Hybrid DC circuit breaker with current-limiting capability

Nowadays, traditional DC circuit breakers (DCCBs) are always expensive and lack current-limiting capabilities. Hence, this paper proposes a current limiting and low-cost hybrid DC circuit breaker (HCB). When a fault occurs, the paralleled inductors in the proposed HCB are converted to a series connection due to the cutoff of the converter module, effectively limiting the increase of fault current. Then the cascaded IGBTs undertake the transient interruption voltage. Energy dissipation circuits (EDCs) reduce the fault isolation time (FIT) by bypassing the current-limiting inductor during energy dissipation based on the metal oxide varistors (MOVs). Therefore, the proposed HCB can limit the rate of the fault current increase, reducing the FIT and cost. Finally, the feasibility of the proposed HCB is verified by a single-ended equivalent system and DC grid test systems built in PSCAD/EMTDC. In addition, the proposed HCB FIT is 33.7% quicker, its energy consumption is 87%, and its cost is lower than that of the traditional ABB HCB.