一种双电容换流型混合式直流断路器

A Double Capacitor Commutated Hybrid DC Circuit Breaker

混合式直流断路器可以快速、准确隔离线路故障,在直流电网故障清除难题中发挥重要作用。为解决直流断路器开断能力要求高、限流能力弱、制造成本大、故障隔离速度慢等问题,提出一种双电容换流型混合式直流断路器(Double capacitor commutated hybrid DC circuit breaker,D-C-DCCB)拓扑。构建断路器时,巧妙利用自充电通路实现电容预充电及反向充电后电容能量的耗散。通过电容反向充电与阻感限流支路降低故障电流上升速率及峰值,利用限流电阻与二极管组实现限流电感,完成限流工作后被短路及储存能量耗散,加快故障隔离速度的同时,有效减少了避雷器吸收能量。对所提断路器的拓扑结构及工作原理进行分析及推导,在PSCAD/EMTDC中对所提断路器拓扑进行了四端直流电网仿真验证,与现有的直流电网故障清除拓扑在性能及经济性方面进行了对比,证明了所提断路器具有性能好、经济性高的优点。

Hybrid DC circuit breakers can quickly and accurately isolate line faults,which plays an important role in DC grid fault clearance problems.In order to solve the problems of DC circuit breaker high breaking capacity,weak current limiting ability,large manufacturing cost and slow fault isolation speed,a double capacitor commutated hybrid DC circuit breaker(D-C-DCCB)topology is proposed.When the circuit breaker is built,the self-charging path is cleverly used to realize the dissipation of the capacitor energy after capacitor precharge and reverse charging.Through the capacitor reverse charging and resistive inductive current limiting branch,the fault current rise rate and peak are reduced,the current limiting resistor and diode bank are used to realize that the current limiting inductor is short-circuited and the stored energy is dissipated after completing the current limiting work,which accelerates the fault isolation speed and effectively reduces the energy absorbed by the arrester.The topology and working principle of the proposed circuit breaker are analyzed and derived,and the four-terminal DC power grid simulation verification is carried out in PSCAD/EMTDC,and the performance and economy are compared with the existing DC grid fault removal topology,which proves that the proposed circuit breaker has the advantages of good performance and high economy.