Single-phase ground fault detection method suitable for neutral-point small-resistance grounding distribution network

The invention discloses a single-phase ground fault detection method suitable for a neutral-point small-resistance grounding distribution network. Based on the obvious difference between the ratio ofa differential value of the zero-sequence current to a differential value of the zero-sequence voltage in a faulty line and the counterpart ratio in a non-faulty line, zero-sequence voltage of a bus and zero-sequence current of a feeder line are collected to calculate the waveform similarity of the lines; then, whether a single-phase ground fault occurs in the lines or not is judged according to the waveform similarity, a faulty line and a non-faulty line can be correctly judged, the influence of transition resistance is small, and the method has good applicability to linear fault resistance and non-linear fault resistance and is not influenced by the polarity of a mutual inductor; moreover, the acquisition and processing of the zero-sequence voltage signal are added only on the basis of the traditional acquisitio