A NEW WAVELET PACKET ANALYSIS BASED METHOD TO DETECT FAULTY LINE FOR SINGLE PHASE TO GROUND FAULT OCCURRED IN DISTRIBUTION NETWORK WITH SMALL CURRENT NEUTRAL GROUNDING
SU Zhan-tao, LU Yan-ping (School of Electrical Engineering, Wuhan University, Wuhan 430072, Hubei Province, China)
Applying the wavelet packets to the decomposition of transient zero sequence current that appears after the single phase to ground fault occurred in the distribution network with small current neutral grounding, a new criterion based on waveform recognition is put forward, i.e., provided in a certain high frequency band of the fault current the majority of sampled points conform to the fault characteristics, so according to the principle that the minority is subordinate to the majority the fault line can be correctly detected. This method has high reliability, strong ability of anti-interference. This method needs not the on-site adjustment of the settings and is suitable to the distribution networks with different grounding modes.