Research on dynamic characteristics of permanent magnet brushless DC Motor operating mechanism in 126kV vacuum circuit breaker

According to an independent-developed motor operating mechanism of 126kV circuit breaker, the dynamic behavior was studied by simulation and experiment methods simultaneously. In this research, mathematical model of the actuator was established and dynamic load characteristics including equivalent moment of inertia and dynamic counter-force were analyzed in detail. Meanwhile, relationship between stroke of moving contact and rotating angle of driving motor was derived strictly. Based on the analyses above, transient magnetic field and dynamic parameters of driving motor were simulated by employing coupled field-circuit method which took the end winding leakage inductance into consideration. Opening and closing operation experiments were carried out by using the established test platform which combined motor operating mechanism with vacuum circuit breaker. The test results indicated that motor operating mechanism could be able to achieve opening and closing operation of 126kV vacuum circuit breaker reliably. The average closing velocity and opening velocity could reach 2.37m/s and 3.31m/s respectively, which totally met the requirement of vacuum circuit breaker. Simulation analyses of dynamic characteristics were in agreement with test results well. That verified the validity of the simulation analyses.