A Novel Non-Invasive Method for Condition Monitoring of Circuit Breakers Based on Input Impedance Frequency Analysis

Abstract

Circuit breakers are indispensable components in modern power systems, and their reliable operation is essential for maintaining network stability, protection, and safety. Accurate monitoring of the interruption chamber of Circuit breakers is crucial for detecting incipient faults and enabling timely maintenance. This paper presents a novel condition monitoring approach based on frequency-domain analysis of the input impedance. An equivalent circuit model of the interruption chamber is developed using finite element simulations that incorporate the internal geometry and material properties of the CB. Simulation results demonstrate that the resonant frequency of the input impedance varies with changes in the condition of internal components. These resonance characteristics exhibit high sensitivity to internal defects, resulting in observable shifts in both the resonant frequency and the impedance magnitude. By comparing the input impedance spectra of healthy and faulty CBs, the proposed method enables accurate, non-invasive fault detection. It provides a promising tool for predictive maintenance of SF6 circuit breakers.