621 / 2019-03-28 10:00:56

An Diode Clamped Multi-port DC Circuit Breaker for DC Grids

Hybrid HVDC circuit breaker,HVDC transmission

In order to effectively improve the operation reliability of the current-transferring type dc circuit breaker (CT-DCB), reduce the complexity of the structure, an improved CT-DCB, named the diode clamped multi-port DCB (DM-DCB) is proposed. The improved topology changes half of conducting branches of the original breaker to diode branches and adds the bypass switch in parallel with the load commutation switch to improve the protection of the DCB under the failure of the ultra-fast disconnector. On the premise of ensuring the same dc fault handling capacity, the investment cost is comparable to the CT-DCB, and less investment cost increment is introduced. A model of three-terminal dc grid is developed in PSCAD/EMTDC to verify the validity of the proposed breaker. Simulation result proves validity and feasibility of the proposed solution.