Arc Characteristics in Multiple Pole DC Circuit Breakers

Due to the absence of zero crossings in a DC current compared to an AC current, DC arc extinguishing is difficult in DC circuit breakers (DCCB). To overcome this difficulty of arc extinguishing, DC circuit breakers are frequently designed and built by series connecting multiple poles of a 3 phase AC circuit breaker. During the mechanical contact opening, the fault current of the DC circuit gradually reduces as the arc path resistance increases with time. The arc can be extinguished quickly if the arc path resistance can be increased quickly. By increasing the series connected switches, the arc path resistance can be increased. This paper presents the arc characteristics of a multiple pole DC circuit breaker based on analytical and experimental approaches.