Due to the complexity of fault states and the low accuracy for line selection in a resonant grounding system, a novel line selecting method of single-phase grounding fault for distribution network based on wavelet packet decomposition as well as signal distances is proposed in this paper. When a single-phase grounding fault occurs in a resonant grounding system, the transient zero sequence current is decomposed into multiple layers by wavelet packet, the lowest frequency band including power frequency is eliminated, and then the high frequency band decomposition coefficients are extracted. The high frequency decomposition coefficients are processed by signal distance algorithm, and a distance matrix can be obtained to select the faulty line. The results of simulation show that this method can give an accurate selection of the faulty line without the effects of initial phase angle, fault location, transition resistance as well as compensation states of arc suppression coil.

distribution system,faulty line selection,resonant grounding system,signal distance,wavelet packet