Currently USES CKG4-10 fc as the main switch of the prepaid metering box, the role of the vacuum switch is open and close the load current, according to the demand of the market, we developed an intelligent switch controller, this controller and CKG4-10 fc vacuum switch to cooperate to use on the prepaid metering box, within 10 kv line bus short-circuit capacity of 300 mva, in the case of under 2500 kva transformer capacity, alternative circuit breaker function). 　　This switch type I has definite time overcurrent protection function, the instantaneous speed of circuit protection function, flow switch locking function and the short circuit latch function. This switch type II has definite time overcurrent protection function, the instantaneous speed of circuit protection function, flow switch locking function, short circuit atresia, zero sequence protection and fault record query function.