In our earlier paper, we proposed a new "Intelligent Operation" concept for high voltage SF6 gas circuit breakers, in which the moving contacts are self-adaptively controlled according to the system condition to optimize the breaking performance. To analyze and design the operation, a new model of high voltage SF6 gas circuit breaker is developed, and the moving characteristics of the new smart breaker are computed based on the new model. In this paper, we present details on how synchronous phase control technique is used to enable synchronization of the switching moment so that switching always takes place in a phase position that makes the arcing time optimal for breaking the fault current. A case study about electrical wear is quantitatively analyzed, according to the breaker's moving characteristics. Finally, we demonstrate the reliability improvement of the new type of high voltage SF6 gas circuit breaker.