A novel hybrid DC circuit breaker for nodes in multi-terminal DC system

Abstract

DC fault protection is one of the biggest challenge to multi-terminal direct current (MTDC) systems, because DC current has no natural zero crossing point. To overcome this problem, hybrid DC circuit breaker (DCCB), which serves as a promising solution to the isolation of DC faults, has been developed. However, hybrid DCCB contains a huge number of power semiconductors, which is costly and inefficient especially in MTDC. This paper proposed a novel hybrid DCCB for nodes in MTDC system. By optimizing the topology and corresponding control strategy of traditional hybrid DCCB, the requirement of power semiconductors is reduced without degrading the performance. The novel hybrid DCCB is verified by simulations of a four-terminal radial DC grid with MATLAB/Simulink.