INSPECTION SYSTEM FOR DIGITAL TYPE PROTECTION RELAY

摘要

PROBLEM TO BE SOLVED: To provide an inspection system for digital type protection relay, capable of determining presence/absence of abnormality or failure with high detection precision, particularly in an analog circuit.SOLUTION: The inspection system for digital type protection relay includes: a superposed signal generator 20 for inputting an analog test signal formed by mixing a fundamental wave component with a harmonic component into an analog input circuit 12 of the digital type protection relay 10 at power failure; an A-D converter 13 that converts a signal after the test signal is output from the analog input circuit into a digital signal; and a one-chip microcomputer 14 that extracts the fundamental wave component and the harmonic component from a digital signal obtained by the conversion and determines whether or not these components are normal based on the magnitude of each signal of the obtained components.