Multiport Hybrid DC Circuit Breaker With Reduced Fault Isolation Time and Soft Reclosing Capability

The hybrid dc circuit breaker is one of the most promising dc circuit breakers (DCCBs). However, its cost is relatively high, and the completion of its fault isolation is significantly delayed because of the large current limiting inductors configured in the multiterminal dc grid. Besides, due to the utilization of overhead lines, the probability of temporary faults is much increased, which means there is a great possibility that the power supply can be rapidly restored by reclosing DCCBs. However, the temporary faults must be distinguished from the permanent faults before the reclosing operation to avoid damaging the fragile power electronic equipment. Therefore, considering the above issues, a novel multiport hybrid dc circuit breaker (MHCB) is proposed in this article. The MHCB mainly has three advantages: the reduced implementation cost by sharing the expensive main breaker among multiple lines, the reduced fault isolation time by bypassing the current limiting inductor during energy dissipation, and the ability to reclose softly. Extensive simulations and experiments verify the effectiveness of the device. In addition, the comparison of the new device and existed solutions is presented.