Development of four-terminals DC circuit breaker based on commutating path multiplexing

Multi-terminal flexible DC power grid plays an important role in large-scale new energy integration, which usually requires the installation of multi-terminal DC circuit breaker(MTCB) at the intersection of multiple DC lines. At present, the research on multi-terminal DC circuit breaker is mostly limited to theoretical simulation calculation, and there are few experimental studies and engineering applications. In this paper, a four-terminals DC circuit breaker based on commutating path multiplexing is proposed, which combines with the compact natural commutation scheme of hybrid gap, greatly reducing the cost and volume of the circuit breaker. The commutation characteristics of four-terminals hybrid DC circuit breaker equivalent prototype at 10kV voltage level were tested. On this basis, the equivalent prototype of the circuit breaker test results show that under 10kV voltage level, the four-terminals circuit breaker topology can achieve breaking of 11kA in 2.8ms by natural commutation method.