GROUNDING ACCIDENT DETECTOR AND GROUNDING ACCIDENT DETECTION METHOD

摘要

PPROBLEM TO BE SOLVED: To specify a section where a grounding accident is generated in a power transmission and distribution line with a large number of branched cables having a plurality of lines, by an inexpensive means. PSOLUTION: This grounding accident detector has current measuring means 61a, 61b, 61c for measuring currents IA, IB, IC flowing between a metal shielding layer in a usual connection part and the earth, a reference value holding means 62 for storing a grounding current reference value Iset, absolute value computing means 63a, 63b, 63c input with the currents IA, IB, IC, and for finding absolute values ¾IA-IB¾, ¾IB-IC¾, ¾IC=IA¾ of differences between the two currents out of them to be output, comparison-computing means 64a, 64b, 64c for comparing each of the absolute values ¾IA-IB¾, ¾IB-IC¾, ¾IC=IA¾ with the grounding current reference value Iset to output an ON-signal when equal or larger, in the each, and a logical sum computing means 65 input with outputs from the comparison-computing means to output a logical sum. PCOPYRIGHT: (C)2005,JPO&NCIPI