METHOD FOR JUDGING FAULT POINT OF UNDERGROUND TRANSMISSION LINE

摘要

PROBLEM TO BE SOLVED: To provide a method for determining a ground fault wherein a rising point of ground current can be accurately obtained without a CT(current transformer) damaged due to the ground current which flows when an accident occurs. ;SOLUTION: A magnetic field sensor 6 is installed on a lead of an anti- corrosion layer protecting device 5 installed at a terminal connection 1 of a power cable 3 and an insulating cylinder 2 of IJ(insulation joint) 4 to detect ground surge current. Ground surge current waveforms detected by the magnetic field sensor 6 are combined by a tri-phase signal combiner 7 provided at each measurement point, converted by an E/O(electric/optical converter) 8 into an optic signal and transmitted via an optic fiber to a central processing unit 10. The central processing unit 10 compares rising points of ground surge waveforms optically transmitted from respective measurement points to determine where an accident occurs from their time difference or the like.;COPYRIGHT: (C)1998,JPO