A hybrid circuit breaker for DC-application

The development of large scale DC microgrid and high voltage direct current (HVDC) power grid requires a reliable, fast and low-loss circuit breaker. In spite of the advantages of DC gird such as low loss and no reactive power, DC grid has major disadvantages concerning control and switch actions. A new hybrid breaker with forced commutation is proposed in this paper, which is able to interrupt the fault current in several milliseconds. Furthermore, zero-current open of mechanical switch is achieved in this topology, and the breaker could be maintained in conducting state even if the gate driver of the semiconductor devices suddenly experiences blackout. The breaker can be applied in both VSC-HVDC system and DC micro grid. The design principles of the proposed hybrid breaker are presented and verified by simulation results.