一种新型电感激励换流式高压直流断路器及其仿真研究

高压直流断路器是多端柔性直流电网中直流故障快速切除的关键设备,是柔性直流电网安全可靠运行的重要保障。针对已有电感激励换流式直流断路器存在的问题,研究提出一种新型电感激励换流式高压直流断路器方案,在转移支路上集成换流驱动电路,避免脉冲变压器副边线圈长期通流;并通过判断线路电流方向,在激发电流正半波内完成正反向换流,缩短反向换流时间,避免电力电子器件关断前的大电流冲击。通过PSCAD/EMTDC仿真验证了新型直流断路器方案的可行性,正反向换流时间均小于50μs,短路电流开断时间小于3ms,具有通态损耗小、自然冷却、全电流开断和重合闸等特点。

Research on A Kind of High Voltage DC Circuit Breaker Based on Novel Inductance Drive Commutation and Its Simulation

High voltage DC circuit breaker is the key equipment for fast DC fault removal in multi-terminal flexible DC power grid, and it is the important guarantee for the safe and reliable operation of the flexible DC power grid. In view of the problems in the existing DC circuit breakers based on inductance drive commutation, a kind of high voltage DC circuit breaker scheme based on novel inductance drive commutation is proposed in this paper. The current commutation drive circuit is integrated in the transfer branch of DC circuit breaker, which can avoid long-term flow state of auxiliary side coil of pulse transformer. The positive and reverse current commutation is can be realized in positive half cycle of excitation current by judging direction of line current, which shorten reverse current commutation time, avoid the impact of large current on power electronic devices before turning off. The feasibility of the new DC circuit breaker scheme is verified by PSCAD/EMTDC simulation,which can realize positive and reverse current commutation in less than 50μs,achieve short circuit breaking in less than 3 ms,and has the characteristics of low flow state loss,natural cooling,full current breaking and reclosing.