适用于直流电网的预限流型直流断路器拓扑

为提高多端直流电网在直流故障下的运行可靠性,同时降低对直流断路器分断能力的要求,提出了一种适用于直流电网的预限流型直流断路器拓扑,当电网出现过电流时预先将限流回路投入,并根据故障检测结果决定切除故障线路或恢复正常运行。该拓扑使用辅助电容和半控型器件晶闸管实现了限流电感的快速投切与故障电流快速切除,能有效抑制故障电流,并具备一定的经济性。为验证所提拓扑在预限流和快速分断方面的可行性,在PSCAD/EMTDC中搭建了四端直流电网仿真模型,并通过仿真结果验证了所提拓扑在抑制故障电流、隔离故障线路方面的有效性。

Topology of DC Circuit Breaker with Pre-current-limiting Capability for DC Grid

To improve the operation reliability of multi-terminal DC grid with DC faults and reduce the interrupting capability requirements of DC circuit breakers, this paper proposes a topology of DC circuit breaker with pre-current-limiting capability for DC grid. In the proposed topology, the current-limiting circuit can be put into operation in advance when the overcurrent appears in the grid, and it can be decided to interrupt the fault current or recover to normal operation according to the fault detection results. This topology adopts auxiliary capacitor and half-controlling device thyristor to achieve the fast switching of current-limiting inductor and the fast interruption of fault current, which can effectively limit the fault current and has certain economy. To verify the feasibility of the proposed topology in terms of pre-current-limiting and fast interrupting, a simulation model of four-terminal DC grid is built in PSCAD/EMTDC. Simulation results verifies the effectiveness of the proposed topology in limiting fault current and isolating faulty lines.