A Comprehensive Review of Multiport DC Circuit Breakers for MTdc Grid Protection

Voltage source converter–based multiterminal dc (MTdc) grids, including high- and medium-voltage levels, have attracted attention in recent years and developed fast. To protect the MTdc grids selectively, the dc circuit breaker (DCCB) is identified as the best choice. However, due to the high unit price and the required large number of DCCBs in the future large-scale MTdc grids, the total investment cost is unacceptable. Besides, the large volume and weight also limit their applications. To solve these problems, a variety of multiport dc circuit breakers (MPCBs) are proposed, which achieve significantly reduced costs and footprints by component sharing and device integration. This article first introduces the classifications and the basic principles of the existing MPCBs, and furthermore summarizes their technical requirements. Then, the economic and functional analysis of each MPCB is presented, and the performance comparisons among different topologies are elaborated. Finally, the challenges and future trends of the MPCBs are discussed and the findings are concluded.