Dynamic fault analysis model development for vacuum circuit breaker action

Abnormal breaking, rejection, or misoperation in vacuum circuit breakers primarily occurs due to failures of the breaking solenoid mechanism. Therefore, a comprehensive analysis model for the operating state of breaking solenoids is of great significance in terms of power system stability. For this reason, a dynamic simulation model of this issue is proposed in this study. First, the operating principle of a breaking solenoid is deduced to establish the analysis model. Thus, the operation state of the moving iron core under normal conditions is analyzed. Second, the analog current waveform characteristics under fault situations are compared with those under normal situations. Then the effects of fault circuit breaker breaking are systematically analyzed. Finally, an analog shunt experiment is conducted on circuit breaker shunt solenoid faults, including poor contact, core jamming, and inter-turn short circuit faults. The experimental shunt coil current under faults is collected and compared with simulation results. The model performance is verified through the circuit breaker breaking fault experiments. Accordingly, it can provide a crucial solution for circuit breaker solenoid mechanisms in fault analysis, monitoring, and evaluation.