Topology optimization and evaluation of multiport hybrid DC circuit breaker based on graph theory

The multiport hybrid dc circuit breaker (M-HCB) is a cost-effective choice for fault blocking in meshed HVDC system. Various M-HCB topologies have been proposed in recent years. However, the topology derivation has randomness and uncertainty. Whether the topology can be improved and how to derive new topology from existing topology has less discussion. In this paper, a topology optimization and evaluation method based on graph theory is proposed to deduce more M-HCB topologies from existing topologies. A series of new topologies is quickly derived from the proposed method, and the performance can be evaluated based on the feasible path calculation. Compared with the existing topology, the derived topologies have the advantages of cost and loss in specific application scenarios. Simulation and experiment results are given to verify the topologies. The comparison between the existing topologies proves the superiority of the deduced topologies and the feasibility of the proposed method.