Arc extinguishment for DC circuit breaker by PPTC device

摘要

An ideal circuit breaker should supply electric power to loads without losses in a conduction case and isolate completely the load from the power source by providing insulation strength in a break case. In AC circuit breaker, it is relatively easy to break the fault current because the AC current becomes zero at every half cycle. However, in DC circuit breaker, the fault current should be reduced by generating a high arc voltage at the breaker contact point. If the DC circuit breaker does not take sufficient arc voltage and allows the continuous flow of the arc fault current with high temperature, it may lead to a large fire. A semiconductor circuit breaker with a power electronic device has many advantages: the breaking time is quick, the arc is not generated, and the noise is small as compared with the mechanical circuit breaker. Yet, it has a problem that a large capacity cannot be applied by large conduction loss. In this paper, to take advantages of low conduction loss of mechanical circuit breaker and arc-less breaking characteristic of semiconductor device, an arc extinguishing technology of DC circuit breaker with Polymeric Positive Temperature Coefficient (PPTC) device is proposed and evaluated through experiments.