MEASURING METHOD OF LEAKAGE CURRENT OR RESISTANCE, ITS MONITORING APPARATUS AND ITS MONITORING SYSTEM

PROBLEM TO BE SOLVED: To easily calculate a resistance-portion current included in a leakage current. SOLUTION: In measurement of the resistance-portion current from a leakage current signal and a voltage signal from a current transformer in a circuit to be measured, a signal wave of at least one cycle of an alternating current is sampled, the average of an integrated value of the instantaneous value of a voltage and the instantaneous value of the leakage current is divided by the square root of the average of the squared each instantaneous value of the voltage. Since the highly reliable resistance-portion current and a resistance value can be measured and an insulation-deteriorated phase can be specified, inspection maintenance is enabled in advance by capturing the change of insulation deterioration with time and issuing an alarm, to thereby enable to prevent beforehand an accident. COPYRIGHT: (C)2003,JPO