一种带缓冲支路的双向限流混合型直流断路器拓扑

直流线路发生短路故障时,故障电流上升速率极快且对断路器耗能支路冲击较大,对此在混合型直流断路器中引入一种缓冲支路和双向限流回路,形成一种带缓冲支路的双向限流混合型断路器,在电流正向或反向流通时均能快速清除直流线路故障,并有效抑制故障电流上升和减小故障电流对耗能支路的冲击。对断路器动作各阶段的电路进行理论分析,并在PSCAD平台搭建两端VSC-HVDC模型进行仿真验证,仿真结果表明提出的断路器能在快速清除故障的同时减小故障电流对耗能支路的冲击,有效限制故障电流的上升速率。

A Topology of Bidirectional Current Limiting Hybrid DC Circuit Breaker with Buffer Branch

When a short-circuit fault occurs in the DC line,the fault current rises very quickly and has a large impact on the energy-consuming branch of the circuit breaker.For this reason,a buffer branch and a two-way current limiting circuit are introduced into the hybrid DC circuit breaker to form a two-way current-limiting hybrid circuit breaker with buffer branch,which can quickly clear the DC line fault when the current flows in the forward or reverse direction,and effectively suppress the rise of the fault current and reduce the impact of the fault current on the energy-consuming branch.The circuit at each stage of the circuit breaker operation is analyzed theoretically,and the VSC-HVDC model with twoends is established on the PSCAD platform for simulation verification.The simulation results show that the proposed circuit breaker can quickly clear the fault while reducing the impact of the fault current on the energy-consuming branch,and can effectively limit the rising rate of fault current.