基于晶闸管的电压钳位型混合直流断路器

A Novel Voltage Clamp Type Hybrid Direct Current Circuit Breaker Based on Thyristors

直流断路器是保障直流电网安全稳定运行的关键设备,而当前的直流断路器方案普遍存在故障清除速度慢、限流效果差、重合闸时间长等问题。为解决上述问题,提出一种基于晶闸管的电压钳位型混合直流断路器。所提直流断路器通过可变钳位电压迫使故障电流下降过零,实现故障快速清除;故障清除期间不会加剧短路电流的上升,具备良好的限流能力;具备快速重合闸功能,适用于直流电网瞬时性故障场景。阐述所提断路器的拓扑结构与工作原理;对其开断过程展开理论推导;最后,分别在PSCAD/EMTDC两端直流系统、四端直流电网模型中验证其有效性与适用性。

Direct current(DC) circuit breaker is one of the most important devices to keep the continuous operation of the DC grid. However, nowadays the DC circuit breakers are still with the problems of long-time current interruption, insufficient current limiting effect and low-speed reclosing. A novel voltage clamp type hybrid DC circuit breaker based on thyristors was proposed in this paper. The proposed DC circuit breaker has the advantage of quick fault-isolation ability by employing the clamped voltage to decrease the fault current to zero. Moreover, it is with sufficient current limiting ability which may not accelerate the increasing of the fault current during its operation, and also with the high-speed reclosing ability that makes it more applicable in the DC grid. Finally, the effectiveness and applicability of the proposed breaker was validated in the point-to-point high voltage DC(HVDC) system and four-terminal DC grid respectively.