INSULATION MONITORING DEVICE

摘要

An insulation monitoring device that carries out insulation monitoring of a power system or load apparatus using, for example, an Igr method includes a table in which a monitoring setting value Irref greater than a resistance component error current flowing in accordance with the sum of the electrical capacitance of a capacitor configuring a noise filter on the input side of the load apparatus and the ground insulation capacitance of the power system is set in advance in accordance with an operating schedule of the load apparatus, a monitoring setting value computing unit that outputs the monitoring setting value Irref read from the table in accordance with a current time according to a clock, and an insulation evaluation unit that detects an insulation failure caused by a decrease in ground insulation resistance when a resistance component current extracted by an Igr extraction unit exceeds the monitoring setting value Irref.

主权项

1. An insulation monitoring device that detects leakage current flowing back via a ground insulation resistor of a power system or load apparatus connected to the power system, calculates from the leakage current a resistance component current of a same phase as a reference voltage superimposed on the power system, and detects an insulation failure caused by a decrease in a ground insulation resistance when the resistance component current exceeds a monitoring setting value, the insulation monitoring device configured to monitor the power system to which a noise filter including a capacitor is connected when the load apparatus operates, the insulation monitoring device comprising:
a table in which the monitoring setting value greater than a resistance component error current flowing in accordance with a sum of an electrical capacitance of the capacitor and a ground insulation capacitance of the power system is set in advance in accordance with an operating schedule of the load apparatus; and a monitoring setting value computing unit that outputs the monitoring setting value read from the table in accordance with the operating schedule at the current time, wherein the insulation monitoring device is configured to use the monitoring setting value output from the monitoring setting value computing unit in a comparison with the resistance component current to detect insulation failure.