/location technique for transmission lines - Part II: PMU implementation and performance evaluation. Ieee Transactions on Power Delivery 15, 1136-1146.
Abstract: Part I of this paper set sets forth theory and algorithms for adaptive fault detection/location technique,which is based on Phasor Measurement Unit (PMU). This paper is Part II of this paper set. A new timing device named "Global Synchronism Clock Generator, GSCG'' including its hardware and software design is described in this paper, Experimental results show that the synchronized error of rising edge between the two GSCGs clock is well within 1 ps when the clock frequency is below 2.499 MHz. The measurement results between Chung-Jeng and Chang-Te 161 kV substations of Taiwan Power company by PMU equipped with GSCG is presented and the accuracy for estimating parameters of line is verified. The new developed DFT based method (termed as Smart Discrete Fourier Transform, SDFT) and line parameter estimation algorithm are combined with PR-IU configuration to form the adaptive fault detector/locator system. Simulation results hare shown that SDFT method can extract exact phasors in the presence of frequency deviation and harmonics. The parameter estimation algorithm can also trace exact parameters very well, The SDFT method and parameter estimation algorithm can achieve accuracies of up to 99.999% and 99.99%, respectively, The EMTP is used to simulate a 345 kV transmission line of Taipower System. Results have shown that the proposed technique yields correct results independent of fault types and is insensitive to the variation of source impedance, fault impedance, and line loading. The accuracy of fault location estimation achieved can be up to 99.9% for many simulated cases, The proposed technique will be very suitable for implementation in an integrated digital protection and control system for transmission substations
  185.   Bo, Z.Q.Q., Weller, G., Lomas, T., Redfern, M.A., 2000. Positional protection of transmission systems using Global Positioning System. Ieee Transactions on Power Delivery 15, 1163-1168.
Abstract: This paper presents a new technique for the protection of power transmission systems by using the Global Positioning System (GPS) and fault generated transients. In the scheme, the relay contains a fault transient detection system together with a communication unit, which is connected to the power line through the high voltage coupling capacitors of the CVT. Relays are installed at each busbar in a transmission network, These detect the fault generated high frequency voltage transient signals and record the time instant corresponding to when the initial travelling wave generated by the fault arrives at that busbar, The communication unit is used to transmit and receive coded digital signals of the Local information to and from the associated relay(s) in the system. At each substation, the relays determine the location of the fault by comparing the GPS time stamps measured Locally with those received from the adjacent substations. Extensive simulation studies presented in the paper demonstrate the feasibility of the scheme
  186.   Gopalakrishnan, A., Kezunovic, M., McKenna, S.M., Hamai, D.M., 2000. Fault location using the distributed parameter transmission line model. Ieee Transactions on Power Delivery 15, 1169-1174.
Abstract: Earlier work at Texas A&M University led to the development of transmission line fault location algorithms that were based on synchronized sampling of the voltage and current data from the two ends of the line. The Line models used in the algorithms were based on lumped parameter models for electrically short lines, or lossless distributed parameter models for electrically long lines, In this paper, the lossless line model is modified to account for the series losses in the line. The line model equations are then solved in the time domain to accurately locate the fault, Testing of the modified algorithm is performed on a power system belonging to the Western Area Power Administration. Extensive EMTP based simulations are used to generate data that are supplied as inputs to the fault location algorithm. To make the testing as realistic as possible, detailed models of instrument transformers are used in the simulation of the various fault cases
  187.   Sadeh, J., Ranjbar, A.M., Hadjsaid, N., Feuillet, R., 2000. Accurate fault location algorithm for power transmission lines. European Transactions on Electrical Power 10, 313-318.
Abstract: In this paper we propose a new fault location algorithm for power transmission lines based on one terminal voltage and current data. A distributed time domain model of the line is used as a basis for algorithm development. The suggested technique only rakes advantage of post-fault voltage and current samples taken at one end of the line and does not require filtering of DC offset and high-frequency components of the recorded signals, which are present during transient conditions. Another advantage of the proposed method is the application of a very narrow window of data i.e. less than 1/4 of a cycle. The paper also proposes two different algorithms for lossless and lossy line models. Computer simulations approved the accuracy of the proposed methods
  188.   Dash, P.K., Pradhan, A.K., Panda, G., 2000. Adaptive distance learning protection using a fuzzy neural network. Engineering Intelligent Systems for Electrical Engineering and Communications 8, 169-175.
Abstract: A new approach to distance relaying using fuzzy neural network (FNN) is presented. The FNN can be viewed either as a fuzzy logic system (FLS), a neural network (NN) or fuzzy neural network. The structure is seen as a neural network for training and a fuzzy viewpoint is utilized to gain insight the system and to simplify the model. The number of rules is determined by the data itself and therefore smaller number of rules is produced. The network is trained with back propagation algorithm, A pruning strategy is applied to eliminate the redundant rules and fuzzification neurons, consequently a compact structure is achieved. The classification and location tasks are accomplished by using different FNNs. Once the fault type is identified by the FNN-classifier the selected FNN-locater estimates the location of the fault accurately. The networks make use of fundamental currents and voltages at the relay end along with sequence component of current. The superior capability of the strategy is adjudged through test results for different situations of power system including high resistance in the fault path
  189.   Dash, P.K., Pradhan, A.K., Panda, G., 2000. A novel fuzzy neural network based distance relaying scheme. Ieee Transactions on Power Delivery 15, 902-907.
Abstract: This paper presents a nem approach to distance relaying using fuzzy neural network (FNN). The FNN can be viewed either as a fuzzy system, a neural network or fuzzy neural network. The structure is seen as a neural network for training and a fuzzy viewpoint is utilized to gain insight into the system and to simplify the model. The number of rules is determined by the data itself and therefore smaller number of rules is produced. The network is trained with back propagation algorithm. A pruning strategy is applied to eliminate the redundant rules and fuzzification neurons. consequently a compact structure is achieved. The classification and location tasks are accomplished by using different FNN's, Once the fault type is identified by the FNN classifier the selected fault locating FNN estimates the location of the fault accurately, Normalized peaks of fundamental voltage and current waveforms are considered as inputs to all the networks and an additional input derived from df component is fed to fault locating networks. The peaks and de component are extracted from sampled signals by the EKF, Test results show that the nem approach provides robust and accurate classification/location of faults for a variety of power system operating conditions even with resistance in the fault path
  190.   Sadeh, J., Hadjsaid, N., Ranjbar, A.M., Feuillet, R., 2000. Accurate fault location algorithm for series compensated transmission lines. Ieee Transactions on Power Delivery 15, 1027-1033.
Abstract: In this paper, an accurate fault location algorithm for series compensated power transmission lines is presented. Distributed time domain model is used for modeling of the transmission lines. The algorithm makes use of two subroutines for estimation of the fault distance-one for faults behind the series capacitors and another one for faults in front of the series capacitors. Then a special procedure to select the correct solution is utilized. Samples of voltages and currents at both ends of the line are taken synchronously and used to calculate the location of the fault. The proposed algorithm is independent of fault resistance and does not require any knowledge of source impedance. The proposed method has been tested using the EMTP/ATP model of a 400 kV 300 km transmission line, which is compensated, by a three-phase capacitor bank in the middle. The results of computer simulation confirm the accuracy of the proposed method
  191.   Jiang, J.A., Yang, J.Z., Lin, Y.H., Liu, C.W., Ma, J.C., 2000. An adaptive PMU based fault detection/location technique for transmission lines part I: Theory and algorithms. Ieee Transactions on Power Delivery 15, 486-493.
Abstract: An adaptive fault detection/location technique based on Phasor Measurement Unit (PMU) for an EHV/UHV transmission line is presented in this two paper set. This paper is Part I of this set. A fault detection/location index in terms of Clarke components of the synchronized voltage and current phasors is derived. The line parameter estimation algorithm is also developed to solve the uncertainty of parameters caused by aging of transmission lines. This paper also proposes a new Discrete Fourier Transform (DFT) based algorithm (termed as Smart Discrete Fourier Transform, SDFT) to eliminate system noise and measurement errors such that extremely accurate fundamental frequency components can be extracted for calculation of fault detection/location index. The EMTP was used to simulate a high voltage transmission line with faults at various locations, To simulate errors involved in measurements, Gaussian-type noise has been added to the raw output data generated by EMTP. Results have shown that the new DPT based method can extract exact phasors in the presence of frequency deviation and harmonics. The parameter estimation algorithm can also trace exact parameters very well. The accuracy of both new DFT based method and parameter estimation algorithm can achieve even up to 99.999 % and 99.99 % respectively, and will be presented in Part II, The accuracy of fault location estimation by the proposed technique can achieve even up to 99.9 % in the performance evaluation, which is also presented in Part II
  192.   Zhang, Y., Zhang, Q.C., Song, W.N., Yu, Y.X., Li, X., 2000. Transmission line fault location for double phase-to-earth fault on non-direct-ground neutral system. Ieee Transactions on Power Delivery 15, 520-524.
Abstract: An accurate algorithm for locating double phase-to-earth fault on transmission line of nondirect ground neutral system is presented. The algorithm employs the faulted phase network and zero-sequence network as the fault location model. It effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The technique embodies an accurate location by measuring only one local end data. The algorithm is used in a procedure that provides the automatic determination of faulted line and phase, rather than requires engineer to specify them. Simulation results have shown the effectiveness of the algorithm under the condition of earth faults
  193.   Funabashi, T., Otoguro, H., Mizuma, Y., Dube, L., Ametani, A., 2000. Digital fault location for parallel double-circuit multi-terminal transmission lines. Ieee Transactions on Power Delivery 15, 531-537.
Abstract: Two new methods are proposed for fault point location in parallel double-circuit multi-terminal transmission lines by using voltages and currents information from CCVT's and CT's at all terminal. These algorithms take advantage of the fact that the sum of currents flowing into a fault section equals the sum of the currents at all terminals. Algorithm-1 employs an impedance calculation and Algorithm-2 employs the current diversion ratio method, Computer simulations are carried out and applications of the proposed methods are discussed. Both algorithms can be applied to all types of fault such as phase-to-ground and phase-to-phase faults, As one equation can be used for all types of fault, classification of fault types and selection of faulted phase are not required. Phase components of the line impedance are used directly, so compensation of unbalanced line impedance is not required
  194.   Abur, A., Magnago, F.H., 2000. Use of time delays between modal components in wavelet based fault location. International Journal of Electrical Power & Energy Systems 22, 397-403.
Abstract: This paper presents an improved fault location method based on the traveling wave theory of the transmission lines. Fault transients recorded at one end of a transmission line are processed to determine the distance from the fault location. Wavelet transform is utilized for this purpose. The proposed method also takes advantage of the different travel times of the modal components in differentiating between dose-in and remote end faults. The approach has the advantages of being independent of the fault impedance, mutual coupling effects and series compensation capacitors. The method's performance for typical faults is illustrated using transient simulations obtained by an electromagnetic transients program. (C) 2000 Elsevier Science Ltd. All rights reserved
  195.   Kim, C.H., Lee, M.H., Aggarwal, R.K., Johns, A.T., 2000. Educational use of EMTP MODELS for the study of a distance relaying algorithm for protecting transmission lines. Ieee Transactions on Power Systems 15, 9-15.
Abstract: This paper presents the implementation of a distance relaying algorithm using EMTP MODELS, in which we have simplified the procedures of system modeling and distance relaying system by using a single structure of MODELS. The technique presented is based on integrating the modeling of the power system and the protective system in one program module. The purpose of this paper is to provide systematic relaying concepts by modeling a digital relaying system using MODELS functions within EMTP in a closed-loop manner, principally to facilitate and enhance an understanding of the basic concepts of distance relaying of final year undergraduate students/postgraduate students/young engineers who are new to the subject of power system protective relaying, Various elements of digital distance relaying are organized to generate a systematic approach to modeling the actual hardware of digital relaying systems. Case studies relating to the most commonly encountered single phase-to-ground fault and phase-to-phase fault are presented and various fault distances and fault inception angles are considered
  196.   Chen, Z.H., Maun, J.C., 2000. Artificial neural network approach to single-ended fault locator for transmission lines. Ieee Transactions on Power Systems 15, 370-375.
Abstract: This paper describes the application of an artificial neural network-based algorithm to the single-ended fault location of transmission lines using voltage and current data. From the fault location equations, similar to the conventional approach, this method selects phasors of prefault and superimposed voltages and currents from all phases of the transmission line as inputs of the artificial neural network. The outputs of the neural network are the fault position and the fault resistance. With its function approximation ability, the neural network is trained to map the nonlinear relationship existing in the fault location equations with the distributed parameter line model. It can get both fast speed and high accuracy. The influence of the remote-end infeed on neural network structure is studied. A comparison with the conventional method has been done. It is shown that the neural network-based method can adapt itself to big variations of source impedances at the remote terminal. Finally, when the remote source impedances vary in small ranges, the structure of artificial neural network has been optimized by the pruning method
  197.   Dash, P.K., Pradhan, A.K., Panda, G., Liew, A.C., 2000. Adaptive relay setting for flexible AC transmission systems (FACTS). Ieee Transactions on Power Delivery 15, 38-43.
Abstract: The paper presents an apparent impedance calculation procedure for distance relaying of transmission line involving FACTS devices, particularly the UPFC (unified power flow controller). The presence of UPFC significantly affects the trip boundaries which are also adversely affected by fault resistance combined with remote end infeed, Depending on the UPFC location, the trip boundary is influenced by the fault location, prefault condition, the are fault resistance and the parameters of the UPFC itself (series voltage magnitude and phase angle). The adaptive nature of this protection scheme necessitates the use of a neural network for generation of trip boundaries
  198.   Wilson, R.E., Zevenbergen, G.A., Mah, D.L., Murphy, A.J., 1999. Calculation of transmission line parameters from synchronized measurements. Electric Machines and Power Systems 27, 1269-1278.
Abstract: Accurate knowledge of transmission system parameters, such as series impedance, optimizes distance relay settings and impedance-based fault location. A new method is developed to measure transmission line impedances and admittances from synchronized phasor measurements. Power system voltage and current phasors were recorded during commissioning tests of a 525 kV transmission system containing shunt and series compensation. Steady-state phase angles (delta) and magnitudes of line-side voltages and currents were measured relative to a satellite-based global time standard at two substations. Fairs of synchronized measurements were used to directly calculate real-time steady-state ABCD parameters. For comparison, two-port ABCD transmission system parameters were derived by classical methods and from an ElectroMagnetics Transients Program (EMTP) transmission system design model. To verify the accuracy of the measured parameters, a new method comparing field measured with calculated power flows was developed. Sending-end power flow was measured from accurate recordings and was compared with pourer flow calculated using the three estimates of ABCD parameters, sending-end voltages, and receiving-end voltages. Close agreement was found between field-measured pourer flows and calculations using the measured ABCD parameters
  199.   Aggarwal, R.K., Xuan, Q.Y., Dunn, R.W., Johns, A.T., Bennett, A., 1999. A novel fault classification technique for double-circuit lines based on a combined unsupervised/supervised neural network. Ieee Transactions on Power Delivery 14, 1250-1256.
Abstract: The work described in this paper addresses the problems encountered by conventional techniques in fault type classification in double-circuit transmission lines; these arise principally due to the mutual coupling between the two circuits under fault conditions, and this mutual coupling is highly variable in nature. It is shown that a neural network based on combined unsupervised/supervised training methodology provides the ability to accurately classify the fault type by identifying different patterns of the associated voltages and currents. The technique is compared with that based solely on a supervised training algorithm (ie back-propagation network classifier). It is then tested under different fault types, location, resistance and inception angle; different source capacities and load angles are also considered. All the test results show that the proposed fault classifier is very well suited for classifying fault types in double-circuit lines
  200.   Djuric, M.B., Radojevic, Z.M., Terzija, V.V., 1999. On time domain overhead lines numerical protection. Electric Machines and Power Systems 27, 889-904.
Abstract: A new fault location numerical algorithm based on terminal data and derived in time domain is presented. The fault location and its nature (arcing or arcless fault) are estimated using Least Error Squares Technique. In the paper, the are, occurring on the fault point, is included into the problem consideration. The algorithm is derived for the case of a three-phase symmetrical fault. The results of the algorithm testing through computer simulation and under laboratory conditions are given. The influence of higher-order harmonics is investigated and presented
  201.   Altuve, H.J., Chacon, O.L., Vazquez, E., Posadas, D., Sanchez, E.N., 1999. Neural-network-based fault location estimator for transmission line protection. Journal of Intelligent & Fuzzy Systems 7, 159-171.
Abstract: PL classical task in the protection of transmission lines against short circuits is the estimation of the electrical distance to the fault and its comparison against a given threshold to determine whether the line is faulted or not. This paper presents a novel neural network approach to this problem, as a step towards the design of a neural protective relay. Two different alternatives are proposed and evaluated in the paper, which resemble the amplitude and phase signal comparison principles currently used in analog protective relays. Obtained results confirm that neural network technology can successfully be used to estimate the fault location for transmission line protection
  202.   Saha, M.M., Izykowski, J., Rosolowski, E., Kasztenny, B., 1999. A new accurate fault locating algorithm for series compensated lines. Ieee Transactions on Power Delivery 14, 789-797.
Abstract: This paper presents a new, accurate and robust fault locating algorithm for series compensated lines. The algorithm is developed as a one-end fundamental frequency based technique and offsets both the series compensation effect and the reactance effect resulting from the remote end in-feed. The method uses phase coordinates (abc) instead of symmetrical components (012). The basic algorithm is presented for a line compensated by one three-phase bank or series capacitors. The presented fault locating method has been extensively tested using the EMTP model of a 400kV 300km transmission line. The enclosed results demonstrate very high accuracy and robustness of the algorithm
  203.   Zhang, Q.C., Zhang, Y., Song, W.N., Yu, Y.X., Wang, Z.G., 1999. Fault location of two-parallel transmission line for non-earth fault using one-terminal data. Ieee Transactions on Power Delivery 14, 863-867.
Abstract: An accurate fault-location algorithm for two-parallel transmission line of direct ground neutral system is presented. The algorithm employs the faulted circuit and healthy circuit of two-parallel line as fault-location model, in which remote source impedance is not involved. It effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. It embodies an accurate location by measuring only one local end data and it is used in a procedure that provides the automatic determination of fault types and phases, rather than requires engineer to specify them. Simulation results have shown the effectiveness of the algorithm under the conditions of non-earth fault (phase-to-phase fault and three-phase fault with and without earth-connection)
  204.   Zhang, Q., Zhang, Y., Song, W., Yu, Y., 1999. Transmission line fault location for phase-to-earth fault using one-terminal data. Iee Proceedings-Generation Transmission and Distribution 146, 121-124.
Abstract: An accurate algorithm for fault location of a single phase-to-earth fault on a two-parallel transmission line is presented. The faulted phase circuit and the zero-sequence circuit of the two-parallel line are used as a fault location model, in which the source impedance of the remote end is not involved. The algorithm effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. It embodies an accurate fault location by measuring only local data and is used in a procedure that provides the automatic determination of faulted types and phases, rather than requiring an engineer to specify them. Simulation results have demonstrated the validity of the algorithm under the condition of a phase-to-earth fault
  205.   Sachdev, M.S., Das, R., Sidhu, T.S., 1999. Distribution-line shunt-fault locations from digital relay measurements. Canadian Journal of Electrical and Computer Engineering-Revue Canadienne de Genie Electrique et Informatique 24, 41-47.
Abstract: Estimating the location of transmission-line faults has been a subject of interest to electric power utility engineers and researchers for over 25 years. This paper presents a technique that estimates the location of a radial-distribution-line shunt fault from digital relay measurements. The method first estimates the apparent impedance from the fundamental-frequency voltage and current phasors measured by the relay. Intermediate load taps and nonhomogeneity of the line are taken into account. The load currents are estimated from static-response-type models. Single-phase as well as three-phase loads are modelled. The technique estimates the location of single-phase-to-ground, two-phase-to-ground, phase-to-phase and balanced three-phase faults. The estimate of the location of a fault is based on the apparent location of the fault the voltage-current relationship at the fault, and the fault impedance. An iterative approach is used to improve the accuracy of the estimation of the distance to the fault. The technique is described by means of an example considering the location of a phase-to-phase fault Similar procedures are used for other types of faults. Some test results are also reported
  206.   Sheng, L.B., Elangovan, S., 1999. A fault location method for parallel transmission lines. International Journal of Electrical Power & Energy Systems 21, 253-259.
Abstract: This paper presents a fault location method for one of two individually transposed parallel transmission lines. This method only utilizes voltage and current data acquired at one common end of the two lines to estimate the equivalent source impedance at the remote end. Therefore, the current through a fault resistance in the fault-path can be computed and the effects of the fault resistance and source impedance of the remote system on the accuracy of fault location can be eliminated. However, this method requires that: (1) a fault occurs only on one of the two parallel lines; and (2) the unfaulted line remains in operation until the fault is cleared. (C) 1999 Elsevier Science Ltd. All rights reserved
  207.   Thomas, D.W.P., Batty, R.E., Christopoulos, C., Wang, A.D., 1998. A novel transmission-line voltage measuring method. Ieee Transactions on Instrumentation and Measurement 47, 1265-1270.
Abstract: A novel transmission-line monitoring method for estimating the transient voltage from the transient current alone is presented. This is based on the properties of traveling waves instigated on high-voltage transmission lines as a result of a fault, switching operation, or a lightning strike. The method is unique in that superimposed voltage transients can be deduced without employing measurements taken from voltage transducers, It is demonstrated that full advantage can he made of the broad bandwidth of the current transducers to improve fault location and enable high-speed traveling wave protection to be applied on power systems
  208.   Liao, Y., Elangovan, S., 1998. Improved symmetrical component-based fault distance estimation for digital distance protection. Iee Proceedings-Generation Transmission and Distribution 145, 739-746.
Abstract: An improved symmetrical component-based method is proposed in the paper. The proposed method uses phasor estimates of voltage and current samples obtained from both ends of a transmission line. The mathematical basis of the new approach is described. It is shown that the new method completely obviates complex arithmetic operations and has considerable computational advantages over the previously proposed methods. Furthermore, performance assessment studies on this new method using the alternative transient program (ATP) are presented and discussed. It is illustrated that the proposed method can determine the fault location very accurately and is likely to be used for digital distance protection and fault location
  209.   Djuric, M.B., Radojevic, Z.M., Terzija, V.V., 1999. Time domain solution of fault distance estimation and arcing faults detection on overhead lines. Ieee Transactions on Power Delivery 14, 60-67.
Abstract: In this paper a new numerical algorithm for arcing faults detection and fault distance estimation is presented. The solution is given in time domain. It is based on the line terminal voltages and currents processing. A simple new mathematical model of are voltage is introduced in the estimation. Thereby, the more accurate approach to fault location is derived, particularly for the close-in faults. The new algorithm can be utilized for blocking the automatic reclosing. The unknown model parameters, including the line resistance and inductance, fault resistance and are voltage amplitude, are estimated by using Least Error squares Method. The new algorithm is successfully tested through computer simulation and laboratory tests
  210.   Funabashi, T., Otoguro, H., Mizuma, Y., Kai, T., Takeuchi, N., Akiyama, S., Dube, L., Ametani, A., 1999. Digital fault location for high resistance grounded transmission lines. Ieee Transactions on Power Delivery 14, 80-85.
Abstract: This paper demonstrates that the presence of multiple load taps cannot be neglected for single-phase-to-ground fault location. A new method has been developed taking this into consideration, that can be applied to correct the location error due to intermediate power sources. Then fault location methods for parallel double-circuit two-terminal transmission linesare discussed. Finally, a new fault location method is proposed for high-resistance grounded double-circuit transmission lines with three terminals
  211.   Xuan, Q.Y., Aggarwal, R.K., Johns, A.T., Dunn, R.W., Bennett, A., 1998. A neural network based protection technique for combined 275 kV 400 kV double circuit transmission lines. Neurocomputing 23, 59-70.
Abstract: The work described in this paper addresses the problems encountered by conventional distance relays when protecting double-circuit transmission lines comprising different voltage levels. The problems arise principally as a result of the mutual coupling between the two circuits under different fault conditions; this mutual coupling is highly nonlinear in nature. An adaptive protection scheme is proposed for such lines based on employing a neural network (NN). A NN has the ability to classify the nonlinear relationship between measured signals and the faulted zone by identifying different patterns of the associated voltages and currents. One of the key points of this paper is data preprocessing of the measured signals essentially to extract the most significant features from the signals. The adaptive protection scheme is tested under a specific fault type, but varying fault location, fault resistance, fault inception angle and different source capacities. All the test results clearly show that the proposed adaptive protection technique is well suited for double circuits with different voltage levels. (C) 1998 Elsevier Science B.V. All rights reserved
  212.   Sheng, L.B., Elangovan, S., 1998. A fault location algorithm for transmission lines. Electric Machines and Power Systems 26, 991-1005.
Abstract: This paper presents an algorithm for the computation of fault location for a transmission line by means of the voltage and current signals, acquired by the digital distance relays at both the terminals of the line. Based on the proposed algorithm, the fault distance can be calculated accurately and quickly, even though the two digital distance relays are of different types with different sampling frequencies. This proposed fault location method is suitable for the condition that there are communication links between a power grid dispatch centre and the digital distance relays
  213.   Liao, Y., Elangovan, S., 1998. Digital distance relaying algorithm for first-zone protection for parallel transmission lines. Iee Proceedings-Generation Transmission and Distribution 145, 531-536.
Abstract: The paper proposes a new digital distance relaying algorithm for first-zone protection for parallel transmission lines. The new method uses data from one end of the protected parallel lines to calculate the fault distance. It is shown that the new method is independent of fault resistance, remote infeed and source impedances. Extensive simulation studies using EMTP have verified that this approach can obtain a highly accurate fault distance estimation within one cycle after fault inception and hence is very much suitable for digital distance protection for parallel lines. Applications of this method for fault location are also presented
  214.   Djuric, M.B., Radojevic, Z.M., Terzija, V.V., 1998. Distance protection and fault location utilizing only phase current phasors. Ieee Transactions on Power Delivery 13, 1020-1026.
Abstract: Two numerical algorithms for fault location and distance protection which use data from one end of transmission line are presented. Both algorithms require only current signals as input data. Voltage signals are unnecessary for determining the unknown distance to the fault. The solution for the most frequent phase to ground fault is presented. The algorithms are relatively simple and easy to be implemented in the on-line application. The algorithms allow for accurate calculation of the fault location irrespective of the fault resistance and load. To illustrate the features of the new algorithms, steady-state and dynamic tests are presented
  215.   Zhang, Q.C., Zhang, Y., Song, W.N., Fang, D.Z., 1998. Transmission line fault location for single-phase-to-earth fault on non-direct-ground neutral system. Ieee Transactions on Power Delivery 13, 1086-1092.
Abstract: A new method for locating single-phase-to-earth fault on transmission line of non-direct ground neutral system is presented. The method employs the faulted phase network and zero-sequence network as the fault location model. It effectively eliminates the effect of load and fault resistance on the accuracy of fault location. The technique embodies an accurate location by measuring only one local end data. The method is used in a procedure that provides the automatic determination of faulted line and phase, rather than requires engineer to specify them. Simulation results have shown the effectiveness of the algorithm under the condition of earth fault
  216.   Lian, B., Salama, M.M.A., Chikhani, A.Y., 1998. A time domain differential equation approach using distributed parameter line model for transmission line fault location algorithm. Electric Power Systems Research 46, 1-10.
Abstract: The objective of this work is to develop an algorithm which can provide both a fast relaying time (1/4-1/2 cycles) and an accurate fault location (error within 1% of the total line length). The proposed algorithm combines the strengths of the two distinct approaches, namely, the steady-state phasor approaches (SSPA) and the differential equation approaches (DEA). In the proposed algorithm, a distributed line model is used, which is suitable for the short, the long, the transposed and the untransposed lines. The DEA is used to calculate the fault location and is implemented using the Laplace and the Z-transform techniques. There are several advantages in this proposed algorithm ever the existing ones: (a) the variations in the line parameters with the frequency are considered; (b) the fault location estimate is less sensitive to the selection of the sampling rate, the fault inception angle, the signal spectrum and the equivalent sources behind both bus bars; and (c) the relay performance is greatly improved offering both the desired high accuracy and the speed at the same time. (C) 1998 Published by Elsevier Science S.A. All rights reserved
  217.   Chang, C.S., Chen, J.M., Srinivasan, D., Wen, F.S., Liew, A.C., 1997. Fuzzy logic approach in power system fault section identification. Iee Proceedings-Generation Transmission and Distribution 144, 406-414.
Abstract: Great emphasis has been put on applying expert systems for transmission system fault diagnosis. However, very few papers deal with the unavoidable uncertainties that occur during operation involving the fault location and other available information. The paper proposes a method using fuzzy sets to cope with such uncertainties. A fuzzy expert system is developed, which requires much less memory to store an active database than that used by conventional rule-based expert systems. The fuzzy expert system identifies two basic network section sets, S-healthy for the healthy subnetwork and S-island for the fault islands, using the postfault status of circuit breakers and relays. It then conducts inference to determine the most likely fault sections and the associated fault sequences. Two case studies are provided to demonstrate salient features of the proposed approach, and to compare results both with a conventional rule-based expert system and a refined genetic algorithm. The proposed fuzzy expert system can be operated either in a stand-alone manner, or as part of the overall architecture of a diagnosis system for parallel decision making
  218.   Girgis, A.A., Sallam, A.A., El-Din, A.K., 1998. An adaptive protection scheme for Advanced Series Compensated (ASC) transmission lines. Ieee Transactions on Power Delivery 13, 414-420.
Abstract: This paper presents an adaptive protection scheme for Advanced Series Compensated (ASC) transmission lines. The scheme is based on Kalman and adaptive Kalman filters. The adaptive scheme utilizes the differences in the transient current signals for faults encountering and not encountering the ASC to determine the fault location with respect to the ASC and the faulted phases, Equations to determine the line impedance to the fault on these lines are developed, The adaptive scheme is tested for faults along and outside the protected line using EMTP simulated data
  219.   Djuric, M.B., Terzija, V.V., Radojevic, Z.M., 1998. Overhead lines fault location and arc voltage estimation numerical algorithm derived in time domain. Electrical Engineering 81, 45-53.
Abstract: A new fault location numerical algorithm based on terminal data and derived in time domain is presented. The fault location and its nature (arcing or arcless fault) are estimated using least error squares technique. The faulted phase voltage is modelled as a serial connection of fault resistance and are voltage. The new approach does not require the line zero sequence resistance as an input datum. In the paper some important features of are voltage are given. The algorithm is derived for the most frequent case of single-phase line to ground unsymmetrical fault. The results of algorithm testing by computer simulation and under laboratory conditions are given. The influences of remote infeed, fault resistance, higher order harmonics, network topology and other factors are investigated and presented
  220.   Handschin, E., Kuhlmann, D., Westermann, D., 1997. ANN-based measuring algorithms for power system protection. Engineering Intelligent Systems for Electrical Engineering and Communications 5, 205-211.
Abstract: During the last years a lot of research activities have been directed to point out the properties of Artificial Neural Networks (ANN) for applications in the field of electric power engineering. A survey of the use of ANN for the realization of powerful measuring algorithms with special interest in power system protection is presented in this paper. After a brief description of requirements for modern power protection systems different application areas for ANN in the field of signal processing, fault classification and fault location are discussed. All these methods are related to measuring algorithms for power system protection
  221.   Aggarwal, R.K., Joorabian, M., Song, Y.H., 1997. Fuzzy neural network approach to accurate transmission line fault location. Engineering Intelligent Systems for Electrical Engineering and Communications 5, 251-258.
Abstract: This paper describes an accurate fault location technique using fuzzy neural networks (FNN). The technique, which utilises voltage and current fault data at one line end only, comprises of two stages: the first stage is based solely on an artificial neural network (ANN) in order to classify fault types and the second stage is based on an FNN whereby fuzzy logic is employed to train a second ANN for the purposes of accurately locating a fault on the line. It is clearly shown that with this integrated approach, the accuracy in fault location is significantly improved over other techniques solely based on an ANN architecture
  222.   Teo, C.Y., 1997. A comprehensive fault diagnostic system using artificial intelligence for sub-transmission and urban distribution networks. Ieee Transactions on Power Systems 12, 1487-1493.
Abstract: This paper describes an intelligent diagnostic system for an interconnected distribution network developed to assist the system operator with fault identification during restoration. The intelligent process utilizes only those data available in a standard SCADA system such as the post fault network status, the list of the tripped breakers, main protection alarm, and the conventional event log. The fault diagnostic system is implemented by three independent mechanisms, namely the generic core rule, the generic relay setting inference and the specific post-fault network matching and learning. The generic core rule generates various possible fault locations and the generic relay inference examines whether each possible fault location is logical and valid. The specific network matching compares whether the post fault network and the related tripped breakers are identical to a previous fault event. Test results obtained from two distribution networks confirm that the developed system is practical, reliable and accurate
  223.   Chang, C.S., Chen, J.M., Liew, A.C., Srinivasan, D., Wen, F.S., 1997. Fuzzy expert system for fault diagnosis in power systems. Engineering Intelligent Systems for Electrical Engineering and Communications 5, 75-81.
Abstract: Fault diagnosis of power system plays a crucial role in power system monitoring and control that ensures a stable supply of electrical power to consumers. In the case of multiple faults or incorrect operation of protective devices, fault diagnosis requires judgment of complex conditions of various levels, especially considering the unavoidable uncertainties that occur during operation involving the fault location and other information available. This paper presents a methodology for fault diagnosis far complex electrical power systems, which is based on fuzzy logic and expert system to deal with the uncertainties. Expert knowledge concerning normal and faulted operation is acquired via knowledge acquisition techniques. A fuzzy logic expert system for fault diagnosis of power system is developed which uses as input status change of the operated circuit breakers and relays. The fuzzy expert system requires much less memory space to stare active databases than those used by conventional expert systems. The fuzzy expert system first identifies a short list of possible fault sections and deals with one possible fault section at a time. It then conducts inference to determine the most likely fault sections and the associated fault section sequences. Several study cases are given in this paper to demonstrate salient features of the proposed method
  224.   Lian, B., Salama, M.M.A., Hanson, J., 1997. Identifying an error source in the differential equation approach for the transmission line fault location algorithm. Electric Power Systems Research 42, 115-119.
Abstract: An overlooked error source in the differential equation approach for locating a fault on a transmission line is investigated. Due to the use of difference equations in the expansion of the differential equation, a mismatch results between the different transfer functions in the frequency domain that are applied to different terms in the same equation, causing an error in the final fault location estimate. This error source is identified and its effect on the fault location estimate is shown through numerical simulation. A criterion is proposed for improving the difference approximation. (C) 1997 Elsevier Science S.A
  225.   Aggarwal, R.K., Aslan, Y., Johns, A.T., 1997. New concept in fault location for overhead distribution systems using superimposed components. Iee Proceedings-Generation Transmission and Distribution 144 , 309-316.
Abstract: Due to the challenges facing many utilities worldwide as a result of deregulation, the demand and importance of accurate fault location in distribution Systems has increased, principally to minimise line outages through effecting repairs expeditiously. The paper presents a novel approach in single-ended fault location for overhead distribution systems based on the concept of superimposed voltages and currents. It is clearly shown that the technique, which is interactive in nature, is highly robust to changes in local and remote source capacities and to the presence of load taps
  226.   Lyamets, Y.Y., Ilin, V.A., Podshivalin, N.V., 1996. Fault location in transmission lines. Electrical Technology 101-112.
Abstract: The paper describes a new concept for analysing digital dynamic records of transmission line faults and introduces a transmission line fault location system. Three functional blocks control transmission line fault identification. The first one controls adaptive filtering; the second block controls the evaluation of parameters; the third one controls revision of a priori information according to service data. The concept considered is developed as a program package to be used together with transmission line fault recorders. Results of processing line faults in the Chuvashenergo and Saratovenergo networks are given. (C) 1997 Elsevier Science Ltd. All rights reserved
  227.   Ibrahim, E.S., 1997. Impact of fault allocation and stray capacitance on turbo-generator units connected to series compensated transmission lines. International Journal of Electrical Power & Energy Systems 19, 111-118.
Abstract: This paper examines transient torque phenomena which can arise in the shaft systems of large synchronous generators connected to series compensated transmission lines, following a system disturbance. 1L-G, 2L-G and three phase faults are studied along with the location of the fault. Results relating to peak shaft torque at various turbine, generator and exciter interfaces as a function of the duration of the applied three phase short circuit are considered, at full load and at no load. The effects of stray capacitance on torsional oscillations and its method of representation are studied to identify the torsional interaction conditions and to determine its zones on the system behaviour at full load and at no load. Copyright (C) 1996 Elsevier Science Ltd
  228.   Sumida, M., Furukawa, S., Tanaka, K., Aiki, M., 1996. High-accurate fault location technology using FSK-ASK probe backscattering reflectometry in optical amplifier submarine transmission systems. Journal of Lightwave Technology 14, 2108-2116.
Abstract: This paper proposes a new modulation format for optical time domain reflectometry (QTDR) to eliminate optical surge and improve OTDR performance in optical amplifier submarine transmission systems. The modulation format, FSK-ASK, uses a short high-power probe pulse and a long dummy pulse. Thanks to the slow gain dynamics of erbium-doped fiber amplifiers, both pulses experience an identical gain, equal to the loss of a span, so that the probe pulse maintains its high power and does not develop into an optical surge. Fault location experiments verify a theoretical prediction that FSK-ASK improves the signal-to-noise ratio (SNR) of OTDR by an amount as large as the power ratio of the probe to dummy signal. They also confirm the elimination of the optical surge caused by conventional OTDR using a solitary probe pulse. An FSK-ASK OTDR is applied in a commercial submarine amplifier transmission system which has a total transmission length of 890 km and a repeater spacing of 90 km. These field trial results show that subtle fiber anomalies can be located, with a spatial resolution of 1 km, along the entire length of the amplifier transmission system from a terminal end
  229.   Minambres, J.F., Zamora, I., Mazon, A.J., Zorrozua, M.A., AlvarezIsasi, R., 1996. A new technique, based on voltages, for fault location on three-terminal transmission lines. Electric Power Systems Research 37, 143-151.
Abstract: A new method for fault location on three-terminal transmission lines is described in this paper. Through this method, the faulty line branch is determined and the fault point located in a reliable and simple manner. For this, to reduce mathematical errors, a complete line model including the various characteristics of the network is used and a simple calculation method is applied, based on a new concept referred to as the 'branch factor'. The method only uses the main components (50/60 Hz) of fault and prefault voltage values measured at the three terminals of the transmission line. Moreover, this method is independent of the fault and prefault current, type of fault and fault resistance, as well as the synchronization of recording devices located at the three terminals of the transmission line, and the prefault conditions. This paper also reviews the sensitivity of this method to errors in input data
  230.   Sumida, M., Amemiya, M., Furukawa, S., Tanaka, K., 1996. optical amplifier Fault location on submarine transmission systems. Electronics and Communications in Japan Part I-Communications 79, 1-10.
Abstract: This paper addresses some solutions to overcome the problems that arise when optical time domain reflectometry (OTDR) is applied to optical amplifier submarine transmission systems. It designs a backscatter path that feeds the backscattering into the opposite line without causing any degradation in the main signal transmission. This paper proposes a new modulation format, FSK-ASK, and confirms that the proposed approach can both eliminate optical surge generation and improve OTDR performance. An FSK-ASK OTDR is applied to an 890-km commercial amplifier submarine transmission system with a 90-km span. Field trials successfully demonstrate that the OTDR can locate a fault in all spans with a spatial resolution of 1 km after averaging the sum of 2(20) measurements. The FSK-ASK OTDR proves to be very useful in maintaining a reliable submarine transmission system because it can locate subtle fiber anomalies along the entire length from a terminal end
  231.   Khaparde, S.A., Warke, N., Agarwal, S.H., 1996. An adaptive approach in distance protection using an artificial neural network. Electric Power Systems Research 37, 39-44.
Abstract: All relay settings are a compromise. Adaptive relaying accepts that relays that protect a power system may need to change their characteristics to suit the prevailing power system conditions. This philosophy has a wide range of applications covering many protective schemes. Here we consider a two-terminal transmission line, confirm that fault resistance and the location of faults can produce erroneous relay function and finally suggest ways to ensure the generation of the correct signal for relay operation. Retaining the microprocessor based framework, we show how artificial neural networks (ANNs) can be used effectively to achieve adaptive relaying for the above-mentioned problem. Adaptive relaying covers a large number of applications and the characteristics of relays vary widely, so the philosophy of adaptive relaying must vary accordingly. A modified multilayered perceptron model employs an additional node in the input layer. This additional input facilitates changes in the relay characteristic. The desired change in the quadrilateral relay characteristic is achieved by making appropriate changes in the thresholds and weights of the hidden layer neurons. A multiparameter adaptive scheme assumes that the additional input of the phase angle is available. Simulation results using ANNs for the different applications of adaptive relaying mentioned above are presented and discussed
  232.   Mazon, A.J., Minambres, J.F., Zorrozua, M.A., Zamora, I., AlvarezIsasi, R., 1995. New method of fault location on double-circuit two-terminal transmission lines. Electric Power Systems Research 35, 213-219.
Abstract: A new method to locate faults on double-circuit transmission lines is described in this paper. This method only uses the fundamental components (50/60 Hz) of fault and prefault currents, measured at one of the ends of the line. From these measured values a function is established from which the point at which a fault occurred is determined. The definition of a new concept called the 'distance factor' will allow a method to be developed which is independent of fault resistance, type of fault, mutual coupling between the two circuits and initial prefault conditions. The accuracy of this method has been assessed by using a fault simulation software program. In the first stage the accuracy of the method was determined on the basis of accurate input data. In the second stage the sensitivity of the method was analyzed from errors in the input data
  233.   Zamora, I., Minambres, J.F., Mazon, A.J., AlvarezIsasi, R., Lazaro, J., 1996. Fault location on two-terminal transmission lines based on voltages. Iee Proceedings-Generation Transmission and Distribution 143, 1-6.
Abstract: A new method for locating faults in two-terminal transmission lines is discussed. The procedure is based on the fundamental components of fault and prefault voltage at 50/60Hz measured at the two ends of a transmission line. The methodology allows one to establish a direct calculation procedure that is independent of fault and prefault currents, fault type, fault resistance, synchronisation condition of register devices located on line ends, and prefault condition, either balanced or not. This is achieved by defining a new concept called 'distance factor'. The technique developed was validated at two levels: first, from exact data obtained using a fault simulation software program, which allows the accuracy to be evaluated, and secondly, from erroneous voltage data taken at the ends of the line or from erroneous source impedances, which allows assessment of the sensitivity against incorrect data
  234.   Kezunovic, M., Perunicie, B., 1996. Automated transmission line fault analysis using synchronized sampling at two ends. Ieee Transactions on Power Systems 11, 441-447.
Abstract: This paper introduces a new approach to fault analysis using synchronized sampling. A digital fault recorder with Global Positioning System (GPS) satellite receiver is the source of data for this approach. Fault analysis functions, such as fault detection, classification and location are implemented for a transmission line using synchronized samples from two ends of a line. This technique can be extremely fast, selective and accurate, providing fault analysis performance that can not easily be matched by other known techniques
  235.   Novosel, D., Hart, D.G., Udren, E., Garitty, J., 1996. Unsynchronized two-terminal fault location estimation. Ieee Transactions on Power Delivery 11, 130-138.
Abstract: A technique for fault location estimation which uses data from both ends of the transmission line and which does not require the data to be synchronized is described. The technique fully utilizes the advantages of digital technology and numerical relaying which are available today and can easily be applied for off-line analysis. This technique allows for accurate estimation of the fault location irrespective of the fault type, fault resistance, load currents, and source impedances. Use of two-terminal data allows the algorithm to eliminate previous assumptions in fault location estimation, thus increasing the accuracy of the estimate. The described scheme does not require real time communications, only off-line post-fault analysis. The paper also presents fault analysis techniques utilizing the additional communicated information
  236.   Lian, B., Salama, M.M.A., 1996. An overview of the digital fault location algorithms for the power transmission line protection based on the steady-state phasor approaches. Electric Machines and Power Systems 24, 83-115.
Abstract: The fault location algorithm is a key element in the digital relay for power transmission line protection. The core of the algorithm is the relaying function which relates the fault distance to the sampled waveforms. Various relaying functions are used, so far, based mainly on the steady-state phasor approach, the differential equation approach and the traveling-wave approach, respectively. In this paper, the steady-state phasor approaches are reviewed. The effect of various algorithms on relay speed and accuracy is examined regarding the selection of the system model, the relaying function and the filtering technique
  237.   Nagasawa, T., Deno, K., Yoshimi, M., Matsunaga, K., Itou, K., 1995. New Current Differential Protection and Fault-Location Scheme for Multiterminal Lines. Electrical Engineering in Japan 115, 10-21.
Abstract: This paper presents a new scheme of protection and fault location in multiterminal high-voltage lines. The new protection scheme is PCM (Pulse Code Modulation) current differential protection using OPGW (Optical Fiber Ground Wire). This scheme can be applied to protection up to 8-terminal transmission lines. This scheme has coped with the miss trip in the cause of CT-saturation. But this may have an opposite result, i.e., obstruction of trip during 4-cycle. Then, the index to cope with the miss trip for CT-saturation is proposed. The aforementioned system obtains various information at each terminal (e.g., current data and CB-condition, et al.). Then, a fault location scheme is developed using this information. It has two kinds of techniques using the synchronized current data of multiterminal lines. One technique is to measure the current diversion ratio with current of each terminal. The other technique is to measure impedance using current of each terminal and voltage. This scheme can automatically choose between the two technique at fault type. The equipment using this scheme has obtained a good result in the field
  238.   Chen, Y.K., Guo, W.Y., Way, W.I., Chi, S., 1995. In-Service Supervisory Edfa-Repeated Wavelength-Division Multiplexing Transmission-System. Ieee Photonics Technology Letters 7, 923-925.
Abstract: An in-service supervisory wavelength division multiplexing (WDM) transmission system is demonstrated for the first time. Simultaneous fault location and EDFA status-monitoring are achieved without degrading the 2.5 Gb/s service in a five-EDFA, 365-km, four-WDM-channel system
  239.   Yamamoto, M., Ifukube, A., Murata, Y., Hashimoto, M., 1995. Development of Fault Detector for 33-Kv Ungrounded Power-Line. Electrical Engineering in Japan 115, 71-81.
Abstract: A fault section detection system is being developed for 33-kV ungrounded power line. The fault section is obtained from the relation of two point zero-phase currents on power line. This fault detector is composed of optical current sensors and the processing unit and solar battery system. The optical current sensor consists of a Faraday cell and a porcelain bushing. Zero phase current on the processing unit is obtained through a three-phase composer with auto gain control and residual current eliminator. This fault detector has the ability of 0.15 A zero-phase current detection fault factory test; in field tests, this fault detector detects ground fault
  240.   Mihalic, R., Zunko, P., 1995. Phase-Shifting Transformer with Fixed Phase Between Terminal Voltage and Voltage Boost - Tool for Transient Stability Margin Enhancement. Iee Proceedings-Generation Transmission and Distribution 142, 257-262.
Abstract: The development of power electronics has enabled rapid and nearly continuous control of phase-shifting transformers (PSTs). As a consequence, new possibilities for solving problems concerning not only steady-state but also dynamic conditions in power systems are offered by electronically controlled PSTs. In the paper the basic operating principles of a PST with fixed phase between terminal voltage and voltage boost (FP-PST) are presented. A mathematical model of a FP-PST is introduced, which is a representation of a longitudinal transmission system with a FP-PST included. It is shown that the location and the orientation of a FP-PST have a crucial impact on the behaviour of the power system. For the chosen test system, by applying the mathematical model, the most suitable location and orientation of a FP-PST were determinated to solve problems concerning the first swing stability. On the same basis, appropriate FP-PST control is introduced to ensure the maximal stability margin for given FP-PST dimensions, small back swing and effective damping of subsequent swings. Modelling of the test system and FP-PST and dynamic simulation were performed in the stability mode of the NETOMAC program system. The minimal dimensions of a FP-PST were determined to ensure that the system remains stable after a fault followed by line tripping. Finally, the results of the dynamic simulation are presented
  241.   Waikar, D.L., Liew, A.C., Elangovan, S., 1995. 2Nd-Zone and 3Rd-Zone Performance Assessment of A Symmetrical Component Based Improved Fault Impedance Estimation Method. Electric Power Systems Research 32, 113-120.
Abstract: The performance assessment of a symmetrical component based fault impedance estimation method that has previously been proposed by the authors is discussed in this paper. A brief review of the proposed method is given. The personal computer based Alternative Transient Program was used in these performance assessment studies. Voltage and current signals for various fault conditions were generated by simulating different types of fault on a selected transmission line of a sample power system. These signals were processed, sampled, and used in the proposed method. The apparent impedance of the protected transmission line from the relay location up to the fault point was calculated using the proposed method. These impedance estimates were inserted in R-X plane characteristics to determine the suitability of the proposed method for digital distance protection of the second and third zones. The results of these performance assessment studies are presented and discussed in the paper
  242.   Johns, A.T., Moore, P.J., Whittard, R., 1995. New Technique for the Accurate Location of Earth Faults on Transmission-Systems. Iee Proceedings-Generation Transmission and Distribution 142, 119-127.
Abstract: A new technique for single-ended location of resistive earth faults on transmission lines is presented. Unlike previous work, the algorithm developed has inherent insensitivity to setting errors in the remote source impedance value. This is an important feature, since the remote source impedance often varies significantly under operational conditions. The paper shows the theoretical development of the algorithm, together with a detailed consideration of the hardware aspects. Results are presented for a standard 400 kV transmission line application study
  243.   Abe, M., Otsuzuki, N., 1995. Development of A New Fault Location System for Multiterminal Single Transmission-Lines. Ieee Transactions on Power Delivery 10, 159-168.
Abstract: Conventional fault location systems which use one-terminal ac voltages and currents are difficult to apply to multi-terminal systems. This paper discusses a new fault location system for multi-terminal single;transmission lines. Asynchronous sampling at each terminal is preferred in order to simplify the transmission equipment and an algorithm for synchronizing the asynchronous sampling data is presented. Another algorithm is presented which converts the original multi-terminal system by progressively conversion to a system with one fewer terminals to arrive at a a-terminal system containing the fault. An effective fault locating system can be constructed by combining these algorithms with existing reactive power locating operations. EMTP simulation results are presented
  244.   Chen, Y.K., Guo, W.Y., Way, W.I., Chi, S., 1994. Simultaneous In-Service Fault-Locating and Edfa-Monitoring Supervisory Transmission in Edfa-Repeatered Systems. Electronics Letters 30, 2145-2146.
Abstract: In-service WDM-based supervisory transmission in four/five EDFA-repeater 375km/365km systems is demonstrated. Simultaneous EDFA status-monitoring and fibre fault location are achieved without degrading the 2.5Gbit/s service
  245.   Tanaka, K., 1994. Multifault Calculation Method for Dynamic Stability Study of Electric-Power Systems. Electrical Engineering in Japan 114, 68-81.
Abstract: For the fault condition in dynamic stability study, balanced faults have mainly been utilized. Recently, however, with the progress of system protective control technologies such as the multiphase reclosing system for a faulted transmission line, the needs for stability software which would be able to calculate simultaneous faults without any restrictions on fault types, total numbers or location, have been increasing
  246.   Inoue, N., Tsunekage, T., Sakai, S., 1994. Online Fault Location System for 66Kv Underground Cables with Fast O/e and Fast A/D Technique. Ieee Transactions on Power Delivery 9, 579-584.
Abstract: A fault location system, which continuously monitors a 66-kV underground transmission line and instantaneously locates the distance to the point of fault at a ground fault, is being developed. A prototype system for straight lines was developed as the first step. The surge current which flows, at a ground fault, from the point of fault to each end of the line is detected by a fast optical CT based on Faraday effect. The detected surge current is converted to digital data through a fast O/E converter and a fast A/D converter, and the distance to the point of fault is determined from the time difference of arrival of surge currents to both ends. Location test was carried out on single phase coaxial cable of 1000 m long. The average location error of the system is below 10 m
  247.   Kezunovic, M., Mrkic, J., Perunicic, B., 1994. An Accurate Fault Location Algorithm Using Synchronized Sampling. Electric Power Systems Research 29, 161-169.
Abstract: This paper introduces new fault location algorithms based on synchronized sampling. A time domain model of a transmission line is used as a basis for the algorithm development. Samples of voltages and currents at the ends of a transmission line are taken synchronously and used to calculate fault location. The paper discusses two different algorithm forms utilizing two line models. A number of tests are performed using EMTP simulations of faults. The algorithm results show high accuracy while the computational burden is moderate
  248.   Ancell, G.B., Pahalawaththa, N.C., 1994. Maximum-Likelihood-Estimation of Fault Location on Transmission-Lines Using Traveling Waves. Ieee Transactions on Power Delivery 9, 680-689.
Abstract: An improved method for fault location on transmission lines using the maximum likelihood estimate of the arrival times of reflected travelling waves is presented. The method is compared with previously proposed correlation based methods using results determined by ATP. The effectiveness of the new method for small fault angles and close in faults has been detailed
  249.   Lian, B., Salama, M.M.A., 1994. An Overview of Digital Fault Location Algorithms for Power Transmission-Lines Using Transient Wave-Forms. Electric Power Systems Research 29, 17-25.
Abstract: A digital fault location algorithm for calculating the fault distance on a power transmission line can be designed using any of three approaches: the steady-state phasor approach, the differential equation approach and the travelling-wave approach. In this paper, the algorithms utilizing the differential equation and the travelling-wave approach are reviewed. The effect of various algorithms on the relay speed and accuracy is examined. The associated filtering techniques are discussed
  250.   Lai, Y.W., Chen, Y.K., Way, W.I., 1994. Novel Supervisory Technique Using Wavelength-Division-Multiplexed Otdr in Edfa Repeatered Transmission-Systems. Ieee Photonics Technology Letters 6, 446-449.
Abstract: A wavelength-division-multiplexed optical-time-domain-reflectometry (OTDR) supervisory technique is experimentally demonstrated in a 200-km transmission system. The technique can simultaneously achieve in-line EDFA performance monitoring and diversity protection, and fault location in optical fibers
  251.   Sobral, S.T., Novaes, E.O., Coelho, A.S.R., 1993. Improvement of Transmission-Line Ground Circuit Current-Carrying Limit After System Interconnections. Ieee Transactions on Power Delivery 8, 2023-2030.
Abstract: When one or more transmission lines are added to an existing transmission system, the intensity Of the fault currents flowing along the ground wires near the substations may exceed the ground wire thermal limit. In such cases, it is generally preferred to improve the existing ground wire conductivity by replacing, say a steel ground wire with an ACSR ground wire along the first spans near the substation. Generally, this procedure requires that the transmission line be de-energized, what may sometimes be considered unacceptable. This paper deals with optional procedures which can be implemented in the first line kilometers near the substations keeping the existing lines energized. Such procedures include sectionalizing of ground wires, use of continuous counterpoise and use of additional overhead ground wires installed below the conductors. This paper introduces also a technique called by us ''tower foot resistance adjustment'', which complements the corrective effects of the mentioned procedures. The extension of the ''Decoupled Method'' [5,6,4,3,2,7,1] to represent the above suggested procedures is detailed in this paper which also includes a practical example occurred when the 220 kv Paraguayan system was connected to the Itaipu Collector System. The existing 220 kV lines have steel ground wires and leave the Acaray 250 MW Hydroelectric Power Plant. These transmission lines have been designed some 20 years ago to feed the main 220 kV Paraguayan network, i. e., a long time before the itaipu Power Plant location studies had been started. The connection between the Itaipu System and the Paraguayan System is presently done by two 5 km long 220 kV transmission lines, (L-1) and (L-2) having ACSR ground wires, as shown in Figure 1
  252.   Aggarwal, R.K., Coury, D.V., Johns, A.T., Kalam, A., Nilsson, S.L., 1993. A Practical Approach to Accurate Fault Location on Extra-High-Voltage Teed Feeders. Ieee Transactions on Power Delivery 8, 874-883.
Abstract: This paper describes the basis of an alternative approach for accurately locating faults on teed feeders and the technique developed utilises fault voltages and currents at all three ends. The method is virtually independent of fault resistance and largely insensitive to variations in source impedance, teed and line configurations, including line untransposition. The paper presents the basic theory of the technique which is then extensively tested using simulated primary system voltage and current waveforms which in turn include the transducer/hardware errors encountered in practice. The performance clearly shows a high degree of accuracy attained
  253.   Elhami, M., Lai, L.L., Daruvala, D.J., Johns, A.T., 1992. A New Traveling-Wave Based Scheme for Fault-Detection on Overhead Power Distribution Feeders. Ieee Transactions on Power Delivery 7, 1825-1833.
Abstract: This paper presents the results of investigations into a new fault location technique for overhead power distribution systems. The scheme is based upon detecting fault-induced high frequency components on distribution lines. This should enable the detection of discharges from the low-level breakdown of insulators, which can not be detected by conventional methods. The location of a fault is determined by appropriate signal processing of the fault generated signals on the line. Simulation results are used to illustrate the basic features of the performance of the new scheme on a simple radial 11kV feeder system
  254.   Youssef, O.A.S., 1992. A Fundamental Digital Approach to Impedance Relays. Ieee Transactions on Power Delivery 7, 1861-1870.
Abstract: This paper presents a new algorithm for computing transmission line impedances by digital methods. It describes a new technique for developing a digital filter which has the following features : 1- It eliminates harmonic as well as nonharmonic transient components (with unknown frequencies) in the system voltages and currents. 2- It effectively removes the dc-offset transient component. 3- It explicitly takes account of the dc decay rate which is affected by the effective resistance of the system and the resistance of the arc at the fault location. 4-The frequency response is highly selective as compared to other techniques presented before. 5- The size of the data window required for the computational algorithm is 1.0625 power frequency cycle. The proposed technique is used to calculate impedances of a transmission line from fault data available at a power system bus. One of the techniques presented before (Fourier) was selected as a reference of comparison with the new technique to indicate the degree of improvement which has been achieved on the impedance measurements. The technique was tested using simulated data generated from a software program, and data recorded at a 220-kV switching station. Some of the test results are included
  255.   Girgis, A.A., Fallon, C.M., 1992. Fault Location Techniques for Radial and Loop Transmission-Systems Using Digital Fault Recorded Data. Ieee Transactions on Power Delivery 7, 1936-1945.
Abstract: This paper presents digital fault location techniques for transmission systems when digital fault recorded data is available at one terminal or two terminals. The systems under consideration are a 115 kV loop transmission system with data available at two terminals and a 69 kV radial transmission system with data available at one terminal. The data under consideration were recorded using digital fault recorders. This paper shows the conversion of the data to workable data files and the techniques developed to achieve the highest accuracy in determining the fault location. Intermediate load buses and loads are considered in determining the fault location. An example of the effect of neglecting the presence of these loads is discussed. The fault location techniques are based on both the apparent impedance concept and the use of the three-phase voltage and current phasors. A test case with the exact fault location is presented. The techniques were developed on an IBM PC
  256.   Lawrence, D.J., Cabeza, L.Z., Hochberg, L.T., 1992. Development of An Advanced Transmission-Line Fault Location System .1. Input Transducer Analysis and Requirements. Ieee Transactions on Power Delivery 7, 1963-1971.
Abstract: As part of the development of an advanced, more consistently accurate transmission line fault location system (AFLS), an evaluation of the performance and requirements for voltage and current input transducers was made. Measurements of CT and CCVT burdens were made, and computer models of the steady-state and transient responses were developed. Burdens from the existing electromechanical relaying and metering equipment in the secondary circuits were found to be large enough to cause transient distortion of the current waveforms for some fault cases, and would not meet the stringent requirements for an AFLS. A recommendation was made to place the AFLS in the primary relaying circuits, where electronic relays having low burdens are installed
  257.   Lawrence, D.J., Cabeza, L.Z., Hochberg, L.T., 1992. Development of An Advanced Transmission-Line Fault Location System .2. Algorithm Development and Simulation. Ieee Transactions on Power Delivery 7, 1972-1983.
Abstract: This paper describes the solution techniques, system modeling considerations, and simulation studies performed as a part of the development of an advanced transmission line fault location system (AFLS) intended for use on the New York Power Authority's system. The Power Authority's Moses-Adirondack 230 kV lines were selected as a test bed for the study. A reduced model of the transmission system around the Moses-Adirondack lines was developed, and a number of Electromagnetic Transients Program (EMTP) cases run to establish simulated voltage and current information as fed to the fault location system. Sensitivity studies were performed to investigate the impact of various system models, hardware features, and system conditions on fault location accuracy
  258.   Ancell, G.B., Pahalawaththa, N.C., 1992. Effects of Frequency-Dependence and Line Parameters on Single Ended Traveling-Wave Based Fault Location Schemes. Iee Proceedings-C Generation Transmission and Distribution 139, 332-342.
Abstract: The effects of frequency dependence, line asymmetry, and varying ground conductivity on ultrahigh speed, travelling wave based, single ended, protection schemes are investigated in this paper. Typical schemes assume the transmission lines to be balanced and frequency independent which simplifies the analysis of the fault transients. Investigation of a single circuit vertically configured transmission line reveals that better results can be obtained by using modal parameters based on the configuration of the transmission line. The problem of modal mixing at discontinuities on the transmission line is demonstrated in the case of an unbalanced line to ground fault. The results described in this paper have applications in both protection and fault location schemes
  259.   Nagasawa, T., Abe, M., Otsuzuki, N., Emura, T., Jikihara, Y., Takeuchi, M., 1992. Development of A New Fault Location Algorithm for Multiterminal 2 Parallel Transmission-Lines. Ieee Transactions on Power Delivery 7, 1516-1532.
Abstract: Conventional fault location methods using one-terminal ac voltage and current are not applicable to multi-terminal systems. This paper describes a new fault location algorithm for multi-terminal two parallel transmission lines. This method uses the magnitude of the differential currents at each terminal and also uses an algorithm based on a 3-terminal fault location algorithm and an equivalent conversion from an n-terminal to a 3-terminal system. For a multi-fault occurring at the same place and same time on both lines as well as a single-fault this new algorithm is reasonably accurate. EMTP simulation results are shown
  260.   Youssef, O.A.S., 1992. A New Technique for Location of Transmission-Line Faults Using Single-Terminal Voltage and Current Data. Electric Power Systems Research 23, 123-128.
Abstract: This paper presents a new technique for location of transmission line faults using voltage and current measurements from one end of the faulted line. The method differs from past techniques in many respects. The main feature of the new technique is that it considers the influence of the remote-end infeed of the transmission line, the effect of the transmission line capacitance, fault resistance, prefault loading conditions, and the effect of mutual coupling between different phases of the line, and then computes with a microprocessor the distance to the fault point without any approximations. It uses recorded phase voltages and currents at the near end, then the fundamental components of the measured signals are extracted using microprocessor filters. The modal values of the extracted signals are computed then processed to indicate the precise location of the fault
  261.   Iliceto, F., Gatta, F.M., Cinieri, E., Asan, G., 1992. Trvs Across Circuit-Breakers of Series Compensated Lines Status with Present Technology and Analysis for the Turkish 420-Kv Grid. Ieee Transactions on Power Delivery 7, 757-766.
Abstract: The paper deals with analysis of TRVs across circuit breakers of EHV lines, compensated with modern series capacitors protected by varistors. It updates the applicable measures for limiting TRVs with present station equipment technology. A physical explanation of the phenomenon is presented first. This is useful for classifying the series compensation transmission schemes on the basis of the TRV magnification they can cause. It is also shown that series capacitors protected by varistors result in higher TRVs than capacitors protected by spark-gaps, because trapped charge voltage remains on the capacitors following clearing of faults of any type and location. Simplified formulas are provided for a quick approximate estimation of TRVs. Means are reviewed for limiting TRVs (opening resistors, by-passing of capacitors, surge arresters, etc.). An attractive and novel solution is explored, namely varistors branched across line breaker contacts. Results are presented of EMTP TRV analysis performed for three groups of series compensated 420-kV lines in Turkey, and a description is given of measures applied for limiting TRVs. It is also shown that line outage contingency cases and line fault clearing by breaker failure protection may cause a magnification of TRVs, to which attention must be paid
  262.   Sato, K., Atsumi, S., Shibata, A., Kanemaru, K., 1992. Power Transmission-Line Maintenance Information-System for Hokusei Line with Snow Accretion Monitoring Capability. Ieee Transactions on Power Delivery 7, 946-951.
Abstract: A new maintenance information system for overhead power lines was developed and put into practical use in assuring a stable and reliable supply of electrical power. By using tension sensors, various kinds of meteorological sensors, and TV cameras, this system regularly monitors snow accretion on power line running though snowy mountainous areas. Sensor data are transmitted through optical fibers within the composite fiber optic overhead ground wire. The central monitoring equipment performs distributed processing using several personal computers to share the tasks effectively. This system is considered as a model of future power line maintenance information systems and is therefore developed as a generalized system including both fault location and a data acquisition scheme from control processors of dispatching facilities. This system has been operating satisfactorily since July, 1990, summer through winter. This paper describes the system and its performance - especially with regard to snow-accretion monitoring and fault location. This system is expected to contribute to both the assurance of a reliable power supply and the effective maintenance of power lines
  263.   Sato, Y., Aoyama, K., 1992. Optical-Time Domain Reflectometry in Optical-Transmission Lines Containing In-Line Er-Doped Fiber Amplifiers. Journal of Lightwave Technology 10, 78-83.
Abstract: Optical time domain reflectometry (OTDR) in an optical transmission line containing in-line Er-doped fiber amplifiers is investigated. The proposed Er-doped fiber amplifiers are based on optical circulators, which support both OTDR and digital signal transmission. The measurable limit of OTDR fault location in optical transmission lines containing in-line amplifiers is discussed. Fault location and 1.8-Gb/s digital signal transmission are demonstrated in a 316.9 km, optical transmission line constructed with three in-line Er-doped fiber amplifiers
  264.   Tsuji, K., Yanagida, H., Sasaki, H., Abe, S., 1992. Development of Fault Characterization Equipment (Fcarec) for Power Transmission-Lines. Ieee Transactions on Power Delivery 7, 133-138.
Abstract: This paper presents fault characterization equipment (FCAREC) which detects fault resistances in a time sequence, in addition to the conventional determination of fault location. The objective of FCAREC is to offer improved functions to estimate causes of system faults. The equipment works by solving a circuit equation, using voltage and current data and line constants at each end of a particular line. To reduce the effects of data measurement errors, a high-precition calculation based on the least squares method is used. Since December 1989, the prototype FCAREC equipment has been used in feasibility tests on 154kV parallel double transmission lines. During the tests, three power system faults were experienced and satisfactory results were obtained in all cases
  265.   Ranjbar, A.M., Shirani, A.R., Fathi, A.F., 1992. A New Approach for Fault Location Problem on Power-Lines. Ieee Transactions on Power Delivery 7, 146-151.
Abstract: There have been many techniques presented for finding the exact location of faults on transmission lines. In most of these approaches, fault locations have been detected through the use of lumped models. Since these models do not represent the capacitance of the transmission lines, significant errors are generally encountered in exact location of faults. This paper suggests a new technique based upon the distributed model of transmission lines to overcome the problems encountered in traditional approaches. This approach considers the effect of capacitance explicitly and therefore enables the detection of faults in transmission lines more precisely
  266.   Popovic, L.M., 1991. Analytical Expressions for Evaluating Screening Effect of Transmission-Line Earth Wire. Iee Proceedings-C Generation Transmission and Distribution 138, 289-296.
Abstract: When an unbalanced fault occurs, the fault current in the transmission lines induces an electromotive force in nearby parallel telecommunication circuits, as well as in different metal pipelines. The existence of a earth wire in these cases exerts a favourable influence known as the 'screening effect' which is considered in the calculation of the induced electromotive force through the screening factor. An original procedure for obtaining relatively simple analytical expressions for determining the screening factors is presented. The procedure incorporates the fact that the earth wire is galvanically connected to the structures along the line and, at the terminals of the line, to the station frame. The procedure is based on Kirchoff's equations, the principle of super-position and the summing of geometrical series
  267.   Englert, T.J., Chowdhury, B.H., Grigsby, E., 1991. A Laboratory Investigation of Electrooptic Kerr Effect for Detection of Electric Transmission-Line Faults. Ieee Transactions on Power Delivery 6, 979-985.
Abstract: A prototype Kerr cell has been constructed and tested for detecting and identifying faults by monitoring high voltages such as are found in electric power delivery systems. Simulated faults have been generated under laboratory conditions, monitored by the Kerr cell, and preliminary analysis done using analog-to-digital conversion of the detected waveforms with a single board microprocessor serially interfaced with a personal computer. The occurrence of faults is readily observed and results indicate that identification of fault types can be accomplished within less than one cycle of a standard sixty-cycle-per-second delivery system such as that found in the United States. With a dedicated analysis system such a technique may prove timely and economical in fault identification and location
  268.   Johns, A.T., Jamali, S., 1990. Accurate Fault Location Technique for Power Transmission-Lines. Iee Proceedings-C Generation Transmission and Distribution 137, 395-402.

4 comments:

  1. how could i get journal in PDF format??
    Please help m doing M.tech project on HVDC protection,.....

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  2. oke thanks . i help you looking for On HVDC Protection ( Abstrac) , using reference manager 12

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  3. Congratulations! This is the great things. Thanks to giving the time to share such a nice information.
    Kimmer Trans

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  4. hi.. may i know the fault location method being implemented at power transmission line in Indoenesia?
    thanks :)

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