DETECTION OF HIGH IMPEDANCE FAULTS IN MEDIUM VOLTAGE DISTRIBUTION NETWORKS USING DISCRETE WAVELET TRANSFORM

Detection and identification of high impedance faults in power networks are still a major challenge for protection engineers. In these cases, the fault current is so low that conventional protection devices are unable to detect it. A modeling study is developed to simulate the performance of the high impedance fault using MATLAB/Simulink program. Regarding the detection process, this paper uses the discrete wavelet transform as a powerful signal-processing tool. After performing five decompositions for the three phase current signals, we have extracted the detail, the wavelet output, to construct a detection criterion. The moving window approach is the technique used to obtain this criterion. Then, we have developed an algorithm for the detection issue. Two other algorithms are presented for the determination of faulted phase and feeder. (4 pages)