Fault Diagnosis Method of Inter-turn Insulation Failure for Circuit Breaker Control Coil

Abstract

The failure of insulation between control coils is an important cause of circuit breaker failure, from the perspective of engineering application, it is expected to accurately screen out this kind of indiscernible inter-turn fault, an effective diagnostic method must be explored. First, apply high-voltage dc (HVDC) pulse excitation to the control coil of the high-voltage circuit breaker, and the response voltage signal is denoised by continuous wavelet transform (CWT) to obtain the main frequency signal which can reflect the essential characteristics of the response; the V/t characteristic curves of the electromagnet coils are then compared with those of standard electromagnet coils at the same frequency and at the same voltage; finally, the variation rules of the integral flux and reluctance of the electromagnet coil under test are judged, so as to judge the inter-turn insulation fault.