Research on the action stability of vacuum circuit breakers with permanent magnet actuator

In order to improve the performance of vacuum circuit breakers with permanent magnet actuator (PMA), restrain the flow and overvoltage in the power system effectively. The current in coil is controlled during opening and closing of vacuum circuit breaker (VCB) and the characteristics of contact are controlled on the method of closed loop by using pulse width modulation (PWM), and the controlling model is established for dynamic analysis. 12kV VCB with PMA and a controller based on DSP are designed and tested, in order to meet the characteristics of opening and closing of VCB, their initial voltage is from 150V to 200V. The results show that the controller designed with the new method could effectively control the speed of the moving contact, ensure the stability of the action time, and then the time deviation of open or close VCB could be limit to ±0.3ms, lay the foundation for application of synchronous switching.