Ground relay, ground fault factor estimation method, program, and estimation standard generation method

摘要

PROBLEM TO BE SOLVED: To provide an apparatus and a method capable of estimating a ground fault factor in a consumer facility to be supplied with electric power by a distribution line with a simple configuration. A ground relay (12) includes a ground fault detection unit 113 that detects a ground fault in a consumer equipment 30 based on a zero-phase current, and a power system 90 and a consumer equipment when a ground fault is detected. Based on the timing at which the control unit 114 that opens the switch 11 between the switch and the ground fault detection unit 113 detects the ground fault, current data indicating the time change of the zero-phase current during the analysis period of a predetermined length is obtained. The current data extraction unit 121 to be extracted, the estimation unit 126 for estimating whether the cause of the ground fault is cable deterioration in the consumer equipment 30 or other factors based on the waveform of the current data, and the estimation unit 126 of the estimation unit 126. It includes an output unit 127 that outputs an estimation result. [Selection diagram] Fig. 3