METHOD AND APPARATUS FOR MONITORING INSULATION DEGRADATION OF ELECTRIC ROTATING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a method in which a detection part is protected in the creepage of a lightning surge when a discharging pulse current is detected from a surge absorber, and in which the malfunction of an amplifier circuit due to the influence of a ringing is prevented. SOLUTION: In the method and the apparatus for the monitoring of the insulation degradation of an electric rotating machine, in the high-voltage winding of the electric rotating machine, the discharging pulse current flowing in the surge absorber connected to the high-voltage winding is detected, a signal which is synchronized with a detection signal from a detector which is arranged near the high-voltage winding and which detects only a partial discharge near the high-voltage winding is judged to be a partial discharge, and a partial discharge amount is evaluated on the basis of the discharging pulse current detected by a grounding conductor. It is not required to attach a coupling capacitor required only for a measurement, a measuring device is not burned and damaged even when the lighting surge or the like creeps, and the insulation degradation of the electric rotating machine can be monitored with a small measurement error.