Abstract:
DC circuit breaker (DCCB) is the key equipment for DC power system. Due to the diverse topologies and different operating characteristics, multi-type DCCBs might be configured at the same project. In this case, detailed modeling and reclosing of multi-type DCCBs are involved to study the fault isolation and recovery in system level, resulting in the increase of research difficulty. The working principles of typical hybrid/mechanical DCCB were presented, and with the equivalence of external characteristic (Volt-Ampere curve), universal model that can be used to simulate multi-type DCCB was established in PSCAD. Then, the natural residual voltage distribution pattern of the fault line after DCCB interruption was revealed and its mechanism was analyzed theoretically. The research shows that only using the natural residual voltage cannot distinguish permanent faults and transient faults. Therefore, to distinguish the fault type, a method based on unloading resistance was proposed for adaptive reclosing of the multi-type DCCB. In the end, study cases were conducted in PSCAD, verifying the universal model and the adaptive reclosing method for the multi-type DCCB.