Research on mechanical fault diagnoses methodology of a circuit breaker based on the voltage and current during its operation

The performance of a circuit breaker during its operation has great impact to the power system security and is of great concern to the operation and management department of power grid. This paper presents a new method to acquire the performance information of the circuit breaker during its connecting/disconnecting operation through the voltage and current waveforms.. Due to capacitance effects between dynamic and static contact, the voltage and current parameters in the process of connecting/disconnecting can be decomposed into two parts by orthogonal transformation method. The two parts are active and reactive power. The reactive component is generated by the capacitance effects. When the circuit breaker mechanical failure, particularly in velocity of contact anomalies, the capacitance effects will naturally be affected, that is, the reactive component will contain abnormal part inevitably. This method can effectively suppress interference, highlight the major characteristic quantities of the circuit breaker, and evaluate its mechanical performance.