Multiport Hybrid DC Circuit Breaker With Current Flow Control for MTDC Grids

The multiterminal dc (MTDC) grid plays an important role in large-scale power transmission and renewable energy integration owing to its excellent performance. However, there are still some problems existing in the MTDC grid, such as difficult fault current interruption and current flow control, which impedes its development. Currently, the mentioned two problems can be separately solved by hybrid dc circuit breaker (HCB) and current flow controller (CFC). However, when configured separately, they are expensive and have large footprints. Therefore, this article proposes a multiport hybrid dc circuit breaker (MHCB) with current flow control capability. The HCBs near the same dc bus are first integrated into a single MHCB and then novel CFCs are embedded into the MHCB to replace the load commutation switches. Compared with the existing MHCBs, the proposed topology shows advantages in the aspects of implementation cost, power loss, and operation speed. The operation principle is analyzed and the basis for parameter design is given in detail. The effectiveness of the proposed topology is verified by extensive simulations and experiments. Besides, the proposed MHCB is compared with the existing solutions.