HIGH VOLTAGE INSULATION MONITORING APPARATUS AND HIGH PRESSURE INSULATION MONITORING METHOD

摘要

To provide a high voltage insulation monitoring apparatus and a high voltage insulation monitoring method capable of obtaining characteristics of a zero phase current transformer without causing a power outage even with an existing switch and capable of performing highly accurate insulation drop detection.SOLUTION: A high voltage insulation monitoring apparatus 10 includes a correction unit 36 that corrects a zero-phase current using a load current of each phase and characteristics of a zero-phase current transformer 24 and an insulation deterioration detecting unit 38 that detects a high resistance insulation drop. The correction unit measures the load current and the zero-phase current of each phase at least four times while the load current is flowing through a switch 20 and multiplies the load current of each phase by a correction coefficient, calculate the correction coefficient which is an unknown value of an equation that defines an error of the zero-phase current, and obtains an error by applying the correction coefficient to the equation by setting one of four measurement values as a reference value, using a difference between the load current and the zero-phase current of each of remaining three phases and the reference value.SELECTED DRAWING: Figure 1