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
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
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. 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
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
4. Pang, C.Z., Kezunovic, M., 2010. Fast Distance Relay Scheme for Detecting Symmetrical Fault During Power Swing. Ieee Transactions on Power Delivery 25, 2205-2212.
Abstract: The power swing caused by various disturbances will affect distance relay behavior and may result in relay misoperation. This paper provides a fast detection scheme for symmetrical fault during power swing for distance relay, which is based on extracting the high-frequency component energy of forward and backward traveling waves induced by faults. The multiresolution analysis based on wavelet transform has the ability to decompose the analyzed signals into different frequency bands. The selection of mother wavelet and the number of levels of wavelet transform are carefully studied. The fault can be identified by feature extracting from the d1 component of Daubechies-8 (Db8) wavelet transform. The proposed approach is verified by using the IEEE reference model implemented by using the Alternate Transients Program and the test results have been presented in this paper. This proposed method can be used for distance relay operation blocking or monitoring
Abstract: The power swing caused by various disturbances will affect distance relay behavior and may result in relay misoperation. This paper provides a fast detection scheme for symmetrical fault during power swing for distance relay, which is based on extracting the high-frequency component energy of forward and backward traveling waves induced by faults. The multiresolution analysis based on wavelet transform has the ability to decompose the analyzed signals into different frequency bands. The selection of mother wavelet and the number of levels of wavelet transform are carefully studied. The fault can be identified by feature extracting from the d1 component of Daubechies-8 (Db8) wavelet transform. The proposed approach is verified by using the IEEE reference model implemented by using the Alternate Transients Program and the test results have been presented in this paper. This proposed method can be used for distance relay operation blocking or monitoring
5. 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
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
6. 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
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
7. 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
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
8. 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
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
9. Zhao, Y., Zhang, Z.X., Zhao, Y.B., Gao, H.J., 2010. Fault detection with network communication. International Journal of Systems Science 41, 947-956.
Abstract: This article investigates the problem of fault detection for continuous time systems with network communication links. A network communication channel is assumed to be existing between the plant and the fault detection filter, and three types of incomplete measurements which typically appear in a network environment are simultaneously addressed, including measurement quantisation effect, signal transmission delay and data packet dropout. A mathematical model is presented to account for those issues in a unified form. Based on that, a full-order fault detection filter is designed such that the residual system is asymptotically stable and preserves a guaranteed performance. A sufficient condition of the existence of the fault detection filter is obtained and all the results are formulated in the form of linear matrix inequalities, which can be readily solved via standard numerical software. Finally, a simulation example is provided to illustrate the usefulness of the developed theoretical results
Abstract: This article investigates the problem of fault detection for continuous time systems with network communication links. A network communication channel is assumed to be existing between the plant and the fault detection filter, and three types of incomplete measurements which typically appear in a network environment are simultaneously addressed, including measurement quantisation effect, signal transmission delay and data packet dropout. A mathematical model is presented to account for those issues in a unified form. Based on that, a full-order fault detection filter is designed such that the residual system is asymptotically stable and preserves a guaranteed performance. A sufficient condition of the existence of the fault detection filter is obtained and all the results are formulated in the form of linear matrix inequalities, which can be readily solved via standard numerical software. Finally, a simulation example is provided to illustrate the usefulness of the developed theoretical results
10. 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
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
11. Babczynski, T., Lukowicz, M., Magott, J., 2010. Time Coordination of Distance Protections Using Probabilistic Fault Trees With Time Dependencies. Ieee Transactions on Power Delivery 25, 1402-1409.
Abstract: Distance protection of the electrical power system is analyzed in the paper. Electrical power transmission lines are divided into sections equipped with protective relaying system. Numerical protection relays use specialized digital signal processors as the computational hardware, together with the associated software tools. The input analogue signals are converted into a digital representation and processed according to the appropriate mathematical algorithms. The distance protection is based on local and remote relays. Hazard is the event: remote circuit breaker tripping provided the local circuit breaker can be opened. Coordination of operation of protection relays in time domain is an important and difficult problem. Incorrect values of time delays of protective relays can cause the hazard. In the paper, the time settings are performed using probabilistic fault trees with time dependencies (PFTTD). PFTTD is built for the above mentioned hazard. PFTTD are used in selection of time delays of primary (local) and backup (remote) protections. Results of computations of hazard probabilities as a function of time delay are given
Abstract: Distance protection of the electrical power system is analyzed in the paper. Electrical power transmission lines are divided into sections equipped with protective relaying system. Numerical protection relays use specialized digital signal processors as the computational hardware, together with the associated software tools. The input analogue signals are converted into a digital representation and processed according to the appropriate mathematical algorithms. The distance protection is based on local and remote relays. Hazard is the event: remote circuit breaker tripping provided the local circuit breaker can be opened. Coordination of operation of protection relays in time domain is an important and difficult problem. Incorrect values of time delays of protective relays can cause the hazard. In the paper, the time settings are performed using probabilistic fault trees with time dependencies (PFTTD). PFTTD is built for the above mentioned hazard. PFTTD are used in selection of time delays of primary (local) and backup (remote) protections. Results of computations of hazard probabilities as a function of time delay are given
12. Ibrahim, D.K., Eldin, E.S.T., Aboul-Zahab, E.M., Saleh, S.M., 2010. Real time evaluation of DWT-based high impedance fault detection in EHV transmission. Electric Power Systems Research 80, 907-914.
Abstract: It is possible to capture the required travelling wave information contained in fault transients using wavelet transform This paper presents practical real time testing for the high impedance fault (HIF) detection algorithm based on real time accidents data The proposed scheme is implemented for HIF detection in extra high voltage transmission lines The classifier is based on an algorithm that uses recursive method to sum the absolute values of the high frequency signal generated over one cycle and shifting one sample. Characteristics of this scheme are analyzed by extensive real time studies that clearly reveal that this technique can accurately detect HIFs in the EHV transmission lines within only half a cycle from the instant of fault occurrence The reliability of this scheme is not affected by different fault conditions such as fault distance and fault inception angle. (C) 2010 Elsevier B V All tights reserved
Abstract: It is possible to capture the required travelling wave information contained in fault transients using wavelet transform This paper presents practical real time testing for the high impedance fault (HIF) detection algorithm based on real time accidents data The proposed scheme is implemented for HIF detection in extra high voltage transmission lines The classifier is based on an algorithm that uses recursive method to sum the absolute values of the high frequency signal generated over one cycle and shifting one sample. Characteristics of this scheme are analyzed by extensive real time studies that clearly reveal that this technique can accurately detect HIFs in the EHV transmission lines within only half a cycle from the instant of fault occurrence The reliability of this scheme is not affected by different fault conditions such as fault distance and fault inception angle. (C) 2010 Elsevier B V All tights reserved
13. 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
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
14. 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
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
17. Benigni, A., D'Antona, G., Ghisla, U., Monti, A., Ponci, F., 2010. A Decentralized Observer for Ship Power System Applications: Implementation and Experimental Validation. Ieee Transactions on Instrumentation and Measurement 59, 440-449.
Abstract: In the last few years, the growing complexity of the electrical power networks, mainly due to the increased use of electronic converters together with the requirements of a higher level of reliability and security, pushed the development of new techniques for the state estimation of the power systems. In this paper, the authors focus their attention on the implementation and experimental validation of a decentralized observer for the state estimation in an electric ship, whose power network is characterized by fast dynamics and by the presence of many electronic devices. The proposed solution implements a decentralized information filter (DIF)
Abstract: In the last few years, the growing complexity of the electrical power networks, mainly due to the increased use of electronic converters together with the requirements of a higher level of reliability and security, pushed the development of new techniques for the state estimation of the power systems. In this paper, the authors focus their attention on the implementation and experimental validation of a decentralized observer for the state estimation in an electric ship, whose power network is characterized by fast dynamics and by the presence of many electronic devices. The proposed solution implements a decentralized information filter (DIF)
20. Ramtharan, G., Arulampalam, A., Ekanayake, J.B., Hughes, F.M., Jenkins, N., 2009. Fault ride through of fully rated converter wind turbines with AC and DC transmission systems. Iet Renewable Power Generation 3, 426-438.
Abstract: Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex communication requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities
Abstract: Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex communication requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities
22. 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
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
23. 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)
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)
24. Kia, S.H., Henao, H., Capolino, G.A., 2009. Torsional Vibration Effects on Induction Machine Current and Torque Signatures in Gearbox-Based Electromechanical System. Ieee Transactions on Industrial Electronics 56, 4689-4699.
Abstract: The monitoring of heavy-duty electromechanical systems is crucial for their preventive maintenance planning. In these systems, the mechanical anomalies such as load troubles, great torque dynamic variations, and torsional oscillations lead to shaft fatigue and aging of other mechanical parts such as bearings and gearboxes. In this paper, a gearbox-based electromechanical system is investigated. Initially, a simple gearbox dynamic model is used to show the effects of rotating input, output, and mesh frequency components on the electromagnetic torque and consequently on the stator current signature. By this model, the influence of transmission error, eccentricities of pinion/wheel, and teeth contact stiffness variation is demonstrated for a healthy gearbox. Then, it is shown that the electrical machine can be considered as a torque sensor through electromagnetic torque estimation for torsional vibration monitoring without any extra mechanical sensor. A test-rig based on a 5.5-kW three-phase squirrel-cage induction motor connected to a wound-rotor 4-kW induction generator via a one-stage gearbox has been used to validate the proposed method
Abstract: The monitoring of heavy-duty electromechanical systems is crucial for their preventive maintenance planning. In these systems, the mechanical anomalies such as load troubles, great torque dynamic variations, and torsional oscillations lead to shaft fatigue and aging of other mechanical parts such as bearings and gearboxes. In this paper, a gearbox-based electromechanical system is investigated. Initially, a simple gearbox dynamic model is used to show the effects of rotating input, output, and mesh frequency components on the electromagnetic torque and consequently on the stator current signature. By this model, the influence of transmission error, eccentricities of pinion/wheel, and teeth contact stiffness variation is demonstrated for a healthy gearbox. Then, it is shown that the electrical machine can be considered as a torque sensor through electromagnetic torque estimation for torsional vibration monitoring without any extra mechanical sensor. A test-rig based on a 5.5-kW three-phase squirrel-cage induction motor connected to a wound-rotor 4-kW induction generator via a one-stage gearbox has been used to validate the proposed method
25. 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
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
27. Valsan, S.P., Swarup, K.S., 2009. Wavelet transform based digital protection for transmission lines. International Journal of Electrical Power & Energy Systems 31, 379-388.
Abstract: This paper presents a high speed, computationally efficient scheme for protection of transmission lines. The relay logic consists of three parts: directional protection, fault classification and fault location. Wavelet transform is used for extracting information from the fault transients and only the first level high frequency details of the voltages and currents are used. Proposed protection logic compares the directional signals from both terminals to discriminate between faults inside and outside the zone of interest. Fault classification is achieved using local terminal current information. An estimate of the location of the faults is obtained utilizing single faulted phase current information from both terminals. The logic is deterministic and can work reliably in the presence of fault resistance, load variation and CT saturation. The validity of the proposed logic was exhaustively tested by simulating various types of faults on a four bus meshed system modeled in EMTP/ATP. (C) 2009 Elsevier Ltd. All rights reserved
Abstract: This paper presents a high speed, computationally efficient scheme for protection of transmission lines. The relay logic consists of three parts: directional protection, fault classification and fault location. Wavelet transform is used for extracting information from the fault transients and only the first level high frequency details of the voltages and currents are used. Proposed protection logic compares the directional signals from both terminals to discriminate between faults inside and outside the zone of interest. Fault classification is achieved using local terminal current information. An estimate of the location of the faults is obtained utilizing single faulted phase current information from both terminals. The logic is deterministic and can work reliably in the presence of fault resistance, load variation and CT saturation. The validity of the proposed logic was exhaustively tested by simulating various types of faults on a four bus meshed system modeled in EMTP/ATP. (C) 2009 Elsevier Ltd. All rights reserved
29. Rigatos, G., Siano, P., Piccolo, A., 2009. Neural network-based approach for early detection of cascading events in electric power systems. Iet Generation Transmission & Distribution 3, 650-665.
Abstract: This study proposes neural modelling and fault diagnosis methods for the early detection of cascading events in electric power systems. A neural-fuzzy network is used to model the dynamics of the power transmission system in fault-free conditions. The output of the neural-fuzzy network is compared to measurements from the power system and the obtained residuals undergo statistical processing according to a fault detection and isolation algorithm. If a fault threshold, defined by the fault detection and isolation (FDI) algorithm, is exceeded then deviation from normal operation can be detected at its early stages and an alarm can be launched. In several cases fault isolation can be also performed, that is the sources of fault in the power transmission system can be also identified. The performance of the proposed methodology is tested through simulation experiments
Abstract: This study proposes neural modelling and fault diagnosis methods for the early detection of cascading events in electric power systems. A neural-fuzzy network is used to model the dynamics of the power transmission system in fault-free conditions. The output of the neural-fuzzy network is compared to measurements from the power system and the obtained residuals undergo statistical processing according to a fault detection and isolation algorithm. If a fault threshold, defined by the fault detection and isolation (FDI) algorithm, is exceeded then deviation from normal operation can be detected at its early stages and an alarm can be launched. In several cases fault isolation can be also performed, that is the sources of fault in the power transmission system can be also identified. The performance of the proposed methodology is tested through simulation experiments
30. Adami, J.F., Silveira, P.M., Martinez, M.L.B., Perez, R.C., Dallbello, A.C., 2009. New Approach to Improve High-Voltage Transmission Line Reliability. Ieee Transactions on Power Delivery 24, 1515-1520.
Abstract: This paper presents a remote fault detection and identification system for transmission lines, permitting elimination, or at least minimizing, the use of maintenance methods employed by power utilities, as a result of its technical potential and capability to reduce operational costs. It consists of a data acquisition system, capable of acquiring and storing high frequency signals present in the transmission lines (TLs). The signals, after their storage, are treated and identified through signal processing techniques such as digital filters and neural networks. This system has been installed in the reception terminal of one power line carrier system, in an electric power utility in Brazil. Many fault-simulating tests were carried out in the transmission line for pattern definition. Therefore, it is possible to develop an algorithm capable of identifying any potential transmission line fault. With the results obtained in this first part of the research, and with the continuity of the project, new signals will be obtained, identified and trained by the neural network
Abstract: This paper presents a remote fault detection and identification system for transmission lines, permitting elimination, or at least minimizing, the use of maintenance methods employed by power utilities, as a result of its technical potential and capability to reduce operational costs. It consists of a data acquisition system, capable of acquiring and storing high frequency signals present in the transmission lines (TLs). The signals, after their storage, are treated and identified through signal processing techniques such as digital filters and neural networks. This system has been installed in the reception terminal of one power line carrier system, in an electric power utility in Brazil. Many fault-simulating tests were carried out in the transmission line for pattern definition. Therefore, it is possible to develop an algorithm capable of identifying any potential transmission line fault. With the results obtained in this first part of the research, and with the continuity of the project, new signals will be obtained, identified and trained by the neural network
31. Valsan, S.P., Swarup, K.S., 2009. High-Speed Fault Classification in Power Lines: Theory and FPGA-Based Implementation. Ieee Transactions on Industrial Electronics 56, 1793-1800.
Abstract: This paper presents a fast hardware-efficient logic for fault detection and classification in transmission lines, implemented using a field-programmable gate array (FPGA). The general-purpose SPARTA3E FPGA was employed for developing the prototype, with all the coding done using a hardware description language (HDL) called very high speed integrated circuit (VHDL). The proposed logic employs only one-terminal current samples and is based on wavelet analysis. Depending on the amount of high frequency components in the current signals after processing the faults are classified into ten types. The Real Time Windows Target Toolbox of MATLAB was used to apply the current signal inputs to the prototype in real time. An adaptive threshold value is chosen, rather than a fixed threshold in the case of faults involving the ground, to make the classification reliable and accurate. The fault classification time is 6 ms, which is about 113 of the power frequency cycle (20 ms). A high level of computational efficiency is achieved as compared to the other wavelet-transform-based algorithms, since only the high frequency details at first level are employed in this algorithm. The validity of the proposed logic was exhaustively tested by simulating various types of faults on a system modeled in the Electromagnetic Transients Program/Alternative Transients Program. The proposed logic was found to be highly reliable and accurate, even in the presence of fault resistance
Abstract: This paper presents a fast hardware-efficient logic for fault detection and classification in transmission lines, implemented using a field-programmable gate array (FPGA). The general-purpose SPARTA3E FPGA was employed for developing the prototype, with all the coding done using a hardware description language (HDL) called very high speed integrated circuit (VHDL). The proposed logic employs only one-terminal current samples and is based on wavelet analysis. Depending on the amount of high frequency components in the current signals after processing the faults are classified into ten types. The Real Time Windows Target Toolbox of MATLAB was used to apply the current signal inputs to the prototype in real time. An adaptive threshold value is chosen, rather than a fixed threshold in the case of faults involving the ground, to make the classification reliable and accurate. The fault classification time is 6 ms, which is about 113 of the power frequency cycle (20 ms). A high level of computational efficiency is achieved as compared to the other wavelet-transform-based algorithms, since only the high frequency details at first level are employed in this algorithm. The validity of the proposed logic was exhaustively tested by simulating various types of faults on a system modeled in the Electromagnetic Transients Program/Alternative Transients Program. The proposed logic was found to be highly reliable and accurate, even in the presence of fault resistance
32. Pai, H.T., Sung, J.T., 2009. Equal-Gain Combination for adaptive distributed classification in Wireless Sensor Networks. International Journal of Ad Hoc and Ubiquitous Computing 4, 115-121.
Abstract: A fault-tolerant classification system in Wireless Sensor Networks (WSNs) has recently been proposed. An adaptive redetection algorithm and an adaptive retransmission scheme were later developed to reduce the misclassification probability of the system when observations of sensors is highly noisy, and the transmission channel between the sensor and the fusion centre of the network is deeply faded, respectively. The observation and the received data are discarded if they are unreliable. However, they still have useful information. This work applies Equal-Gain Combination (EGC) techniques to utilise the unreliable data. Simulation results show that the new adaptive method with EGC outperforms the original one
Abstract: A fault-tolerant classification system in Wireless Sensor Networks (WSNs) has recently been proposed. An adaptive redetection algorithm and an adaptive retransmission scheme were later developed to reduce the misclassification probability of the system when observations of sensors is highly noisy, and the transmission channel between the sensor and the fusion centre of the network is deeply faded, respectively. The observation and the received data are discarded if they are unreliable. However, they still have useful information. This work applies Equal-Gain Combination (EGC) techniques to utilise the unreliable data. Simulation results show that the new adaptive method with EGC outperforms the original one
33. 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
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
34. Hernandez-Orallo, E., Vila-Carbo, J., 2009. A proactive backup scheme for reliable real-time transmission. Journal of Parallel and Distributed Computing 69, 482-490.
Abstract: Reliable transmission is a key issue for distributed real-time applications. The concept of Real-time Dependable Channel was introduced to provide availability to real-time transmission. Two aspects are important for the efficiency of a Real-time dependable channel: assuring the end-to-end delay bound and optimising the utilisation of network resources. A packet can miss its delay bound for two reasons: network congestion or network failure. The classic solution to this problem has been the use of Backup Channels which introduces the notion of availability at the expense of increasing the use of network resources. However, this over-provisioning of resources is potentially wasted, since the failure rate is very low. This paper introduces a new failure detection scheme for Real-time Transmission, which is called Proactive Backup Channel. This scheme is based on activating the backup channel before a network failure or congestion is produced. This way, the failure recovery time is reduced, and, as proven in the paper, the use of network resources is minimized. (C) 2009 Elsevier Inc. All rights reserved
Abstract: Reliable transmission is a key issue for distributed real-time applications. The concept of Real-time Dependable Channel was introduced to provide availability to real-time transmission. Two aspects are important for the efficiency of a Real-time dependable channel: assuring the end-to-end delay bound and optimising the utilisation of network resources. A packet can miss its delay bound for two reasons: network congestion or network failure. The classic solution to this problem has been the use of Backup Channels which introduces the notion of availability at the expense of increasing the use of network resources. However, this over-provisioning of resources is potentially wasted, since the failure rate is very low. This paper introduces a new failure detection scheme for Real-time Transmission, which is called Proactive Backup Channel. This scheme is based on activating the backup channel before a network failure or congestion is produced. This way, the failure recovery time is reduced, and, as proven in the paper, the use of network resources is minimized. (C) 2009 Elsevier Inc. All rights reserved
35. Armeni, S., Casavola, A., Mosca, E., 2009. Robust fault detection and isolation for LPV systems under a sensitivity constraint. International Journal of Adaptive Control and Signal Processing 23, 55-72.
Abstract: A novel fault, detection and isolation (FDI) filter design method is proposed for linear parameter varying (LPV) systems. The LPV system description can be Used to approximate the behavior of nonlinear systems and leads to simple nonlinear FDI designs. The main goal here is to obtain residual generator (RG) filters with enhanced fault transmission dc-gains and large H-infinity nuisance attenuation. This is achieved using bilinear matrix inequality techniques by exploiting the relevant geometrical properties of the affine LPV description. Finally, it is shown by a nonlinear example that the RG filters designed by the proposed method compare well with alternative approaches including direct nonlinear design methods. Copyright (C) 2008 John Wiley & Sons, Ltd
Abstract: A novel fault, detection and isolation (FDI) filter design method is proposed for linear parameter varying (LPV) systems. The LPV system description can be Used to approximate the behavior of nonlinear systems and leads to simple nonlinear FDI designs. The main goal here is to obtain residual generator (RG) filters with enhanced fault transmission dc-gains and large H-infinity nuisance attenuation. This is achieved using bilinear matrix inequality techniques by exploiting the relevant geometrical properties of the affine LPV description. Finally, it is shown by a nonlinear example that the RG filters designed by the proposed method compare well with alternative approaches including direct nonlinear design methods. Copyright (C) 2008 John Wiley & Sons, Ltd
36. Liao, Y., Kezunovic, M., 2009. Online Optimal Transmission Line Parameter Estimation for Relaying Applications. Ieee Transactions on Power Delivery 24, 96-102.
Abstract: Transmission line protective relaying algorithms usually require transmission line parameters as inputs and thus accuracy of line parameters plays a pivotal role in ensuring the reliable performance of relaying algorithms. Online estimation of line parameters is highly desirable and various methods have been proposed in the past. These methods perform well when the measurements utilized are accurate; they may yield erroneous results when the measurements contain considerable, errors. Based on nonlinear optimal estimation theory, this paper puts forward an optimal estimator for deriving the positive sequence line parameters, capable of detecting and identifying the bad measurement data, minimizing the impacts of the measurement errors and thus significantly improving the estimation accuracy. The solution is based on the distributed parameter line model and thus fully considers the effects of shunt capacitances of the line. Case studies based on simulated data are presented for demonstrating the effectiveness of the new approach
Abstract: Transmission line protective relaying algorithms usually require transmission line parameters as inputs and thus accuracy of line parameters plays a pivotal role in ensuring the reliable performance of relaying algorithms. Online estimation of line parameters is highly desirable and various methods have been proposed in the past. These methods perform well when the measurements utilized are accurate; they may yield erroneous results when the measurements contain considerable, errors. Based on nonlinear optimal estimation theory, this paper puts forward an optimal estimator for deriving the positive sequence line parameters, capable of detecting and identifying the bad measurement data, minimizing the impacts of the measurement errors and thus significantly improving the estimation accuracy. The solution is based on the distributed parameter line model and thus fully considers the effects of shunt capacitances of the line. Case studies based on simulated data are presented for demonstrating the effectiveness of the new approach
37. 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
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
40. Parikh, U.B., Das, B., Maheshwari, R.P., 2008. Combined wavelet-SVM technique for fault zone detection in a series compensated transmission line. Ieee Transactions on Power Delivery 23, 1789-1794.
Abstract: This paper presents a combined wavelet-support vector machine (SVM) technique for fault zone identification in a series compensated transmission line. The proposed metho uses the samples of three line currents for one cycle duration to accomplish this task. Initially, the features of the line currents are extracted by first level decomposition of the current samples using discrete wavelet transform (DWT). Subsequently, the extracted features are applied as inputs to a SVM for determining the fault zone (whether the fault is before or after the series capacitor, a observed from the relay point). The feasibility of the propose algorithm has been tested on a 300-km, 400-kV series compensate transmission line for all the ten types of faults through detailed digital simulation using PSCAD/EMTDC. Upon testing on more than 25 000 fault cases with varying fault resistance, fault inception angle, prefault power transfer level, percentage compensation level, and source impedances, the performance of the developed method has been found to be quite promising
Abstract: This paper presents a combined wavelet-support vector machine (SVM) technique for fault zone identification in a series compensated transmission line. The proposed metho uses the samples of three line currents for one cycle duration to accomplish this task. Initially, the features of the line currents are extracted by first level decomposition of the current samples using discrete wavelet transform (DWT). Subsequently, the extracted features are applied as inputs to a SVM for determining the fault zone (whether the fault is before or after the series capacitor, a observed from the relay point). The feasibility of the propose algorithm has been tested on a 300-km, 400-kV series compensate transmission line for all the ten types of faults through detailed digital simulation using PSCAD/EMTDC. Upon testing on more than 25 000 fault cases with varying fault resistance, fault inception angle, prefault power transfer level, percentage compensation level, and source impedances, the performance of the developed method has been found to be quite promising
41. Salim, R.H., de Oliveira, K.R.C., Filomena, A.D., Resener, M., Bretas, A.S., 2008. Hybrid fault diagnosis scheme implementation for power distribution systems automation. Ieee Transactions on Power Delivery 23, 1846-1856.
Abstract: Power distribution automation and control are import-ant tools in the current restructured electricity markets. Unfortunately, due to its stochastic nature, distribution systems faults are hardly avoidable. This paper proposes a novel fault diagnosis scheme for power distribution systems, composed by three different processes: fault detection and classification, fault location, and fault section determination. The fault detection and classification technique is wavelet based. The fault-location technique is impedance based and uses local voltage and current fundamental phasors. The fault section determination method is artificial neural network based and uses the local current and voltage signals to estimate the faulted section. The proposed hybrid scheme was validated through Alternate Transient Program/Electromagentic Transients Program simulations and was implemented as embedded software. It is currently used as a fault diagnosis tool in a Southern Brazilian power distribution company
Abstract: Power distribution automation and control are import-ant tools in the current restructured electricity markets. Unfortunately, due to its stochastic nature, distribution systems faults are hardly avoidable. This paper proposes a novel fault diagnosis scheme for power distribution systems, composed by three different processes: fault detection and classification, fault location, and fault section determination. The fault detection and classification technique is wavelet based. The fault-location technique is impedance based and uses local voltage and current fundamental phasors. The fault section determination method is artificial neural network based and uses the local current and voltage signals to estimate the faulted section. The proposed hybrid scheme was validated through Alternate Transient Program/Electromagentic Transients Program simulations and was implemented as embedded software. It is currently used as a fault diagnosis tool in a Southern Brazilian power distribution company
42. 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
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
43. Wang, B.C., Fujinaka, T., Omatu, S., Abe, T., 2008. Automatic inspection of transmission devices using acoustic data. Ieee Transactions on Automation Science and Engineering 5, 361-367.
Abstract: Most factories depend on skilled workers to test the quality of transmission devices by listening to the sound. In this paper, an intelligent inspection system is proposed to evaluate the quality of transmission devices in place of experts. Since the causes of faults of transmission devices are complex and a defective product might simultaneously have many types of faults, the discrimination process between defective and nondefective products and the classification process of defective products are treated separately in the proposed system. From the acoustic data of operating transmission devices, we extract the feature vectors based on time-frequency analysis and train a neuroclassifier by using the learning vector quantization (LVQ). Furthermore, the genetic algorithm (GA) with floating point (FP) is utilized to select some significant frequencies from the spectra of acoustic data of defective and nondefective products and to make a quality evaluation rule automatically. The defective products are picked up from the automatic production line according to the evaluation rule and the trained neuroclassifier. At last, the self-organizing feature map (SOM) algorithm is used to identify the kinds of defective products. The experimental results show that the proposed intelligent system is able to perform the quality evaluation of transmission devices successfully. Note to Practitioners-This paper was motivated by the problem of developing an intelligent evaluation system in place of skilled workers to evaluate the quality of transmission devices automatically based on acoustic data. Most of the prior works in quality evaluation of transmission devices are based on processing vibrometer signals for system vibrations. Such vibrometers; must be installed on the surface of vibrating part of transmission devices, which alter the physical integrity. In this paper, the acoustic data of operating transmission devices are recorded. We first compute the ASFTS and FVAVT, where ASFTS denotes the average of a serial of spectra calculated from time segments of an acoustic data and FVAVT denotes the feature vector of amplitude variation with time in a certain band. By using the different characteristics of the ASFTS and the FVAVT, we apply the LVQ and the FGA to the quality evaluation of transmission devices, respectively. Utilizing the advantages of the SOM, we classify the defective products successfully. In the industry production, the quality of each batch of products will change according to the situation of equipments. Similarly, the quality evaluation rule will be adjusted according to the yield and the request of customers. The proposed system can evaluate the quality of transmission devices correctly as demanded so long as we change the nondefective and defective samples
Abstract: Most factories depend on skilled workers to test the quality of transmission devices by listening to the sound. In this paper, an intelligent inspection system is proposed to evaluate the quality of transmission devices in place of experts. Since the causes of faults of transmission devices are complex and a defective product might simultaneously have many types of faults, the discrimination process between defective and nondefective products and the classification process of defective products are treated separately in the proposed system. From the acoustic data of operating transmission devices, we extract the feature vectors based on time-frequency analysis and train a neuroclassifier by using the learning vector quantization (LVQ). Furthermore, the genetic algorithm (GA) with floating point (FP) is utilized to select some significant frequencies from the spectra of acoustic data of defective and nondefective products and to make a quality evaluation rule automatically. The defective products are picked up from the automatic production line according to the evaluation rule and the trained neuroclassifier. At last, the self-organizing feature map (SOM) algorithm is used to identify the kinds of defective products. The experimental results show that the proposed intelligent system is able to perform the quality evaluation of transmission devices successfully. Note to Practitioners-This paper was motivated by the problem of developing an intelligent evaluation system in place of skilled workers to evaluate the quality of transmission devices automatically based on acoustic data. Most of the prior works in quality evaluation of transmission devices are based on processing vibrometer signals for system vibrations. Such vibrometers; must be installed on the surface of vibrating part of transmission devices, which alter the physical integrity. In this paper, the acoustic data of operating transmission devices are recorded. We first compute the ASFTS and FVAVT, where ASFTS denotes the average of a serial of spectra calculated from time segments of an acoustic data and FVAVT denotes the feature vector of amplitude variation with time in a certain band. By using the different characteristics of the ASFTS and the FVAVT, we apply the LVQ and the FGA to the quality evaluation of transmission devices, respectively. Utilizing the advantages of the SOM, we classify the defective products successfully. In the industry production, the quality of each batch of products will change according to the situation of equipments. Similarly, the quality evaluation rule will be adjusted according to the yield and the request of customers. The proposed system can evaluate the quality of transmission devices correctly as demanded so long as we change the nondefective and defective samples
45. Firpi, H., Vachtsevanos, G., 2008. Genetically programmed-based artificial features extraction applied to fault detection. Engineering Applications of Artificial Intelligence 21, 558-568.
Abstract: This paper presents a novel application of genetically programmed artificial features, which are computer crafted, data driven, and possibly without physical interpretation, to the problem of fault detection. Artificial features are extracted from vibration data of an accelerometer sensor to monitor and detect a crack fault or incipient failure seeded in an intermediate gearbox of a helicopter's main transmission. Classification accuracies for the artificial feature constructed from raw data exceeded 99% over training and independent validation sets. As a benchmark, GP-based artificial features constructed from conventional ones underperformed those derived from raw data by over 2% over the training and over 11% over the testing data. (c) 2007 Elsevier Ltd. All rights reserved
Abstract: This paper presents a novel application of genetically programmed artificial features, which are computer crafted, data driven, and possibly without physical interpretation, to the problem of fault detection. Artificial features are extracted from vibration data of an accelerometer sensor to monitor and detect a crack fault or incipient failure seeded in an intermediate gearbox of a helicopter's main transmission. Classification accuracies for the artificial feature constructed from raw data exceeded 99% over training and independent validation sets. As a benchmark, GP-based artificial features constructed from conventional ones underperformed those derived from raw data by over 2% over the training and over 11% over the testing data. (c) 2007 Elsevier Ltd. All rights reserved
46. Rezaei, N., Haghifam, M.R., 2008. Protection scheme for a distribution system with distributed generation using neural networks. International Journal of Electrical Power & Energy Systems 30, 235-241.
Abstract: Interconnection of distributed generation (DG) to a radial distribution system has some impacts on the coordination of protection devices. In this case, faults are fed by multi-sources; networks and DGs. Existence of multi-sources in fault condition is the main difficulty in the identification and location of faults and therefore distribution system protection. New protection methods should be introduced for isolation of faulted sections. This paper presents a novel approach that can overcome the above problems. A feed forward neural network is used to identify the fault location. The predicted results from the algorithm prove the effectiveness of the proposed procedure for identifying fault location and then protection of the system for a wide range of system conditions. (c) 2007 Elsevier Ltd. All rights reserved
Abstract: Interconnection of distributed generation (DG) to a radial distribution system has some impacts on the coordination of protection devices. In this case, faults are fed by multi-sources; networks and DGs. Existence of multi-sources in fault condition is the main difficulty in the identification and location of faults and therefore distribution system protection. New protection methods should be introduced for isolation of faulted sections. This paper presents a novel approach that can overcome the above problems. A feed forward neural network is used to identify the fault location. The predicted results from the algorithm prove the effectiveness of the proposed procedure for identifying fault location and then protection of the system for a wide range of system conditions. (c) 2007 Elsevier Ltd. All rights reserved
47. Li, W., Zhang, P., Ding, S.X., Chihaia, L.C., Goldschmidt, E., Bredtmann, O., Czylwik, A., 2008. Networked fault detection systems with noisy data transmission. At-Automatisierungstechnik 56, 49-57.
Abstract: In this paper, a networked observer-based fault detection (FD) system is presented. First, the influence of noisy data transmission on the FD performance is analyzed and modeled. Based on it, a design scheme is developed for the construction of observer and residual evaluation unit. The core of this scheme is the integrated design of the coding strategy and FD system. The resulting FD system ensures high fault detectability and low false alarm rate
Abstract: In this paper, a networked observer-based fault detection (FD) system is presented. First, the influence of noisy data transmission on the FD performance is analyzed and modeled. Based on it, a design scheme is developed for the construction of observer and residual evaluation unit. The core of this scheme is the integrated design of the coding strategy and FD system. The resulting FD system ensures high fault detectability and low false alarm rate
48. Samantaray, S.R., Dash, P.K., 2008. Transmission line distance relaying using a variable window short-time Fourier transform. Electric Power Systems Research 78, 595-604.
Abstract: This paper presents a new approach for transmission line protection using a variable window short-time Fourier transform known as S-transform. The S-transform (ST) is a time-frequency spectral localization method, similar to short-time Fourier transform (STFT), but with a Gaussian window whose width scales inversely, and whose height scales linearly with the frequency. The change in spectral energy of the ST of the current and voltage signals provide the information regarding fault detection. After the fault detection, the impedance to the fault point is calculated using the estimated phasors of the faulted current and voltage signals which provide accurate results even with noisy conditions. Also, the fault location is calculated using polynomial curve fitting technique with a devised index obtained from the ratio of spectral energy of the voltage and current signals, respectively. (C) 2007 Elsevier B.V. All rights reserved
Abstract: This paper presents a new approach for transmission line protection using a variable window short-time Fourier transform known as S-transform. The S-transform (ST) is a time-frequency spectral localization method, similar to short-time Fourier transform (STFT), but with a Gaussian window whose width scales inversely, and whose height scales linearly with the frequency. The change in spectral energy of the ST of the current and voltage signals provide the information regarding fault detection. After the fault detection, the impedance to the fault point is calculated using the estimated phasors of the faulted current and voltage signals which provide accurate results even with noisy conditions. Also, the fault location is calculated using polynomial curve fitting technique with a devised index obtained from the ratio of spectral energy of the voltage and current signals, respectively. (C) 2007 Elsevier B.V. All rights reserved
49. Ozgonenel, O., Kilic, E., 2008. Modeling and real-time fault identification in transformers. Journal of the Franklin Institute-Engineering and Applied Mathematics 345, 205-225.
Abstract: In this paper, a different internal fault modeling and an identification algorithm are presented. There has been an increasing concern about turn-to-turn faults in transformers because of the high costs of unexpected outages. It is not always possible to analyze the transformer behavior under such faults at rated conditions, since the tests are highly destructive. To develop transformer internal fault detection technique, a transformer model to simulate internal faults is required. This paper describes a novel technique and methodology for modeling and identifying transformer internal faults by using transmission line method (TLM) and fuzzy reasoning technique based on dynamic principal component analysis (PCA), respectively. The transformer has been modeled considering non-linearities as hysteresis and saturation. Transformer internal fault currents are successfully discriminated from the rated currents. The degree and priority of transformer internal faults are obtained by the proposed method. It is suited for implementation on computers because of no computation complexity. Hence, the proposed algorithm can be used effectively in real-time fault identification problems. (C) 2007 The Franklin Institute. Published by Elsevier Ltd. All rights reserved
Abstract: In this paper, a different internal fault modeling and an identification algorithm are presented. There has been an increasing concern about turn-to-turn faults in transformers because of the high costs of unexpected outages. It is not always possible to analyze the transformer behavior under such faults at rated conditions, since the tests are highly destructive. To develop transformer internal fault detection technique, a transformer model to simulate internal faults is required. This paper describes a novel technique and methodology for modeling and identifying transformer internal faults by using transmission line method (TLM) and fuzzy reasoning technique based on dynamic principal component analysis (PCA), respectively. The transformer has been modeled considering non-linearities as hysteresis and saturation. Transformer internal fault currents are successfully discriminated from the rated currents. The degree and priority of transformer internal faults are obtained by the proposed method. It is suited for implementation on computers because of no computation complexity. Hence, the proposed algorithm can be used effectively in real-time fault identification problems. (C) 2007 The Franklin Institute. Published by Elsevier Ltd. All rights reserved
50. Lu, Y.P., Yu, M., Lai, L.L., Lin, X., 2008. A new fuzzy neural network strategy of insulators contamination detection for power system transmission line. International Journal of Pattern Recognition and Artificial Intelligence 22, 55-64.
Abstract: The detection of insulators contamination is difficult in power systems because many factors can influence the pollution. The contamination condition of insulators is usually estimated by detecting the root mean square (r.m.s) of surface leakage current via online-monitoring system. It ignores the influence of environmental factors, such as temperature, humidity, etc. As these factors are fuzzy-characterized, a new method based on Fuzzy Neural Network (FNN) is proposed to improve traditional insulation contamination detection. The renewed structure of FNN is put forward. The evaluation of contamination severity of insulators is achieved through FNN, which are trained by the field samples. The results prove the validity of the method proposed in the paper and can be used to eliminate the insulator from flashover fault and improve the condition-based maintenance (CBM)
Abstract: The detection of insulators contamination is difficult in power systems because many factors can influence the pollution. The contamination condition of insulators is usually estimated by detecting the root mean square (r.m.s) of surface leakage current via online-monitoring system. It ignores the influence of environmental factors, such as temperature, humidity, etc. As these factors are fuzzy-characterized, a new method based on Fuzzy Neural Network (FNN) is proposed to improve traditional insulation contamination detection. The renewed structure of FNN is put forward. The evaluation of contamination severity of insulators is achieved through FNN, which are trained by the field samples. The results prove the validity of the method proposed in the paper and can be used to eliminate the insulator from flashover fault and improve the condition-based maintenance (CBM)
51. Valsan, S.P., Swarup, K.S., 2008. Fault detection and classification logic for transmission lines using multi-resolution wavelet analysis. Electric Power Components and Systems 36, 321-344.
Abstract: This article presents a fast, hardware efficient logic for fault detection and classification in transmission lines. The proposed logic employs only one-terminal current samples and is based on multi-resolution wavelet analysis. First-level high-frequency details of the modal currents in the range of 5 to 10 kHz are extracted. Depending on the amount of high-frequency components in the transformed current signals after processing, the faults are classified into ten types. An adaptive threshold value is chosen, rather than a fixed threshold in the case of faults involving the ground, to make the classification reliable and accurate. The validity of the proposed logic was exhaustively tested by simulating various types of faults on a system modeled in Alternative Transient Program (ATP)/Electromagnetic Transient Program (EMTP).The proposed logic was found to be acceptably reliable and accurate even in the presence of fault resistance and current transformer (CT) saturation
Abstract: This article presents a fast, hardware efficient logic for fault detection and classification in transmission lines. The proposed logic employs only one-terminal current samples and is based on multi-resolution wavelet analysis. First-level high-frequency details of the modal currents in the range of 5 to 10 kHz are extracted. Depending on the amount of high-frequency components in the transformed current signals after processing, the faults are classified into ten types. An adaptive threshold value is chosen, rather than a fixed threshold in the case of faults involving the ground, to make the classification reliable and accurate. The validity of the proposed logic was exhaustively tested by simulating various types of faults on a system modeled in Alternative Transient Program (ATP)/Electromagnetic Transient Program (EMTP).The proposed logic was found to be acceptably reliable and accurate even in the presence of fault resistance and current transformer (CT) saturation
52. 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
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
53. 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
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
54. Tai, N.L., Chen, J.J., 2008. Wavelet-based approach for high impedance fault detection of high voltage transmission line. European Transactions on Electrical Power 18, 79-92.
Abstract: This paper presents a new method for high impedance single-phase ground fault (HIF) detection based on wavelet transform (WT) in the high voltage transmission line. As high impedance single-phase ground faults usually have low fault currents, it cannot be easily detected by the conventional protection. The voltages and currents vary simultaneously when a ground fault occurs in the transmission lines, even if it is grounded with a high impedance. Therefore, the signals measured by the protective device contain significant transient components. They have much more fault information than the steady components. With the WT the modulus maxima of the zero sequence current, the faulted phase current, and the zero sequence voltage present special characteristics which can be used to detect HIF The new scheme can also discriminate if the ground fault locates in the forward zone or the backward zone. The realization of the proposed protection device is also described in this paper. Both simulation and field results show that the scheme can detect HIF with high reliability during all operating conditions. Copyright (C) 2007 John Wiley & Sons, Ltd
Abstract: This paper presents a new method for high impedance single-phase ground fault (HIF) detection based on wavelet transform (WT) in the high voltage transmission line. As high impedance single-phase ground faults usually have low fault currents, it cannot be easily detected by the conventional protection. The voltages and currents vary simultaneously when a ground fault occurs in the transmission lines, even if it is grounded with a high impedance. Therefore, the signals measured by the protective device contain significant transient components. They have much more fault information than the steady components. With the WT the modulus maxima of the zero sequence current, the faulted phase current, and the zero sequence voltage present special characteristics which can be used to detect HIF The new scheme can also discriminate if the ground fault locates in the forward zone or the backward zone. The realization of the proposed protection device is also described in this paper. Both simulation and field results show that the scheme can detect HIF with high reliability during all operating conditions. Copyright (C) 2007 John Wiley & Sons, Ltd
55. Mohanty, S.R., Pradhan, A.K., Routray, A., 2008. A cumulative sum-based fault detector for power system relaying application. Ieee Transactions on Power Delivery 23, 79-86.
Abstract: In this paper, a cumulative-sum-based fault detection algorithm is proposed for the power system relaying application. Literature suggests the successful application of this method to process control systems where the deviation of parameters is tracked to indicate any abnormal conditions. The effectiveness of the algorithm is found to be better than the traditional methods in the presence of noise, system frequency deviation, and other uncertainties. It is also not affected by load change in a system. Above all, it provides relatively higher index values,without compromising detection speed
Abstract: In this paper, a cumulative-sum-based fault detection algorithm is proposed for the power system relaying application. Literature suggests the successful application of this method to process control systems where the deviation of parameters is tracked to indicate any abnormal conditions. The effectiveness of the algorithm is found to be better than the traditional methods in the presence of noise, system frequency deviation, and other uncertainties. It is also not affected by load change in a system. Above all, it provides relatively higher index values,without compromising detection speed
56. Zin, A.A.M., Karim, S.P.A., 2007. The utilization of digital fault recorders in protection, system analysis on Tenaga Nasional Berhad transmission system. Ieee Transactions on Power Delivery 22, 2040-2046.
Abstract: The protection system is a very critical element in a power system. It is security to the power system for isolating only, the faulty plant as fast as possible. A simple fault can lead to a cascade of tripping if it is not isolated accurately and fast enough by the, protection system. Furthermore, protection system analysis is a complicated task for inexperienced engineers. Most of the analysis relied mainly on the relay indications which could lead to incorrect analysis due to the uncertainty of the correct relay operations and time tagging. Therefore, I it is an urgent requirement to explore protection system analysis to improve system reliability. This paper describes a method of early detection of protection system failures in Tenaga Nasional Berhad's Transmission Grid using digital fault recorders. The method has demonstrated to be more accurate, thus enabling faster decision making and shorter interruption time
Abstract: The protection system is a very critical element in a power system. It is security to the power system for isolating only, the faulty plant as fast as possible. A simple fault can lead to a cascade of tripping if it is not isolated accurately and fast enough by the, protection system. Furthermore, protection system analysis is a complicated task for inexperienced engineers. Most of the analysis relied mainly on the relay indications which could lead to incorrect analysis due to the uncertainty of the correct relay operations and time tagging. Therefore, I it is an urgent requirement to explore protection system analysis to improve system reliability. This paper describes a method of early detection of protection system failures in Tenaga Nasional Berhad's Transmission Grid using digital fault recorders. The method has demonstrated to be more accurate, thus enabling faster decision making and shorter interruption time
57. Samantaray, S.R., Dash, P.K., 2007. Wavelet packet-based digital relaying for advanced series compensated line. Iet Generation Transmission & Distribution 1, 784-792.
Abstract: A new approach for the protection of thyristor-controlled series-compensated (TCSC) line using wavelet packets transform (WPT) is presented. The proposed method uses one cycle post-fault-current samples just after fault inception, which is processed through WPT and decomposed into various decomposition levels. The decomposed components are grouped together to provide different frequency sub-bands. Then the phase selection signal (PSS) and section identification signal (SIS) are computed to identify the faulty phase and faulty section, respectively, involved in the fault process in transmission line including TCSC. A threshold value (THD) is selected for PSS, and PSS above THD describes the faulty phase involved, otherwise not. Similarly, another THD is selected for SIS, and SIS below THD describes fault that includes TCSC, otherwise fault that does not include TCSC. As PSS takes half cycle after fault inception to identify the faulty phase and then triggers SIS, the faulty phases and faulty sections are identified within one cycle of fault inception. The proposed WPT algorithm is also tested on physical transmission line model with TCSC, under wide variations in operating conditions and provides accurate results. Thus, the proposed method provides accurate and fast protection measures for TCSC-based line
Abstract: A new approach for the protection of thyristor-controlled series-compensated (TCSC) line using wavelet packets transform (WPT) is presented. The proposed method uses one cycle post-fault-current samples just after fault inception, which is processed through WPT and decomposed into various decomposition levels. The decomposed components are grouped together to provide different frequency sub-bands. Then the phase selection signal (PSS) and section identification signal (SIS) are computed to identify the faulty phase and faulty section, respectively, involved in the fault process in transmission line including TCSC. A threshold value (THD) is selected for PSS, and PSS above THD describes the faulty phase involved, otherwise not. Similarly, another THD is selected for SIS, and SIS below THD describes fault that includes TCSC, otherwise fault that does not include TCSC. As PSS takes half cycle after fault inception to identify the faulty phase and then triggers SIS, the faulty phases and faulty sections are identified within one cycle of fault inception. The proposed WPT algorithm is also tested on physical transmission line model with TCSC, under wide variations in operating conditions and provides accurate results. Thus, the proposed method provides accurate and fast protection measures for TCSC-based line
59. 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
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
61. 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
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
62. 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)
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)
63. 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
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
64. 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
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
66. Dash, P.K., Samantaray, S.R., Panda, G., 2007. Fault classification and section identification of an advanced series-compensated transmission line using support vector machine. Ieee Transactions on Power Delivery 22, 67-73.
Abstract: Distance protection of flexible ac transmission lines, including the thyristor-controlled series compensator (TCSC), static synchronous compensator, and static var compensator has been a very challenging task. This paper presents a new approach for the protection of TCSC line using a support vector machine (SVM). The proposed method uses postfault current samples for half cycle (ten samples) from the inception of the fault and firing angle as inputs to the SVM. Three SVMs are trained to provide fault classification, ground detection, and section identification, respectively, for the line using TCSC. The SVMs are trained with polynomial kernel and Gaussian kernel with different parameter values to get the most optimized classifier. The proposed method converges very fast with fewer numbers of training samples compared to neural-network and neuro-fuzzy systems which indicates fastness and accuracy of the proposed method for,protection of the transmission line with TCSC
Abstract: Distance protection of flexible ac transmission lines, including the thyristor-controlled series compensator (TCSC), static synchronous compensator, and static var compensator has been a very challenging task. This paper presents a new approach for the protection of TCSC line using a support vector machine (SVM). The proposed method uses postfault current samples for half cycle (ten samples) from the inception of the fault and firing angle as inputs to the SVM. Three SVMs are trained to provide fault classification, ground detection, and section identification, respectively, for the line using TCSC. The SVMs are trained with polynomial kernel and Gaussian kernel with different parameter values to get the most optimized classifier. The proposed method converges very fast with fewer numbers of training samples compared to neural-network and neuro-fuzzy systems which indicates fastness and accuracy of the proposed method for,protection of the transmission line with TCSC
67. 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
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
68. 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
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
69. Silva, K.M., Souza, B.A., Brito, N.S.D., 2006. Fault detection and classification in transmission lines-based on wavelet transform and ANN. Ieee Transactions on Power Delivery 21, 2058-2063.
Abstract: This paper proposes a novel method for transmission-line fault detection and classification using oscillographic data. The fault detection and its clearing time are determined based on a set of rules obtained from the current waveform analysis in time and wavelet domains. The method is able to single out faults from other power-quality disturbances, such as voltage sags and oscillatory transients, which are common in power systems operation. An artificial neural network classifies the fault from the voltage and current waveforms pattern recognition in the time domain. The method has been used for fault detection and classification from real oscillographic data of a Brazilian utility company with excellent results
Abstract: This paper proposes a novel method for transmission-line fault detection and classification using oscillographic data. The fault detection and its clearing time are determined based on a set of rules obtained from the current waveform analysis in time and wavelet domains. The method is able to single out faults from other power-quality disturbances, such as voltage sags and oscillatory transients, which are common in power systems operation. An artificial neural network classifies the fault from the voltage and current waveforms pattern recognition in the time domain. The method has been used for fault detection and classification from real oscillographic data of a Brazilian utility company with excellent results
70. Wang, X.H., Song, Y.H., 2006. Sheath fault detection and classification based on wavelet analysis. European Transactions on Electrical Power 16, 327-344.
Abstract: This paper presents a wavelet based algorithm to detect and classify sheath insulation faults on underground transmission cables. This algorithm can detect a high impedance sheath to earth fault, classify it, and discriminate it from other phenomena, such as load change, harmonics and surges on the cores. For the development of the algorithm, a simplified fault model is introduced to simulate a sheath to earth fault on a power transmission cable. Before applying wavelet analysis, an 'adaptive noise cancelling' (ANC) technique is used to extract the fault signal. Simulation studies are reported on a 300 mm(2) concentric copper PVC insulated bonding lead. Copyright (C) 2006 John Wiley & Sons, Ltd
Abstract: This paper presents a wavelet based algorithm to detect and classify sheath insulation faults on underground transmission cables. This algorithm can detect a high impedance sheath to earth fault, classify it, and discriminate it from other phenomena, such as load change, harmonics and surges on the cores. For the development of the algorithm, a simplified fault model is introduced to simulate a sheath to earth fault on a power transmission cable. Before applying wavelet analysis, an 'adaptive noise cancelling' (ANC) technique is used to extract the fault signal. Simulation studies are reported on a 300 mm(2) concentric copper PVC insulated bonding lead. Copyright (C) 2006 John Wiley & Sons, Ltd
71. Erenturk, K., 2005. A new digital protective relay based on fuzzy logic and value estimation. Iranian Journal of Science and Technology Transaction A-Science 29, 267-276.
Abstract: In this paper, design and application of a new digital protective relay based on fuzzy logic and value estimation to a radial power system protection was presented. A novel approach based on value estimation was investigated for the proposed fuzzy logic based protective relay. In addition to the theoretical aspect of fuzzy logic, mathematical definition of value estimation, detection and measurement of faulty current, determination of its duration, decision mechanism and detailed system architecture were also introduced. ne examined technique based on fuzzy logic and value estimation to control the protection action of the protective relay was intended to improve the performance of a conventional protective relay control for human safety and system reliability with the use of a fuzzy logic controller. The difference between estimated and sampled values was used to form the rule base. Proposed relay architecture was used as a detector and was developed to predict faults and to protect particular sections of a designed prototype radial power system at an early stage. Performance analysis was made, and related results and discussion were given
Abstract: In this paper, design and application of a new digital protective relay based on fuzzy logic and value estimation to a radial power system protection was presented. A novel approach based on value estimation was investigated for the proposed fuzzy logic based protective relay. In addition to the theoretical aspect of fuzzy logic, mathematical definition of value estimation, detection and measurement of faulty current, determination of its duration, decision mechanism and detailed system architecture were also introduced. ne examined technique based on fuzzy logic and value estimation to control the protection action of the protective relay was intended to improve the performance of a conventional protective relay control for human safety and system reliability with the use of a fuzzy logic controller. The difference between estimated and sampled values was used to form the rule base. Proposed relay architecture was used as a detector and was developed to predict faults and to protect particular sections of a designed prototype radial power system at an early stage. Performance analysis was made, and related results and discussion were given
76. Ukil, A., Zivanovic, R., 2006. Abrupt change detection in power system fault analysis using adaptive whitening filter and wavelet transform. Electric Power Systems Research 76, 815-823.
Abstract: This paper describes the application of the adaptive whitening filter and the wavelet transform used to detect the abrupt changes in the signals recorded during disturbances in the electrical power network in South Africa. Main focus has been to estimate exactly the time-instants of the changes in the signal model parameters during the pre-fault condition and following events like initiation of fault. circuit-breaker opening, auto-reclosure of the circuit-breakers. The key idea is to decompose the fault signals, de-noised using the adaptive whitening filter, into effective detailed and smoothed version using the multiresolution signal decomposition technique based on discrete wavelet transform. Then we apply the threshold method on the decomposed signals to estimate the change time-instants, segmenting the fault signals into the event-specific sections for further signal processing and analysis. This paper presents application on the recorded signals in the power transmission network of South Africa. (C) 2005 Elsevier B.V. All rights reserved
Abstract: This paper describes the application of the adaptive whitening filter and the wavelet transform used to detect the abrupt changes in the signals recorded during disturbances in the electrical power network in South Africa. Main focus has been to estimate exactly the time-instants of the changes in the signal model parameters during the pre-fault condition and following events like initiation of fault. circuit-breaker opening, auto-reclosure of the circuit-breakers. The key idea is to decompose the fault signals, de-noised using the adaptive whitening filter, into effective detailed and smoothed version using the multiresolution signal decomposition technique based on discrete wavelet transform. Then we apply the threshold method on the decomposed signals to estimate the change time-instants, segmenting the fault signals into the event-specific sections for further signal processing and analysis. This paper presents application on the recorded signals in the power transmission network of South Africa. (C) 2005 Elsevier B.V. All rights reserved
77. Aldeen, M., Crusca, F., 2006. Observer-based fault detection and identification scheme for power systems. Iee Proceedings-Generation Transmission and Distribution 153, 71-79.
Abstract: A scheme suitable for the detection and identification of faults in power systems is presented. Two notable contributions are made: a re-modelling of faulty components of power systems that is applicable to both normal and faulty conditions, and a fault detection scheme for power systems. The faults are modelled as unknown inputs, decoupled from the state and output measurements through coordinate transformations, and then estimated through the use of observer theory. The proposed scheme is applied to a power system consisting of a synchronous generator, an exciter, a turbine and speed-governing system, and a network of fines and loads. The case where faults occur on the transmission network is considered. It is shown that the proposed fault detection procedure allows for the real-time identification of the occurrence of the faults and determines their exact locations. Results of detailed simulation studies involving disturbances and faults occurring in linear and nonlinear models of the power system are presented
Abstract: A scheme suitable for the detection and identification of faults in power systems is presented. Two notable contributions are made: a re-modelling of faulty components of power systems that is applicable to both normal and faulty conditions, and a fault detection scheme for power systems. The faults are modelled as unknown inputs, decoupled from the state and output measurements through coordinate transformations, and then estimated through the use of observer theory. The proposed scheme is applied to a power system consisting of a synchronous generator, an exciter, a turbine and speed-governing system, and a network of fines and loads. The case where faults occur on the transmission network is considered. It is shown that the proposed fault detection procedure allows for the real-time identification of the occurrence of the faults and determines their exact locations. Results of detailed simulation studies involving disturbances and faults occurring in linear and nonlinear models of the power system are presented
78. 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
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
79. Bouthiba, T., 2005. Fault detection and classification technique in EHV transmission lines based on Artificial Neural Networks. European Transactions on Electrical Power 15, 443-454.
Abstract: This paper investigates a new approach based on Artificial Neural Networks (ANNs) for real-time fault detection and classification in power transmission lines which can be used in digital power system protection. The Fault Detector and Classifier (FDC) consists of four independent ANNs. The technique uses consecutive magnitude current and voltage data at one terminal as inputs to the corresponding ANN. The ANN outputs are used to indicate simultaneously the presence and the type of the fault. The FDC is tested under different fault types, fault locations, fault resistances and fault inception angles. All test results show that the proposed FDC can be used for very high speed digital relaying. Copyright (c) 2005 John Wiley & Sons, Ltd
Abstract: This paper investigates a new approach based on Artificial Neural Networks (ANNs) for real-time fault detection and classification in power transmission lines which can be used in digital power system protection. The Fault Detector and Classifier (FDC) consists of four independent ANNs. The technique uses consecutive magnitude current and voltage data at one terminal as inputs to the corresponding ANN. The ANN outputs are used to indicate simultaneously the presence and the type of the fault. The FDC is tested under different fault types, fault locations, fault resistances and fault inception angles. All test results show that the proposed FDC can be used for very high speed digital relaying. Copyright (c) 2005 John Wiley & Sons, Ltd
80. Aghaebrahimi, M.R., Khorashadi-Zadeh, H., 2005. A fuzzy neuro approach to fault-type identification for double circuit lines. Ieice Transactions on Information and Systems E88D, 1920-1922.
Abstract: A novel application of fuzzy-neuro approach to protection of double circuit transmission line is demonstrated in this paper. Different system faults on a protected transmission line should be detected and classified rapidly and correctly. Using the proposed approach, fault detection, classification and faulted phase selection could be achieved within a quarter of cycle. Results of performance studies show that the proposed fuzzy-neuro-based module can improve the performance of conventional fault selection algorithms
Abstract: A novel application of fuzzy-neuro approach to protection of double circuit transmission line is demonstrated in this paper. Different system faults on a protected transmission line should be detected and classified rapidly and correctly. Using the proposed approach, fault detection, classification and faulted phase selection could be achieved within a quarter of cycle. Results of performance studies show that the proposed fuzzy-neuro-based module can improve the performance of conventional fault selection algorithms
81. El-Arroudi, K., Joos, G., McGillis, D.T., Brearley, R., 2005. Comprehensive transmission distance protection settings using an intelligent-based analysis of events and consequences. Ieee Transactions on Power Delivery 20, 1817-1824.
Abstract: This paper introduces a new methodology for settings of transmission system distance protection based on an intelligent analysis of events and their consequences. The output of the proposed methodology is comprehensive distance relay settings which include not only the zone reaches and zone time delays, as in the existing approaches, but also the optimal impedance operating characteristics, the fault detection settings, and the required relay sensitivities in terms of voltage and current. The need for this methodology is the result of the increased complexity of interconnected power systems protected with a large number of relays with different relay technologies, such as electromechanical, static, and numerical as well as diversity in their operating algorithms. The relay settings are automatically updated after every major change in the state of the network topology. Since it is not possible to include all design details of the proposed system, sample design events and rules are given to illustrate the proposed methodology
Abstract: This paper introduces a new methodology for settings of transmission system distance protection based on an intelligent analysis of events and their consequences. The output of the proposed methodology is comprehensive distance relay settings which include not only the zone reaches and zone time delays, as in the existing approaches, but also the optimal impedance operating characteristics, the fault detection settings, and the required relay sensitivities in terms of voltage and current. The need for this methodology is the result of the increased complexity of interconnected power systems protected with a large number of relays with different relay technologies, such as electromechanical, static, and numerical as well as diversity in their operating algorithms. The relay settings are automatically updated after every major change in the state of the network topology. Since it is not possible to include all design details of the proposed system, sample design events and rules are given to illustrate the proposed methodology
82. Wouters, P.A.A.F., van der Wielen, P.C.J.M., Veen, J., Wagenaars, P., Steennis, E.F., 2005. Effect of cable load impedance on coupling schemes for MV power line communication. Ieee Transactions on Power Delivery 20, 638-645.
Abstract: Coupling of carrier wave frequencies up to 95 kHz (within the European CENELEC A-band) for online diagnostic data transfer in medium voltage cables is studied. Inductive and capacitive signal coupling is considered not only on basis of technical performance, but also on basis of practical aspects. The effectiveness of coupling schemes depends on the impedances of substation equipment at the cable terminals. The frequency response of a 10-kV, 400-kVA three-phase cast resin distribution transformer is investigated. In the frequency range of interest, the behavior is well described by a capacitance of typically 1 nF. The signal transfer over a 4-km paper cable, terminated by various load impedances to mimic real equipment is studied. From the results it is concluded that for inductive coupling performance within the CENELEC A-band may be sufficient, except for substations at the end of a grid. Transferring signals containing frequencies up to several megahertz, which is already required for synchronization of partial discharge detection and location equipment, is feasible under all conditions. Measurements on life substations indicate that up to these frequencies substation components can still be accurately modeled as lumped circuit impedances
Abstract: Coupling of carrier wave frequencies up to 95 kHz (within the European CENELEC A-band) for online diagnostic data transfer in medium voltage cables is studied. Inductive and capacitive signal coupling is considered not only on basis of technical performance, but also on basis of practical aspects. The effectiveness of coupling schemes depends on the impedances of substation equipment at the cable terminals. The frequency response of a 10-kV, 400-kVA three-phase cast resin distribution transformer is investigated. In the frequency range of interest, the behavior is well described by a capacitance of typically 1 nF. The signal transfer over a 4-km paper cable, terminated by various load impedances to mimic real equipment is studied. From the results it is concluded that for inductive coupling performance within the CENELEC A-band may be sufficient, except for substations at the end of a grid. Transferring signals containing frequencies up to several megahertz, which is already required for synchronization of partial discharge detection and location equipment, is feasible under all conditions. Measurements on life substations indicate that up to these frequencies substation components can still be accurately modeled as lumped circuit impedances
83. Xu, L., Andersen, B.R., Cartwright, P., 2005. Multilevel-converter-based VSC transmission operating under fault AC conditions. Iee Proceedings-Generation Transmission and Distribution 152, 185-193.
Abstract: A study of a floating-capacitor (FC) multilevel-converter-based VSC transmission system operating under unbalanced AC conditions is presented. The control strategy is based on the use of two controllers, i.e. a main controller, which is implemented in the synchronous d-q frame without involving positive and negative sequence decomposition, and an auxiliary controller, which is implemented in the negative sequence d-q frame with the negative sequence current extracted. Automatic power balancing during AC fault is achieved without communication between the two converters by automatic power modulation on the detection of abnormal DC voltages. The impact of unbalanced floating capacitor voltages of the FC converter on power devices is described. A software-based method, which adds square waves whose amplitudes vary with the capacitor voltage errors to the nominal modulation signals for fast capacitor voltage balancing during faults, is proposed. Simulations on a 300 kV DC, 300 MW VSC transmission system based on a four-level FC converter show good performance of the proposed control strategy during unbalanced conditions caused by single-phase to ground fault
Abstract: A study of a floating-capacitor (FC) multilevel-converter-based VSC transmission system operating under unbalanced AC conditions is presented. The control strategy is based on the use of two controllers, i.e. a main controller, which is implemented in the synchronous d-q frame without involving positive and negative sequence decomposition, and an auxiliary controller, which is implemented in the negative sequence d-q frame with the negative sequence current extracted. Automatic power balancing during AC fault is achieved without communication between the two converters by automatic power modulation on the detection of abnormal DC voltages. The impact of unbalanced floating capacitor voltages of the FC converter on power devices is described. A software-based method, which adds square waves whose amplitudes vary with the capacitor voltage errors to the nominal modulation signals for fast capacitor voltage balancing during faults, is proposed. Simulations on a 300 kV DC, 300 MW VSC transmission system based on a four-level FC converter show good performance of the proposed control strategy during unbalanced conditions caused by single-phase to ground fault
84. Samuel, P.D., Pines, D.J., 2005. A review of vibration-based techniques for helicopter transmission diagnostics. Journal of Sound and Vibration 282, 475-508.
Abstract: Over the past 25 years, much research has been devoted to the development of Health and Usage Monitoring (HUM) systems for rotorcraft gearbox and drivetrain components. The promise of HUM systems is the ability to provide accurate information regarding the condition of various flight critical components. This paper reviews the state of the art in vibration-based helicopter transmission diagnostics. The development of various damage detection techniques is discussed from a historical perspective, and the ability of these techniques to detect damage in helicopter transmissions is reviewed. Emerging research trends suggest that improvements in signal processing, sensor development and individual-tooth mesh waveform modelling could improve the performance of current and future helicopter transmission diagnostics. (c) 2004 Elsevier Ltd. All rights reserved
Abstract: Over the past 25 years, much research has been devoted to the development of Health and Usage Monitoring (HUM) systems for rotorcraft gearbox and drivetrain components. The promise of HUM systems is the ability to provide accurate information regarding the condition of various flight critical components. This paper reviews the state of the art in vibration-based helicopter transmission diagnostics. The development of various damage detection techniques is discussed from a historical perspective, and the ability of these techniques to detect damage in helicopter transmissions is reviewed. Emerging research trends suggest that improvements in signal processing, sensor development and individual-tooth mesh waveform modelling could improve the performance of current and future helicopter transmission diagnostics. (c) 2004 Elsevier Ltd. All rights reserved
85. Osman, A.H., Malik, O., 2004. Experimental test results for a parallel transmission lines protection scheme using wavelet transform. Iee Proceedings-Generation Transmission and Distribution 151, 713-720.
Abstract: A scheme for the protection of parallel transmission fines using wavelet transform (WT) has been implemented and results of experimental tests on a physical power system model are described. The relaying scheme depends on the three line voltages and the six fine currents of the two parallel lines at each end. Fault detection, fault discrimination and calculation of the phasors of the measured signals are done using WT: The performance of the proposed scheme has been investigated by a number of online tests. The results show that all types of shortcircuit faults can be correctly identified in less than one cycle of the fundamental frequency
Abstract: A scheme for the protection of parallel transmission fines using wavelet transform (WT) has been implemented and results of experimental tests on a physical power system model are described. The relaying scheme depends on the three line voltages and the six fine currents of the two parallel lines at each end. Fault detection, fault discrimination and calculation of the phasors of the measured signals are done using WT: The performance of the proposed scheme has been investigated by a number of online tests. The results show that all types of shortcircuit faults can be correctly identified in less than one cycle of the fundamental frequency
86. Jamil, M., 2005. Current status of Petri nets theory in power systems. Electric Power Components and Systems 33, 263-276.
Abstract: For the last two decades increasing attention has been given to Petri net's applications for the representation and analysis of large, complex, distributed, stochastic and discrete-event systems like flexible manufacturing, industrial control systems, communication protocol, distributed-software systems, distributed-database system, multiprocessor memory systems, data flow computing systems, fault-tolerant systems, and computer industries. Since power system is a large geographically wide distributed system, in the recent past, application of Petri net's theory in power systems have also been reported. This article presents literature survey of recent papers published in the area of power systems using Petri nets. Basics of Petri net's theory and its different forms applicable to power systems are also discussed. A method of detecting type of faults on three phase transmission line by using Petri net theory is discussed in details. Different examples based on Petri nets shows that such methodology is more efficient than the traditional approaches especially when the complexity of the problem increases
Abstract: For the last two decades increasing attention has been given to Petri net's applications for the representation and analysis of large, complex, distributed, stochastic and discrete-event systems like flexible manufacturing, industrial control systems, communication protocol, distributed-software systems, distributed-database system, multiprocessor memory systems, data flow computing systems, fault-tolerant systems, and computer industries. Since power system is a large geographically wide distributed system, in the recent past, application of Petri net's theory in power systems have also been reported. This article presents literature survey of recent papers published in the area of power systems using Petri nets. Basics of Petri net's theory and its different forms applicable to power systems are also discussed. A method of detecting type of faults on three phase transmission line by using Petri net theory is discussed in details. Different examples based on Petri nets shows that such methodology is more efficient than the traditional approaches especially when the complexity of the problem increases
87. 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
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
88. 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
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
89. 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
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
90. 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
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
91. Shoureshi, R.A., Lim, S.W., Dolev, E., Sarusi, B., 2004. Electro-magnetic-acoustic transducers for automatic monitoring and health assessment of transmission lines. Journal of Dynamic Systems Measurement and Control-Transactions of the Asme 126, 303-308.
Abstract: This paper presents analysis, design, development, and experimental verification of a non-destructive monitoring system for diagnosis of mechanical integrity of electric conductors based on the concept of Electro-Magnetic-Acoustic Transducers (EMAT). Electric conductors, in general, are exposed to harsh environments. Such conductors include electric transmission lines, anchor rods, and ground mat risers. For automatic failure detection and assessment of mechanical integrity of these conductors, in addition to an effective transducer feature extraction and pattern recognition techniques have to be employed. Details of the sensor design, neural-based signature analysis, feature extraction, and experimental results of fault detection techniques are presented
Abstract: This paper presents analysis, design, development, and experimental verification of a non-destructive monitoring system for diagnosis of mechanical integrity of electric conductors based on the concept of Electro-Magnetic-Acoustic Transducers (EMAT). Electric conductors, in general, are exposed to harsh environments. Such conductors include electric transmission lines, anchor rods, and ground mat risers. For automatic failure detection and assessment of mechanical integrity of these conductors, in addition to an effective transducer feature extraction and pattern recognition techniques have to be employed. Details of the sensor design, neural-based signature analysis, feature extraction, and experimental results of fault detection techniques are presented
92. Li, W., Mechefske, C.K., 2004. Induction motor fault detection using vibration and stator current methods. Insight 46, 473-478.
Abstract: Induction motors are widely used in industry as prime electromechanical energy conversion devices. Consequently, the condition monitoring and fault diagnosis of induction motors have received significant attention recently and become an integrated part of various maintenance strategies (for example preventive, condition-based and reliability-based maintenance). This paper presents a comparison of results of induction motor broken rotor bar fault detection using vibration and stator current methods. A broken rotor bar fault was induced into in a variable speed three-phase induction motor. Both the vibration and stator current signatures were acquired under different speed and load conditions. The fault detection sensitivities of vibration and stator current methods are evaluated. This paper also addresses the relationship between current and vibration signatures under normal and faulty motor conditions using correlation and frequency response methods. This relationship is desirable in order to determine the fault signature transmission mechanism and to exclude the irrelevant vibration sources so as to enhance fault detection accuracy. The relationship, studied during steady-state operation and start-up, enabled the identification of the vibrations from other sources
Abstract: Induction motors are widely used in industry as prime electromechanical energy conversion devices. Consequently, the condition monitoring and fault diagnosis of induction motors have received significant attention recently and become an integrated part of various maintenance strategies (for example preventive, condition-based and reliability-based maintenance). This paper presents a comparison of results of induction motor broken rotor bar fault detection using vibration and stator current methods. A broken rotor bar fault was induced into in a variable speed three-phase induction motor. Both the vibration and stator current signatures were acquired under different speed and load conditions. The fault detection sensitivities of vibration and stator current methods are evaluated. This paper also addresses the relationship between current and vibration signatures under normal and faulty motor conditions using correlation and frequency response methods. This relationship is desirable in order to determine the fault signature transmission mechanism and to exclude the irrelevant vibration sources so as to enhance fault detection accuracy. The relationship, studied during steady-state operation and start-up, enabled the identification of the vibrations from other sources
93. Moravej, Z., Sanaye-Pasand, M., 2004. A novel approach for protection and condition monitoring of power transformer using MRBFNN. Electric Power Components and Systems 32, 491-503.
Abstract: This article presents differential relaying and condition monitoring of power transformer using 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. This ANN-based scheme monitors operating conditions of the transformer and detects the fault and issues the trip signal in case of an internal fault. It has been realized through two different ANN structures using the minimal radial basis function (MRBF) learning algorithm. The proposed protection scheme has been evaluated using simulated data obtained through EMTP/ATP package. The results amply demonstrate the capabilities of the proposed fault detector (FD) and condition monitor (CM) in terms of accuracy and speed with respect to detection of fault, classification and pattern recognition of different events of power transformer. The number of training patterns and training time are drastically reduced and significant accuracy is achieved
Abstract: This article presents differential relaying and condition monitoring of power transformer using 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. This ANN-based scheme monitors operating conditions of the transformer and detects the fault and issues the trip signal in case of an internal fault. It has been realized through two different ANN structures using the minimal radial basis function (MRBF) learning algorithm. The proposed protection scheme has been evaluated using simulated data obtained through EMTP/ATP package. The results amply demonstrate the capabilities of the proposed fault detector (FD) and condition monitor (CM) in terms of accuracy and speed with respect to detection of fault, classification and pattern recognition of different events of power transformer. The number of training patterns and training time are drastically reduced and significant accuracy is achieved
94. Youssef, O.A.S., 2004. Combined fuzzy-logic wavelet-based fault classification technique for power system relaying. Ieee Transactions on Power Delivery 19, 582-589.
Abstract: This paper presents a new approach to real-time fault classification in power transmission systems using fuzzy-logic-based multicriteria approach. Only the three line currents are utilized to detect fault types such as LG, LL, and LLG, and then to define the faulty line. An online wavelet-based preprocessor stage,[1]-[4] is used with data window of ten samples (based on 4.5-kHz sampling rate and 50-Hz power frequency). The multicriteria algorithm is developed based on fuzzy sets for the decision-making part of the scheme. Computer simulation has been conducted using EMTP programs. Results are shown and they indicate that this approach can be used as an effective tool for high-speed digital relaying, as the correct detection is achieved in less than half a cycle and that computational burden is much simpler than the recently postulated fault classification techniques
Abstract: This paper presents a new approach to real-time fault classification in power transmission systems using fuzzy-logic-based multicriteria approach. Only the three line currents are utilized to detect fault types such as LG, LL, and LLG, and then to define the faulty line. An online wavelet-based preprocessor stage,[1]-[4] is used with data window of ten samples (based on 4.5-kHz sampling rate and 50-Hz power frequency). The multicriteria algorithm is developed based on fuzzy sets for the decision-making part of the scheme. Computer simulation has been conducted using EMTP programs. Results are shown and they indicate that this approach can be used as an effective tool for high-speed digital relaying, as the correct detection is achieved in less than half a cycle and that computational burden is much simpler than the recently postulated fault classification techniques
95. Osman, A.H., Malik, O.P., 2004. Protection of parallel transmission lines using wavelet transform. Ieee Transactions on Power Delivery 19, 49-55.
Abstract: A new scheme to enhance the solution of the problems associated with parallel transmission line protection is presented in this paper. The scheme depends on the three line voltages and the six line currents of the two parallel lines at each end. Fault detection, fault discrimination, and calculation of the phasors of the measured signals are done by using wavelet transform (WT). By comparing the magnitudes of the estimated current phasors of the corresponding phases on both lines, internal faults on the parallel lines can be identified. Also, by calculating the distance element of the phases on which a disturbance is detected and having a very small current difference magnitude can enhance and strengthen the scheme. Studies show that all types of faults at different loading conditions can be correctly identified in less than one cycle of the fundamental frequency
Abstract: A new scheme to enhance the solution of the problems associated with parallel transmission line protection is presented in this paper. The scheme depends on the three line voltages and the six line currents of the two parallel lines at each end. Fault detection, fault discrimination, and calculation of the phasors of the measured signals are done by using wavelet transform (WT). By comparing the magnitudes of the estimated current phasors of the corresponding phases on both lines, internal faults on the parallel lines can be identified. Also, by calculating the distance element of the phases on which a disturbance is detected and having a very small current difference magnitude can enhance and strengthen the scheme. Studies show that all types of faults at different loading conditions can be correctly identified in less than one cycle of the fundamental frequency
96. Youssef, O.A.S., 2004. A novel fuzzy-logic-based phase selection technique for power system relaying. Electric Power Systems Research 68, 175-184.
Abstract: Fast tripping and consequent single-pole auto-reclosure of the faulted phase for single-phase earth faults is extensively used in long line applications. Traditional phase selection techniques can suffer some drawbacks due to their dependency on varying system and fault conditions. However, with the advent of fuzzy-logic techniques, and their ability to map complex and non-linear power system configurations provide a very attractive solution to accurate and fast phase selection procedure. This paper presents a new approach to real-time phase selection in power transmission systems using fuzzy-logic-based multi-criteria approach. Only the three line currents are utilised to detect the faulted phase. An online wavelet-based pre-processor stage [IEEE Trans. Power Delivery, 18 (4) (2003) 1158; IEEE Trans. Power delivery 17(4) (2002) 908; IEEE Trans. Power Delivery, 18 (1) (2003) 170; Paper # 01TD069, IEEE T&D Conference, 28 October-2 November 2001, Atlanta, GA] is used with 10 samples data window (based on 4.5 kHz sampling rate and 50 Hz power frequency). The paper demonstrates the multi-criteria algorithm that is based on fuzzy sets for the decision making part of the scheme. Computer simulation have been conducted using EMTP programs. Results proved that the correct detection is achieved in less than half a cycle and that computational burden is simpler than the recently postulated phase selection techniques, and this approach can be used as an effective tool for high speed digital relaying. (C) 2003 Elsevier B.V. All rights reserved
Abstract: Fast tripping and consequent single-pole auto-reclosure of the faulted phase for single-phase earth faults is extensively used in long line applications. Traditional phase selection techniques can suffer some drawbacks due to their dependency on varying system and fault conditions. However, with the advent of fuzzy-logic techniques, and their ability to map complex and non-linear power system configurations provide a very attractive solution to accurate and fast phase selection procedure. This paper presents a new approach to real-time phase selection in power transmission systems using fuzzy-logic-based multi-criteria approach. Only the three line currents are utilised to detect the faulted phase. An online wavelet-based pre-processor stage [IEEE Trans. Power Delivery, 18 (4) (2003) 1158; IEEE Trans. Power delivery 17(4) (2002) 908; IEEE Trans. Power Delivery, 18 (1) (2003) 170; Paper # 01TD069, IEEE T&D Conference, 28 October-2 November 2001, Atlanta, GA] is used with 10 samples data window (based on 4.5 kHz sampling rate and 50 Hz power frequency). The paper demonstrates the multi-criteria algorithm that is based on fuzzy sets for the decision making part of the scheme. Computer simulation have been conducted using EMTP programs. Results proved that the correct detection is achieved in less than half a cycle and that computational burden is simpler than the recently postulated phase selection techniques, and this approach can be used as an effective tool for high speed digital relaying. (C) 2003 Elsevier B.V. All rights reserved
97. Lazkano, A., Ruiz, J., 2003. Discussion of "A novel fault detection technique of high impedance arcing faults in transmission lines using the wavelet transform". Ieee Transactions on Power Delivery 18, 1596.
98. Kim, C.H., Aggarwal, R.K., 2003. Closure on "A novel fault detection technique of high impedance arcing faults in transmission lines using the wavelet transform". Ieee Transactions on Power Delivery 18, 1596-1597.
99. Yeo, S.M., Kim, C.H., Hong, K.S., Lim, Y.B., Aggarwal, R.K., Johns, A.T., Choi, M.S., 2003. A novel algorithm for fault classification in transmission lines using a combined adaptive network and fuzzy inference system. International Journal of Electrical Power & Energy Systems 25, 747-758.
Abstract: Accurate detection and classification of faults on transmission lines is vitally important. In this respect, many different types of faults occur, inter alia low impedance faults (LIF) and high impedance faults (HIF). The latter in particular pose difficulties for the commonly employed conventional overcurrent and distance relays, and if not detected, can cause damage to expensive equipment, threaten life and cause fire hazards. Although HIFs are far less common than LIFs, it is imperative that any protection device should be able to satisfactorily deal with both HIFs and LIFs. Because of the randomness and asymmetric characteristics of HIFs, the modelling of HIF is difficult and many papers relating to various HIF models have been published. In this paper, the model of HIFs in transmission lines is accomplished using the characteristics of a ZnO arrester, which is then implemented within the overall transmission system model based on the electromagnetic transients programme. This paper proposes an algorithm for fault detection and classification for both LIFs and HIFs using Adaptive Network-based Fuzzy Inference System (ANFIS). The inputs into ANFIS are current signals only based on Root-Mean-Square values of three-phase currents and zero sequence current. The performance of the proposed algorithm is tested on a typical 154 kV Korean transmission line system under various fault conditions. Test results show that the ANFIS can detect and classify faults including (LIFs and HIFs) accurately within half a cycle. (C) 2003 Elsevier Science Ltd. All rights reserved
Abstract: Accurate detection and classification of faults on transmission lines is vitally important. In this respect, many different types of faults occur, inter alia low impedance faults (LIF) and high impedance faults (HIF). The latter in particular pose difficulties for the commonly employed conventional overcurrent and distance relays, and if not detected, can cause damage to expensive equipment, threaten life and cause fire hazards. Although HIFs are far less common than LIFs, it is imperative that any protection device should be able to satisfactorily deal with both HIFs and LIFs. Because of the randomness and asymmetric characteristics of HIFs, the modelling of HIF is difficult and many papers relating to various HIF models have been published. In this paper, the model of HIFs in transmission lines is accomplished using the characteristics of a ZnO arrester, which is then implemented within the overall transmission system model based on the electromagnetic transients programme. This paper proposes an algorithm for fault detection and classification for both LIFs and HIFs using Adaptive Network-based Fuzzy Inference System (ANFIS). The inputs into ANFIS are current signals only based on Root-Mean-Square values of three-phase currents and zero sequence current. The performance of the proposed algorithm is tested on a typical 154 kV Korean transmission line system under various fault conditions. Test results show that the ANFIS can detect and classify faults including (LIFs and HIFs) accurately within half a cycle. (C) 2003 Elsevier Science Ltd. All rights reserved
100. 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
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
101. 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
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
102. 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
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
103. 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
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
104. Sanaye-Pasand, M., 2003. Discussion of "A novel approach using a FIRANN for fault detection and direction estimation for high voltage transmission lines". Ieee Transactions on Power Delivery 18, 644.
105. Orille, A.L., Khalil, N., 2003. Closure on "A novel approach using a firann for fault detection and direction estimation for high-voltage transmission lines". Ieee Transactions on Power Delivery 18, 644-645.
106. 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.
107. 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.
108. 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)
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)
109. 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
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
111. 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
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
112. 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
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
113. 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
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
114. Sanaye-Pasand, M., Malik, O.P., 2001. Neural network-based fault direction discrimination for high-speed transmission line protection. Electric Power Components and Systems 29, 757-770.
Abstract: Detection of the direction of a fault on a transmission line is essential to the proper performance of a pourer system. With the advent of large generating stations and highly interconnected power systems, shorter fault clearing times are becoming necessary. To classify forward and backward faults on a given line rapidly, a neural networks abilities in pattern recognition and classification could be considered as a solution. To demonstrate the applicability of this solution, neural network technique is employed to design two different fault direction discrimination modules. Results of performance studies with the proposed networks are presented in this paper. Results obtained indicate that the direction of fault on a transmission line can be identified rapidly and correctly by the proposed approaches
Abstract: Detection of the direction of a fault on a transmission line is essential to the proper performance of a pourer system. With the advent of large generating stations and highly interconnected power systems, shorter fault clearing times are becoming necessary. To classify forward and backward faults on a given line rapidly, a neural networks abilities in pattern recognition and classification could be considered as a solution. To demonstrate the applicability of this solution, neural network technique is employed to design two different fault direction discrimination modules. Results of performance studies with the proposed networks are presented in this paper. Results obtained indicate that the direction of fault on a transmission line can be identified rapidly and correctly by the proposed approaches
116. 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
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
117. 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
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
118. Lee, J.B., Jung, C.H., Kim, I.D., Baek, Y.K., 2000. Protective relay testing and characteristic analysis for high impedance faults in transmission lines. Electric Power Systems Research 56, 129-137.
Abstract: This paper describes the relay testing method and the results for detecting availability of protective relays under high impedance faults (HIFs) in transmission fines. Mho type distance relays, quadrilateral type distance relays and PCM type current differential relays are selected for relay testing. Four kinds of model power systems including actual power systems to be used for relay testing are established in PSCAD/EMTDC. Each protective relay is tested using RTDS and RTPS. The boundaries of each operating zone are surveyed by testing. Availability of HIFs detection on each relay are compared to each other. Impedance variation characteristics at the relay point are investigated using EMTDC in the case that source zero sequence impedance and load impedance are varied, The results shown in this paper can be used as an effective reference to install protective relays in real power systems. (C) 2000 Elsevier Science S.A. All rights reserved
Abstract: This paper describes the relay testing method and the results for detecting availability of protective relays under high impedance faults (HIFs) in transmission fines. Mho type distance relays, quadrilateral type distance relays and PCM type current differential relays are selected for relay testing. Four kinds of model power systems including actual power systems to be used for relay testing are established in PSCAD/EMTDC. Each protective relay is tested using RTDS and RTPS. The boundaries of each operating zone are surveyed by testing. Availability of HIFs detection on each relay are compared to each other. Impedance variation characteristics at the relay point are investigated using EMTDC in the case that source zero sequence impedance and load impedance are varied, The results shown in this paper can be used as an effective reference to install protective relays in real power systems. (C) 2000 Elsevier Science S.A. All rights reserved
119. Williams, W.J., Zalubas, E.J., 2000. Helicopter transmission fault detection via time-frequency, scale and spectral methods. Mechanical Systems and Signal Processing 14, 545-559.
Abstract: The vast majority of the powerful and effective algorithms in signal processing start with the assumption of stationarity. In addition, the deterministic portion of the signal is often assumed to be composed of complex exponentials which are the solutions to linear time-invariant (LTI) differential equations. Many signals do not comply with these assumptions, however, resulting in disappointment when conventional techniques are used. We now have at hand time-frequency (t-f) and scale transform analyses which can provide new insights into the nature of non-stationary signals. This paper describes some results using reduced interference distributions (RIDs) and scale transforms in the analysis of signals obtained from accelerometers placed strategically on a Westland helicopter transmission. Fault detection algorithms for several types of faults were compared and the methods based on the scale transform performed best followed by RID results. More conventional spectral-analysis-based methods were the least effective. (C) 2000 Academic Press
Abstract: The vast majority of the powerful and effective algorithms in signal processing start with the assumption of stationarity. In addition, the deterministic portion of the signal is often assumed to be composed of complex exponentials which are the solutions to linear time-invariant (LTI) differential equations. Many signals do not comply with these assumptions, however, resulting in disappointment when conventional techniques are used. We now have at hand time-frequency (t-f) and scale transform analyses which can provide new insights into the nature of non-stationary signals. This paper describes some results using reduced interference distributions (RIDs) and scale transforms in the analysis of signals obtained from accelerometers placed strategically on a Westland helicopter transmission. Fault detection algorithms for several types of faults were compared and the methods based on the scale transform performed best followed by RID results. More conventional spectral-analysis-based methods were the least effective. (C) 2000 Academic Press
120. 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
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
121. Orille, A.L., Khalil, N., 1999. A fast faulted phase detection relay for high voltage transmission lines using the fir neural networks. Computers & Industrial Engineering 37, 395-398.
Abstract: This paper presents a new approach to on line faulted phase detection relay for high-speed protection of high voltage transmission lines using artificial neural networks. The phase detector shows its effectiveness using one relay connected to a transmission line of a transmission circuit, which is composed of three phase 400 kV transmission lines. The type of the neural network used in this approach is the Finite Impulse Response Artificial Neural Network (FIRANN). The FIRANN is trained using temporal backpropagation training algorithm. The training patterns are obtained by simulating different fault types, fault locations and loads for a certain power network using the ATP (Alternative Transient Program) version of the EMTP (Electro-Magnetic Transient Program). Also, dynamic are faults and current transformer saturation had been taken into account. This type of neural networks shows a very great insensibility against lost and bad data and post-fault and pre-fault noise. (C) 1999 Elsevier Science Ltd. All rights reserved
Abstract: This paper presents a new approach to on line faulted phase detection relay for high-speed protection of high voltage transmission lines using artificial neural networks. The phase detector shows its effectiveness using one relay connected to a transmission line of a transmission circuit, which is composed of three phase 400 kV transmission lines. The type of the neural network used in this approach is the Finite Impulse Response Artificial Neural Network (FIRANN). The FIRANN is trained using temporal backpropagation training algorithm. The training patterns are obtained by simulating different fault types, fault locations and loads for a certain power network using the ATP (Alternative Transient Program) version of the EMTP (Electro-Magnetic Transient Program). Also, dynamic are faults and current transformer saturation had been taken into account. This type of neural networks shows a very great insensibility against lost and bad data and post-fault and pre-fault noise. (C) 1999 Elsevier Science Ltd. All rights reserved
122. Djuric, M.B., Radojevic, Z.M., Terzija, V.V., 1998. Arcing faults detection on transmission lines using least error squares technique. European Transactions on Electrical Power 8, 437-443.
Abstract: In this paper a new numerical algorithm for arcing faults detection and fault distance calculation is presented. The solution is given in the rime domain and for the most frequent single-phase to ground fault. it was derived by processing the line terminal voltages and currents. The new algorithm can be utilized for blocking the automatic reclosing. A simple square wave are voltage model was assumed to represent the long are in free air: The unknown model parameters (the line resistance and inductance, and arc voltage amplitude) were estimated by using "Least Error Squares Technique". The new algorithm was successfully tested by computer-simulated and laboratory tests
Abstract: In this paper a new numerical algorithm for arcing faults detection and fault distance calculation is presented. The solution is given in the rime domain and for the most frequent single-phase to ground fault. it was derived by processing the line terminal voltages and currents. The new algorithm can be utilized for blocking the automatic reclosing. A simple square wave are voltage model was assumed to represent the long are in free air: The unknown model parameters (the line resistance and inductance, and arc voltage amplitude) were estimated by using "Least Error Squares Technique". The new algorithm was successfully tested by computer-simulated and laboratory tests
123. 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
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
124. Sanaye-Pasand, M., Malik, O.P., 1998. High speed transmission system directional protection using an Elman network. Ieee Transactions on Power Delivery 13, 1040-1045.
Abstract: Detection of the direction of a fault on a transmission line is essential to the proper performance of a power system. It would be desirable to develop a high speed and accurate approach to determine the fault direction far different pourer system conditions. To classify forward and backward faults on a given line, neural network's abilities in pattern recognition and classification could be considered as a solution. To demonstrate the applicability of this solution, neural network technique is employed and a novel Elman recurrent net work is designed and trained. Details of the design procedure and the results of performance studies with the proposed network are given and analysed in the paper. System simulation studies show that the proposed approach is able to detect the direction of a fault on a transmission line rapidly and correctly. It is suitable to realize a very fast transmission line directional comparison protection scheme
Abstract: Detection of the direction of a fault on a transmission line is essential to the proper performance of a power system. It would be desirable to develop a high speed and accurate approach to determine the fault direction far different pourer system conditions. To classify forward and backward faults on a given line, neural network's abilities in pattern recognition and classification could be considered as a solution. To demonstrate the applicability of this solution, neural network technique is employed and a novel Elman recurrent net work is designed and trained. Details of the design procedure and the results of performance studies with the proposed network are given and analysed in the paper. System simulation studies show that the proposed approach is able to detect the direction of a fault on a transmission line rapidly and correctly. It is suitable to realize a very fast transmission line directional comparison protection scheme
125. Bo, Z.Q., 1998. A new non-communication protection technique for transmission lines. Ieee Transactions on Power Delivery 13, 1073-1078.
Abstract: This paper proposes a new non-communication protection technique for transmission lines. The technique relies on firstly detection of fault generated high frequency current transient signals. A specially designed multi-channel filter unit is then applied to the captured signals to extract desired bands of high frequency signals. Comparison between the spectral energies of different bands of the filter outputs determines whether a fault is internal or external to the protected zone. in addition to the saving in costs through negating the need for a communication link, the technique also retains many advantages of the 'transient based protection' technology, such as insensitivity to fault type, fault position, fault path resistance and fault inception angle. It is also not affected by CT saturation, the power frequency short-circuit level at the terminating busbar or the precise configuration of the source side networks
Abstract: This paper proposes a new non-communication protection technique for transmission lines. The technique relies on firstly detection of fault generated high frequency current transient signals. A specially designed multi-channel filter unit is then applied to the captured signals to extract desired bands of high frequency signals. Comparison between the spectral energies of different bands of the filter outputs determines whether a fault is internal or external to the protected zone. in addition to the saving in costs through negating the need for a communication link, the technique also retains many advantages of the 'transient based protection' technology, such as insensitivity to fault type, fault position, fault path resistance and fault inception angle. It is also not affected by CT saturation, the power frequency short-circuit level at the terminating busbar or the precise configuration of the source side networks
126. Wang, H.S., Keerthipala, W.W.L., 1998. Fuzzy-neuro approach to fault classification for transmission line protection. Ieee Transactions on Power Delivery 13, 1093-1104.
Abstract: This paper presents a new approach to real-time fault detection and classification in power transmission systems by using fuzzy-neuro techniques. The integration with neural network technology enhances fuzzy logic systems on learning capabilities. The symmetrical components in combination with three line currents are utilized to detect fault types such as single line-to ground, line-to-line, double line-to-ground and three line-to-ground, and then to define the faulty Line. Computer simulation results are shown in this paper and they indicate this approach can be used as an effective tool for high speed digital relaying, as the correct detection is achieved in less than 10ms
Abstract: This paper presents a new approach to real-time fault detection and classification in power transmission systems by using fuzzy-neuro techniques. The integration with neural network technology enhances fuzzy logic systems on learning capabilities. The symmetrical components in combination with three line currents are utilized to detect fault types such as single line-to ground, line-to-line, double line-to-ground and three line-to-ground, and then to define the faulty Line. Computer simulation results are shown in this paper and they indicate this approach can be used as an effective tool for high speed digital relaying, as the correct detection is achieved in less than 10ms
127. Chowdhury, F.N., Aravena, J.L., 1998. A modular methodology for fast fault detection and classification in power systems. Ieee Transactions on Control Systems Technology 6, 623-634.
Abstract: This paper presents a modular yet integrated approach to the problem of fast fault detection and classification. Although the specific application example studied here is a power system, the method would be applicable to arbitrary dynamic systems. The approach is quite flexible in the sense that it can be model-based or model-free. In the model-free case, we emphasize the use of concepts from signal processing and wavelet theory to create fast and sensitive fault indicators. If a model is available then conventionally generated residuals can serve as fault indicators, The indicators can then be analyzed by standard statistical hypothesis testing or by artificial neural networks to create intelligent decision rules. After a detection, the fault indicator is processed by a Kohonen network to classify the fault. The approach described here is expected to be of wide applicability. Results of computer experiments with simulated faulty transmission lines are included
Abstract: This paper presents a modular yet integrated approach to the problem of fast fault detection and classification. Although the specific application example studied here is a power system, the method would be applicable to arbitrary dynamic systems. The approach is quite flexible in the sense that it can be model-based or model-free. In the model-free case, we emphasize the use of concepts from signal processing and wavelet theory to create fast and sensitive fault indicators. If a model is available then conventionally generated residuals can serve as fault indicators, The indicators can then be analyzed by standard statistical hypothesis testing or by artificial neural networks to create intelligent decision rules. After a detection, the fault indicator is processed by a Kohonen network to classify the fault. The approach described here is expected to be of wide applicability. Results of computer experiments with simulated faulty transmission lines are included
128. Nikawa, K., Inoue, S., 1998. Highly sensitive OBIRCH system for fault localization and defect detection. Ieice Transactions on Information and Systems E81D, 743-748.
Abstract: We have improved the optical beam induced resistance change (OBIRCH) system so as to detect(1) a current path as small as 10-50 mu A from the rear side of a chip, (2) current paths in silicide lines as narrow as 0.2 mu m, (3) high-resistance Ti-depleted polysilicon regions in 0.2 mu m wide silicide lines, and (4) high-resistance amorphous thin layers as thin as a few nanometers at the bottoms of vias. All detections were possible even in observation areas as wide as 5 mm x 5 mm. The physical causes of these detections were characterized by focused ion beam and transmission electron microscopy
Abstract: We have improved the optical beam induced resistance change (OBIRCH) system so as to detect(1) a current path as small as 10-50 mu A from the rear side of a chip, (2) current paths in silicide lines as narrow as 0.2 mu m, (3) high-resistance Ti-depleted polysilicon regions in 0.2 mu m wide silicide lines, and (4) high-resistance amorphous thin layers as thin as a few nanometers at the bottoms of vias. All detections were possible even in observation areas as wide as 5 mm x 5 mm. The physical causes of these detections were characterized by focused ion beam and transmission electron microscopy
129. Liang, J., Elangovan, S., Devotta, J.B.X., 1998. A wavelet multiresolution analysis approach to fault detection and classification in transmission lines. International Journal of Electrical Power & Energy Systems 20, 327-332.
Abstract: A real-time wavelet multiresolution analysis (MRA)-based fault detection and classification algorithm is proposed in this paper. The first stage MRA detail signals extracted from the original signals are used as the criteria for this problem. By measuring the sharp variation values of the MRA detail signals, faults in the power system can be detected The fault type is then identified by the comparison of the three-phase MRA sharp variations. The effects of the fault distance, fault inception angle and fault impedance are examined, and the fault classification routine is designed to overcome their effects. Simulation results show that this algorithm is effective and robust, and it is promising in high impedance fault detection. (C) 1998 Elsevier Science Ltd. All rights reserved
Abstract: A real-time wavelet multiresolution analysis (MRA)-based fault detection and classification algorithm is proposed in this paper. The first stage MRA detail signals extracted from the original signals are used as the criteria for this problem. By measuring the sharp variation values of the MRA detail signals, faults in the power system can be detected The fault type is then identified by the comparison of the three-phase MRA sharp variations. The effects of the fault distance, fault inception angle and fault impedance are examined, and the fault classification routine is designed to overcome their effects. Simulation results show that this algorithm is effective and robust, and it is promising in high impedance fault detection. (C) 1998 Elsevier Science Ltd. All rights reserved
130. Saleh, K., Al-Saqabi, K., 1998. Error detection and diagnosis for fault tolerance in distributed systems. Information and Software Technology 39, 975-983.
Abstract: The early error detection and the understanding of the nature and conditions of an error occurrence can be useful to make an effective and efficient recovery in distributed systems. Various distributed system extensions were introduced for the implementation of fault tolerance in distributed software systems. These extensions rely mainly on the exchange of contextual information appended to every transmitted application specific message. Ideally, this information should be used for checkpointing, error detection, diagnosis and recovery should a transient failure occur later during the distributed program execution. In this paper, we present a generalized extension suitable for fault-tolerant distributed systems such as communication software systems and its detection capabilities are shown. Our extension is based on the execution of message validity test prior to the transmission of messages and the piggybacking of contextual information to facilitate the detection and diagnosis of transient faults in the distributed system. (C) 1998 Elsevier Science B.V
Abstract: The early error detection and the understanding of the nature and conditions of an error occurrence can be useful to make an effective and efficient recovery in distributed systems. Various distributed system extensions were introduced for the implementation of fault tolerance in distributed software systems. These extensions rely mainly on the exchange of contextual information appended to every transmitted application specific message. Ideally, this information should be used for checkpointing, error detection, diagnosis and recovery should a transient failure occur later during the distributed program execution. In this paper, we present a generalized extension suitable for fault-tolerant distributed systems such as communication software systems and its detection capabilities are shown. Our extension is based on the execution of message validity test prior to the transmission of messages and the piggybacking of contextual information to facilitate the detection and diagnosis of transient faults in the distributed system. (C) 1998 Elsevier Science B.V
131. Djuric, M.B., Radojevic, Z.M., Terzija, V.V., 1997. Numerical algorithm for arcing faults detection and fault distance calculation on overhead lines. Electric Machines and Power Systems 25, 939-953.
Abstract: In this paper a new numerical algorithm for arcing faults detection and fault distance calculation will be presented. It provides the solution for both the symmetrical and the unsymmetrical faults. The algorithm is based on the line terminal voltages and currents processing. A simple square wave are voltage model is assumed to model the long are in free air in computer simulation and algorithm development. The frequency dependence of line parameters is taken into account. A series of computer simulated and laboratory tests have shown that the new algorithm can be utilized in transmission system practice
Abstract: In this paper a new numerical algorithm for arcing faults detection and fault distance calculation will be presented. It provides the solution for both the symmetrical and the unsymmetrical faults. The algorithm is based on the line terminal voltages and currents processing. A simple square wave are voltage model is assumed to model the long are in free air in computer simulation and algorithm development. The frequency dependence of line parameters is taken into account. A series of computer simulated and laboratory tests have shown that the new algorithm can be utilized in transmission system practice
132. Song, Y.H., Xuan, Q.X., Johns, A.T., 1997. Comparison studies of five neural network based fault classifiers for complex transmission lines. Electric Power Systems Research 43, 125-132.
Abstract: The application of neural networks to power systems has been extensively reported. In the field of protection, neural network based protection techniques have been proposed by a number of investigators including the authors. However, almost all the studies have so far employed the back-propagation neural network structure with supervised learning. It is the purpose of this paper to report some recent studies on different neural network models, particularly those with combined supervised/unsupervised learning applied to fault classification for complex transmission lines. The neural networks concerned here include: (i) back-propagation net; (ii) feature-map net; (iii) radial basis function net; (iv) counter-propagation net and (v) learning vector quantization net. Special emphasis is placed on a comparison of the performance of the five neural networks in terms of size of the neural network, learning process, classification accuracy and robustness. The outcome of the work serves and provides guidelines on how to select a particular neural network from a number of different neural networks for a specific application. (C) 1997 Elsevier Science S.A
Abstract: The application of neural networks to power systems has been extensively reported. In the field of protection, neural network based protection techniques have been proposed by a number of investigators including the authors. However, almost all the studies have so far employed the back-propagation neural network structure with supervised learning. It is the purpose of this paper to report some recent studies on different neural network models, particularly those with combined supervised/unsupervised learning applied to fault classification for complex transmission lines. The neural networks concerned here include: (i) back-propagation net; (ii) feature-map net; (iii) radial basis function net; (iv) counter-propagation net and (v) learning vector quantization net. Special emphasis is placed on a comparison of the performance of the five neural networks in terms of size of the neural network, learning process, classification accuracy and robustness. The outcome of the work serves and provides guidelines on how to select a particular neural network from a number of different neural networks for a specific application. (C) 1997 Elsevier Science S.A
133. Sharaf, A.M., ElSharkawy, R.M., Talaat, H.E.A., Badr, M.A.L., 1997. Fault detection on radial and meshed transmission systems using fast Hilbert transform. Electric Power Systems Research 41, 185-190.
Abstract: This paper presents two simple fault detection schemes for radial and meshed transmission systems based on Fast Hilbert transformations of voltage and current signals at the substation terminal. The novel schemes ensure detection accuracy, selectivity and distinction between the two fault types as a boiled/fixed impedance or a high impedance non-linear fault. (C) 1997 Elsevier Science S.A
Abstract: This paper presents two simple fault detection schemes for radial and meshed transmission systems based on Fast Hilbert transformations of voltage and current signals at the substation terminal. The novel schemes ensure detection accuracy, selectivity and distinction between the two fault types as a boiled/fixed impedance or a high impedance non-linear fault. (C) 1997 Elsevier Science S.A
134. Demcko, J.A., Pillutla, S., Keyhani, A., 1996. Measurement of synchronous generator data from digital fault recorders for tracking of parameters and field degradation detection. Electric Power Systems Research 39, 205-213.
Abstract: This paper presents a description of advanced instrumentation technology developed at Arizona Public Service (APS) for on-line monitoring of large turbogenerators. These signals include three-phase generator voltages and currents, generator held winding voltages and currents, generator power angle and turbine front standard speed deviation. The data is collected by a 16 analog channel 10 bit digital fault recorder (DFR) for several operating conditions including steady state, transient events due to transmission line faults, etc., and staged tests. The paper also discusses the methodology behind the use of these measured signals for on-line tracking of the stability parameters of a synchronous generator. In this context, a procedure for the on-line estimation of machine parameters and turns ratios will be developed. Continuous monitoring of the machine parameters and turns ratios in real time may then be used for incipient failure detection. (C) 1996 Elsevier Science S.A
Abstract: This paper presents a description of advanced instrumentation technology developed at Arizona Public Service (APS) for on-line monitoring of large turbogenerators. These signals include three-phase generator voltages and currents, generator held winding voltages and currents, generator power angle and turbine front standard speed deviation. The data is collected by a 16 analog channel 10 bit digital fault recorder (DFR) for several operating conditions including steady state, transient events due to transmission line faults, etc., and staged tests. The paper also discusses the methodology behind the use of these measured signals for on-line tracking of the stability parameters of a synchronous generator. In this context, a procedure for the on-line estimation of machine parameters and turns ratios will be developed. Continuous monitoring of the machine parameters and turns ratios in real time may then be used for incipient failure detection. (C) 1996 Elsevier Science S.A
135. Lai, L.L., NdehChe, F., Chu, K.H., Yokoyama, R., Zhao, M., 1997. A new application of ferrite and high-frequency signals to power system protection. European Transactions on Electrical Power 7, 35-39.
Abstract: This paper reports a new scheme where ferrite materials and high-frequency signals are used to detect power system faults. The ferrite acts as a broad band dissipater. The attenuation properties of ferrite beads on high-frequency signals is studied and are then used on a 10 m long single-phase transmission line model to investigate their use as a primary detection device in a non-unit protection scheme which possesses unit protection properties. The results show that the ferrite beads attenuate the high-frequency noise quite effectively. But the picking up of high-frequency noise has to be considered as well
Abstract: This paper reports a new scheme where ferrite materials and high-frequency signals are used to detect power system faults. The ferrite acts as a broad band dissipater. The attenuation properties of ferrite beads on high-frequency signals is studied and are then used on a 10 m long single-phase transmission line model to investigate their use as a primary detection device in a non-unit protection scheme which possesses unit protection properties. The results show that the ferrite beads attenuate the high-frequency noise quite effectively. But the picking up of high-frequency noise has to be considered as well
136. Djuric, M.B., Radojevic, Z.M., Terzija, V.V., 1997. Digital signal processing algorithm for arcing faults detection and fault distance calculation on transmission lines. International Journal of Electrical Power & Energy Systems 19, 165-170.
Abstract: In this paper a new digital signal processing algorithm for arcing fault detection and fault distance calculation is presented Tt was derived by processing the line terminal voltages and currents. A simple square wave are voltage model was assumed to represent the long are in free air. The unknown model parameters (the line resistance and inductance, and are voltage amplitude) were estimated by using the least squares error technique. The new algorithm was successfully tested by computer simulated and laboratory tests. (C) 1997 Elsevier Science Ltd
Abstract: In this paper a new digital signal processing algorithm for arcing fault detection and fault distance calculation is presented Tt was derived by processing the line terminal voltages and currents. A simple square wave are voltage model was assumed to represent the long are in free air. The unknown model parameters (the line resistance and inductance, and are voltage amplitude) were estimated by using the least squares error technique. The new algorithm was successfully tested by computer simulated and laboratory tests. (C) 1997 Elsevier Science Ltd
138. Chowdhury, B.H., Wang, K.Y., 1996. Fault classification in power systems using artificial neural networks. Engineering Intelligent Systems for Electrical Engineering and Communications 4, 101-112.
Abstract: Recent applications of neural networks to power system fault diagnosis have provided positive results and shown advantages in process speed over conventional approaches. This paper describes the application of a Kohonen neural network and the backpropagation network to fault detection and classification using the fundamental components of currents and voltages. The Kohonen network is selected for its excellent pattern classification capability while the backpropagation method is chosen for comparison since it is the most commonly used ANN scheme. The Electromagnetic Transients Program is used to obtain fault patterns for the training and testing of neural networks. Accurate classifications are obtained for all types of possible short circuit faults on test systems representing high voltage transmission lines. Shorter training time makes the Kohonen network more suitable for power system fault diagnosis. The method introduced in the paper can be easily extended to any size power system since the only information required for the NN to function are those that are recorded at substation fault recorders. With fast NN hardware now becoming available, on-line implementation is only a question of economics
Abstract: Recent applications of neural networks to power system fault diagnosis have provided positive results and shown advantages in process speed over conventional approaches. This paper describes the application of a Kohonen neural network and the backpropagation network to fault detection and classification using the fundamental components of currents and voltages. The Kohonen network is selected for its excellent pattern classification capability while the backpropagation method is chosen for comparison since it is the most commonly used ANN scheme. The Electromagnetic Transients Program is used to obtain fault patterns for the training and testing of neural networks. Accurate classifications are obtained for all types of possible short circuit faults on test systems representing high voltage transmission lines. Shorter training time makes the Kohonen network more suitable for power system fault diagnosis. The method introduced in the paper can be easily extended to any size power system since the only information required for the NN to function are those that are recorded at substation fault recorders. With fast NN hardware now becoming available, on-line implementation is only a question of economics
139. Dawson, S., Jahanian, F., 1995. Deterministic fault injection of distributed systems. Theory and Practice in Distributed Systems 938, 178-196.
Abstract: Ensuring that a system meets its prescribed specification is a growing challenge that confronts software developers and system engineers. Meeting this challenge is particularly important for distributed systems with strict dependability and timeliness constraints. This paper presents a technique, called script-driven probing and fault injection, for the evaluation and validation of dependable protocols. The proposed approach can be used to demonstrate three aspects of a target protocol: i) detection of design or implementation errors, ii) identification of violations of protocol specifications, and iii) insight into design decisions made by the implementers. To demonstrate the capabilities of this technique, the paper briefly describes a probing and fault injection tool called the PFI tool, and several experiments on two protocols: the Transmission Control Protocol (TCP) [4, 24] and the Group Membership Protocol (GMP) [19]. The tool can be used to delay, drop, reorder, duplicate, and modify messages. It can also introduce new messages into the system to probe participants. In the case of TCP, we used the PFI tool to duplicate the experiments reported in [7] on several TCP implementations without access to the vendors' TCP source code in a very short time. We also ran several new experiments that are difficult to perform using past approaches based on packet monitoring and filtering. In the case of GMP, we used the tool to test the fault-tolerance capabilities of an implementation under various failure models including daemon/link crash, send/receive omissions, and timing failures. Furthermore, by selective reordering of messages and spontaneous transmission of new messages, we were able to guide a distributed computation into hard to reach global states without instrumenting the protocol implementation
Abstract: Ensuring that a system meets its prescribed specification is a growing challenge that confronts software developers and system engineers. Meeting this challenge is particularly important for distributed systems with strict dependability and timeliness constraints. This paper presents a technique, called script-driven probing and fault injection, for the evaluation and validation of dependable protocols. The proposed approach can be used to demonstrate three aspects of a target protocol: i) detection of design or implementation errors, ii) identification of violations of protocol specifications, and iii) insight into design decisions made by the implementers. To demonstrate the capabilities of this technique, the paper briefly describes a probing and fault injection tool called the PFI tool, and several experiments on two protocols: the Transmission Control Protocol (TCP) [4, 24] and the Group Membership Protocol (GMP) [19]. The tool can be used to delay, drop, reorder, duplicate, and modify messages. It can also introduce new messages into the system to probe participants. In the case of TCP, we used the PFI tool to duplicate the experiments reported in [7] on several TCP implementations without access to the vendors' TCP source code in a very short time. We also ran several new experiments that are difficult to perform using past approaches based on packet monitoring and filtering. In the case of GMP, we used the tool to test the fault-tolerance capabilities of an implementation under various failure models including daemon/link crash, send/receive omissions, and timing failures. Furthermore, by selective reordering of messages and spontaneous transmission of new messages, we were able to guide a distributed computation into hard to reach global states without instrumenting the protocol implementation
140. 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
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
141. Barros, J., Drake, J.M., 1994. Realtime Fault-Detection and Classification in Power-Systems Using Microprocessors. Iee Proceedings-Generation Transmission and Distribution 141, 315-322.
Abstract: A method is proposed for real-time fault detection and classification in power systems. The method can be implemented in low-cost units based on 8-bit microprocessors. These units are part of a multiprocessor system which allows the detection of single line to ground faults, double line and double line to ground faults, and three-phase faults. The detection of an overcurrent triggers two simultaneous processes executed in real time: the waveforms of the voltage and current signals are registered and a probabilistic criterion is used for fault confirmation. The process of confirmation is based on the estimation of the three phase voltage phasors by means of a set of Kalman filters, and on the calculation of the fault probability. If the fault has been classified correctly, a recording is made with the samples acquired, including five cycles of the prefault signals and 150 cycles of the postfault signals. This recording is use by the multiprocessor system to calculate the fault distance and to generate an accurate fault recording. The algorithm has been verified using a computer simulation of the different types of faults, and has been optimised so as to detect and correctly classify faults in less than 20 ms
Abstract: A method is proposed for real-time fault detection and classification in power systems. The method can be implemented in low-cost units based on 8-bit microprocessors. These units are part of a multiprocessor system which allows the detection of single line to ground faults, double line and double line to ground faults, and three-phase faults. The detection of an overcurrent triggers two simultaneous processes executed in real time: the waveforms of the voltage and current signals are registered and a probabilistic criterion is used for fault confirmation. The process of confirmation is based on the estimation of the three phase voltage phasors by means of a set of Kalman filters, and on the calculation of the fault probability. If the fault has been classified correctly, a recording is made with the samples acquired, including five cycles of the prefault signals and 150 cycles of the postfault signals. This recording is use by the multiprocessor system to calculate the fault distance and to generate an accurate fault recording. The algorithm has been verified using a computer simulation of the different types of faults, and has been optimised so as to detect and correctly classify faults in less than 20 ms
142. Agrawal, P., Aggarwal, R.K., 1992. Theoretical Concept and Digital-Simulation of the Pramod Scheme for Uhs Protection of Ehv Transmission-Lines. Ieee Transactions on Power Delivery 7, 1104-1111.
Abstract: This paper describes the theoretical concept of the Pramod scheme for ultra high speed (UHS) protection of the EHV transmission lines. The principle is based on detection of the fault induced high frequency signals of the order of kilo Hertz. A technique for the digital simulation of the transmission line and the high frequency detecting circuit has been explained and the results have been presented
Abstract: This paper describes the theoretical concept of the Pramod scheme for ultra high speed (UHS) protection of the EHV transmission lines. The principle is based on detection of the fault induced high frequency signals of the order of kilo Hertz. A technique for the digital simulation of the transmission line and the high frequency detecting circuit has been explained and the results have been presented
143. Ramaswami, R., Mcguire, P.F., Prasad, M., 1992. Integrated Coordination and Short-Circuit Analysis for System Protection. Ieee Transactions on Power Delivery 7, 1112-1120.
Abstract: The operational demands placed on modern power transmission networks as well as their topological complexity make the task of the system protection engineer ever more difficult. The need for computer-based tools to assist with the evaluation and possible correction of relay settings is therefore more immediate. A coordinated set of data management and analysis programs, already in use at several major utilities in the USA, is presented. The primary focus here is on the so-called Coordination Graphics module. Both distance and overcurrent protective devices are treated. Realistic examples illustrate the detection of miscoordination. Corrective actions are taken using graphical manipulations (curve dragging) and direct specification of taps, test points, or desired reach
Abstract: The operational demands placed on modern power transmission networks as well as their topological complexity make the task of the system protection engineer ever more difficult. The need for computer-based tools to assist with the evaluation and possible correction of relay settings is therefore more immediate. A coordinated set of data management and analysis programs, already in use at several major utilities in the USA, is presented. The primary focus here is on the so-called Coordination Graphics module. Both distance and overcurrent protective devices are treated. Realistic examples illustrate the detection of miscoordination. Corrective actions are taken using graphical manipulations (curve dragging) and direct specification of taps, test points, or desired reach
144. Kumar, B.S.A., Ganesan, K., Rivera, E.F., Nelson, B.D., Malik, O.P., Desao, P., 1992. Envelope Compensation for High-Speed Digital Protection. Ieee Transactions on Power Delivery 7, 1139-1147.
Abstract: The time delay compensation method as presented in an earlier paper [3], attempts to reduce the delay introduced by different components of a relaying system. The method uses the transient fault signal, the prefault signal and a predetermined system time constant to estimate the postfault steady-state signal. While the results were encouraging from the viewpoint of delay reduction, a number of difficulties such as overreaching, singularity at the origin and oscillations were encountered. Amongst these, the overreach problem was severe enough to warrant a search for new methods. This paper reports the results of a variety of methods attempted for reducing the overreach problem. A better convergence function has been identified which gives faster fault detection without increased overreaching. Other problems mentioned above are also reduced by the new method. The method is verified using computed transients of a transmission line
Abstract: The time delay compensation method as presented in an earlier paper [3], attempts to reduce the delay introduced by different components of a relaying system. The method uses the transient fault signal, the prefault signal and a predetermined system time constant to estimate the postfault steady-state signal. While the results were encouraging from the viewpoint of delay reduction, a number of difficulties such as overreaching, singularity at the origin and oscillations were encountered. Amongst these, the overreach problem was severe enough to warrant a search for new methods. This paper reports the results of a variety of methods attempted for reducing the overreach problem. A better convergence function has been identified which gives faster fault detection without increased overreaching. Other problems mentioned above are also reduced by the new method. The method is verified using computed transients of a transmission line
145. Agrawal, P., Thomas, D.W.P., 1992. Digitally Simulated Test-Performance of the Pramod Scheme for Uhs Protection of Ehv Transmission-Lines. Ieee Transactions on Power Delivery 7, 1148-1155.
Abstract: This paper describes the digital simulation technique for the signal processing of the Pramod scheme and studies the digitally simulated test performance of the scheme for the satisfactory operation under different fault conditions. The Pramod scheme published some where else is based on the detection of high frequency voltage signals through stack tuners
Abstract: This paper describes the digital simulation technique for the signal processing of the Pramod scheme and studies the digitally simulated test performance of the scheme for the satisfactory operation under different fault conditions. The Pramod scheme published some where else is based on the detection of high frequency voltage signals through stack tuners
146. Katsuta, G., Muraoka, K., Inoue, N., Sakai, S., Tsunekage, T., Ando, K., 1992. Fault Section Detection System for 66-Kv Underground Branch Transmission-Lines Using Optical Magnetic-Field Sensors. Ieee Transactions on Power Delivery 7, 1-9.
Abstract: A fault section detection system, which uses optical magnetic field sensors and instantly detects the section in which a ground fault occurred, was developed for 66-kV underground multi-terminal systems having Y-branch joint boxes. The optical magnetic field sensor, which is based on Faraday effect in Bi-doped YIG ((BiYbGd)3Fe5O12) having a large verdet constant, detects cable conductor currents of 0 to 2000 A at high precision with the use of a laminated magnetic ring core of silicon steel plates. Sensors and a fault section detector/indicator of a system are connected with optical fibers capable of non-repeated transmission of over 6 km
Abstract: A fault section detection system, which uses optical magnetic field sensors and instantly detects the section in which a ground fault occurred, was developed for 66-kV underground multi-terminal systems having Y-branch joint boxes. The optical magnetic field sensor, which is based on Faraday effect in Bi-doped YIG ((BiYbGd)3Fe5O12) having a large verdet constant, detects cable conductor currents of 0 to 2000 A at high precision with the use of a laminated magnetic ring core of silicon steel plates. Sensors and a fault section detector/indicator of a system are connected with optical fibers capable of non-repeated transmission of over 6 km
147. 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
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
148. Wilson, R.E., 1991. Uses of Precise Time and Frequency in Power-Systems. Proceedings of the Ieee 79, 1009-1018.
Abstract: Accurately measured time and frequency plays an important role in the operation of modern electric power systems. A modern power system is a complicated and widely dispersed structure often covering a multistate or multiprovince area. Large numbers of generators and customer loads are operated in parallel. On an interconnected system composed of many control areas, the reliable transfer of electrical power from the point of generation to the consumer depends on measuring power system frequency in many locations. Because of the large amounts of electrical energy consumed in modern society, power is transmitted at high voltages. An elaborate protection and control system guards the high voltage equipment from short and open circuits. For the highest reliability of electric service, all control system operations need to be analyzed. Precise timekeeping networks aid in the analysis of power system operations by synchronizing the clocks on recording instruments. For dependable electrical service, all generators and large motors must remain close to speed synchronism and the voltage levels must remain near nominal values. The stable response of a power system to small and large perturbations is critical to continuity of electrical service. Research shows that measurement of the power system state vector can aid in the monitoring and control of system stability and voltage collapse. State vector measurement requires clock synchronizations of 5 to 46 microseconds. Knowledge of the location of a short circuit fault can speed the automatic or manual reenergizing of a transmission line. One fault location technique requires clocks synchronized to one microsecond. Research is now in progress to see if one microsecond timekeeping can aid and improve power system control and operation
Abstract: Accurately measured time and frequency plays an important role in the operation of modern electric power systems. A modern power system is a complicated and widely dispersed structure often covering a multistate or multiprovince area. Large numbers of generators and customer loads are operated in parallel. On an interconnected system composed of many control areas, the reliable transfer of electrical power from the point of generation to the consumer depends on measuring power system frequency in many locations. Because of the large amounts of electrical energy consumed in modern society, power is transmitted at high voltages. An elaborate protection and control system guards the high voltage equipment from short and open circuits. For the highest reliability of electric service, all control system operations need to be analyzed. Precise timekeeping networks aid in the analysis of power system operations by synchronizing the clocks on recording instruments. For dependable electrical service, all generators and large motors must remain close to speed synchronism and the voltage levels must remain near nominal values. The stable response of a power system to small and large perturbations is critical to continuity of electrical service. Research shows that measurement of the power system state vector can aid in the monitoring and control of system stability and voltage collapse. State vector measurement requires clock synchronizations of 5 to 46 microseconds. Knowledge of the location of a short circuit fault can speed the automatic or manual reenergizing of a transmission line. One fault location technique requires clocks synchronized to one microsecond. Research is now in progress to see if one microsecond timekeeping can aid and improve power system control and operation
149. 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
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
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