A novel hybrid DC circuit breaker based on double mechanical switch

Abstract

The Hybrid DC circuit breaker is the key equipment for fault isolation in DC system. However, the existing forced converter hybrid DC circuit breaker still has the problems of high loss of auxiliary converter devices in main branch and high pre-charge voltage level. A novel hybrid DC circuit breaker based on double mechanical switch is proposed in this paper, under the premise of ensuring the two-way interruption of fault current, the main branch only adopts fast mechanical switch, and the low conduction loss of the main branch is realized by resistance zero-crossing circuit breaker. At the same time, the voltage level of pre-charging system is reduced by using controllable active oscillation circuit. Firstly, this paper introduces the proposed DC circuit breaker topology; Secondly, the working principle of fault current breaking is analyzed in detail; Finally, the performance of the proposed novel hybrid DC circuit breaker based on double mechanical switch is verified in PSCAD/EMTDC, which shows that the proposed DC circuit breaker has significant effectiveness.