Power distribution network fault line selection method and system based on waveform similarity

The invention relates to a power distribution network fault line selection method and system based on waveform similarity, and belongs to the field of power system relay protection. When the bus zero sequence voltage instantaneous value exceeds the limit, fault line selection is started immediately; high-frequency transient pure fault components of the zero-sequence current of each feeder line and the zero-sequence voltage of the bus are obtained through calculation; the method comprises the following steps: according to a transient pure fault component of a bus zero-sequence voltage measured value and a feeder zero-sequence distributed capacitance parameter when a small current grounding system has a single-phase grounding fault, solving a virtual zero-sequence current waveform of each feeder on the premise of sequentially assuming that each feeder is a sound feeder; and performing Pearson correlation analysis on the actual measurement waveform of the zero-sequence current of each feeder line and the transie