Improved Integrated Hybrid DC Circuit Breaker for MTDC Grid Protection

Abstract

The current-limiting inductors are usually installed in the multi-terminal dc grid to limit the fault current rising speed. However, they will increase the energy dissipation pressure and fault isolation time of the dc circuit breaker, which puts forward higher requirements on the capacity of arresters in hybrid dc circuit breaker and the heat dissipation of grid equipment. Therefore, an improved integrated hybrid dc circuit breaker is proposed in this brief for applications in the multi-terminal dc grid. Compared with the fault isolation solution based on existing integrated hybrid dc circuit breakers, the proposed breaker has slightly higher cost of semiconductor switches but significantly reduced arrester capacity requirement and faster fault isolation speed by bypassing the inductance components. Extensive electromagnetic simulations and physical experiments verify the effectiveness of the proposed device.