New method for transient line selection in distribution system based on grounding fault transferred

Abstract

When single-phase arc grounding fault occurs in the neutral ungrounded distribution system, the fault can be transferred by artificially grounding the faulty phase of the busbar, which can effectively improve the fault handling capability of distribution system. The theoretical analysis shows that the characteristic of transient zero-mode current is obviously different between grounding fault and fault transferred. That is to say, in the two grounding processes, the directions of the transient zero-mode current of the fault line are opposite and the direction of the transient zero-mode current of the non-fault line is identical. So, the fault line can be determined based on this theory. The zero-mode current of each line is analysed by wavelet packet decomposition, and the feature band is selected according to the point of maximum energy. The correlation coefficient polarity between two reconstructed data, each is extracted from the first quarter of power cycle of grounding process in respective feature band, is used to determine the criterion for fault line selection. This method only uses its own line information to choose fault line without any other line information. Simultaneously, number of simulation results shows that the method is accurate and reliable.