Optimisation of operating mechanism and drive system for medium voltage circuit breakers

This paper identifies several directions to improve the performances of the operating mechanism for medium voltage circuit breakers in order to get variable moving characteristics of the moving contact adjusted to the value of the switching current. Different drive solutions currently used in the operation of vacuum circuit breakers and SF6 were analyzed comparatively, as well as the performances they have to meet depending on the application. The solution proposes the use of a system with a microprocessor able to independently control the operation of moving contacts by stepper motors and the acquisition of the circuit breaker functional parameters.