To provide a fine ground fault detector which easily detect a fine ground fault which becomes a symptom before a ground fault accident occurs and which narrows down a location of the fine ground fault, and also to provide a method of detecting a fine ground fault.
A zero-phase current on a fine ground fault which occurs in the neutral point of a transformer 11 is detected and a zero-phase current on the fine ground fault which occurs in each of feeders 22a-22n is detected. In determining the feeders 22a-22n in which the current fine ground fault occurs from the detected zero-phase current of the feeders 22a-22n and determining the location of the current fine ground fault from the current waveform of the detected zero-phase current at the neutral point, a current waveform period is searched for the zero-phase current at the neutral point on the occurrence of the past fine ground fault equivalent to the current waveform period of the zero-phase current at the neutral point on the occurrence of the current fine ground fault to determine the location of the past fine ground fault of the detected equivalent period as the location of the current fine ground fault.
COPYRIGHT: (C)2010,JPO&INPIT
Masanao Hirosaki
Honma Koji
| JP2009186266A | ||||
| JP2001041995A | ||||
| JP7274384A | ||||
| JP2003284236A | ||||
| JP2005300205A |
Yoshiaki Naito
Hide Tanaka Tetsu