A Multi-Functional Multi-Port Hybrid DC Circuit Breaker for Flexible DC Distribution Networks

To quickly clear short-circuit faults and avoid the threat to power electronic devices, a multi-functional multi-port DC circuit breaker (MP-DCCB) is proposed. The fault current is limited by line inductors and the fault current limiter (FCL). The fault zone is selectively isolated through the coordination of current-flow branches (CFBs), selector switches (SSs) and the main breaker branch (MBB). Fault property identification and soft reclosing are achieved based on a multi-submodule collaboration strategy. By building equivalent models, the working principle is analyzed. The proposed MP-DCCB mainly has three advantages: the reduced cost by sharing the expensive MBB among multiple lines, the diminished transient current stress by the economic thyristor-based FCL, and the capability of fault-property identification and soft reclosing. The MP-DCCB is compared with typical DCCBs in terms of economic and technical performance. The results show that the proposed scheme is more suitable for flexible DC distribution networks.