Friday, February 18, 2011

ABSTRAC, PROTECTION ON TRANSMISSION OVERHEAD LINE

1. Jamali, S., Ghaffarzadeh, N., 2010. A wavelet packet based method for adaptive single-pole auto-reclosing. Journal of Zhejiang University-Science C-Computers & Electronics 11, 1016-1024.

Abstract:
We present a new algorithm for adaptive single-pole auto-reclosing of power transmission lines using wavelet packet transform. The db8 wavelet packet decomposes the faulted phase voltage waveform to obtain the coefficients of the nodes 257, 259 to 262. An index is then defined from the sum of the energy coefficients of these nodes. By evaluating the index, transient and permanent faults, as well as the secondary arc extinction instant, can be identified. The significant advantage of the proposed algorithm is that it does not need a threshold level and therefore its performance is independent of fault location, line parameters, and operating conditions. Moreover, it can be used in transmission lines with reactor compensation. The proposed method has been successfully tested under a variety of fault conditions on a 400 kV overhead line of the Iranian National Grid using the Electro-Magnetic Transient Program (EMTP). The test results validated the algorithm's ability in distinguishing between transient arcing and permanent faults and determining the instant of secondary arc extinction

Saturday, February 12, 2011

ABSTRAC, HVDC PROTECTION

1. Yang, J., Fletcher, J.E., O'Reilly, J., 2010. Multiterminal DC Wind Farm Collection Grid Internal Fault Analysis and Protection Design. Ieee Transactions on Power Delivery 25, 2308-2318.
Abstract:
        The multiterminal dc wind farm is a promising topology with a voltage-source inverter (VSI) connection at the onshore grid. Voltage-source converters (VSCs) are robust to ac-side fault conditions. However, they are vulnerable to dc faults on the dc side of the converter. This paper analyzes dc faults, their transients, and the resulting protection issues. Overcurrent faults are analyzed in detail and provide an insight into protection system design. The radial wind farm topology with star or string connection is considered. The outcomes may be applicable for VSCs in the multi-VSC dc wind farm collection grid and VSC-based high-voltage direct current (HVDC) offshore transmission systems

Saturday, February 5, 2011

Particle Swarm Optimization

James Kennedy' and Russell Eberhart
Washington, DC 20212
kennedyjim @bls .gov
2Purdue School of Engineering and Technology
Indianapolis, IN 46202-5160
eberhart @ engr.iupui .edu
ABSTRACT
A concept for the optimization of nonlinear functions using particle swarm methodology is introduced.The evolution of several paradigms is outlined, and an implementation of one of the paradigms is  discussed. Benchmark testing of the paradigm is described, and applications, including nonlinear  function optimization and neural network training, are proposed. The relationships between particle  swarm optimization and both artificial life and genetic algorithms are described,