A Novel DC Circuit Breaker With Counter-Current Injection and IGCT Combined

The fast fault clearance in medium-voltage direct current (MVdc) grids requires the dc circuit breakers (DCCBs) with high breaking capability and low cost. The traditional hybrid DCCB realizes large current interruption relying on several insulated gate bipolar transistors in parallel, which results in difficulty of cost reduction. In this article, a novel DCCB with counter-current injection and integrated gate-commutated thyristor (IGCT) combined is proposed and analyzed. By combining forced commutation and IGCT, the large current breaking capability can be realized and the low cost is guaranteed. The simulation of the proposed DCCB is performed to evaluate the fault current breaking capability and influence of circuit parameters consisting of stray parameters and precharged capacitors on current commutation processes. Furthermore, a prototype of the 10-kV MVdc circuit breaker with 20-kA breaking capability is developed, and then the fault current breaking test is carried out to verify the validity of the proposed topology which can cut off current within 2.5 ms.