适用于直流电网的多端口限流式直流故障保护方案

Multi-port Current-limiting HVDC Fault Protection Scheme for DC grid

直流电网保护中利用限流器(fault current limiter,FCL)和断路器(DC circuit breaker,DCCB)协调配合控制具有重要意义。文中提出一种采用晶闸管作为主要控制单元的多端口限流式(multi-portcurrent-limiting,MPCL)直流故障保护方案,具备保护多条线路、抑制故障电流等功能。限流电感储能增加了断路器的耗能容量需求,设计能够快速旁路限流电感的能量转移支路。分阶段对新拓扑的预充电、限流、断路及耗能过程进行理论解析,分析电压电流应力、避雷器耗能与MPCL保护方案关键参数的关系,给出IGBT及能量转移支路参数的设计。在PSCAD/EMTDC中对所提MPCL保护方案的限流、断路和重合闸能力进行仿真验证,证明MPCL保护方案可保护多条直流线路,并抑制故障电流发展,提升分断电流速度,减少对避雷器的耗能要求。

Coordinated control of the fault current limiter(FCL)and DC circuit breaker(DCCB)is of great significance in the DC grid.A multi-port current-limiting(MPCL)DC fault protection scheme using thyristor as the main control unit,which has the capacity of protecting multiple lines and suppressing fault current was proposed.The current limiting inductor energy storage increased the energy consumption capacity requirement of the circuit breaker,and an energy transfer path capable of quickly bypassing the current limiting inductor was designed.The theoretical analysis of the pre-charging,current-limiting,breaking and energy consuming processes of the new topology was carried out in stages.The relationship between voltage and current stress,the energy consumption of the arrester and the key parameters of the MPCL protection scheme was analyzed.The parameters of the IGBT and the energy transfer branch were given.The current limit,open circuit and reclosing capability of the proposed MPCL protection scheme were verified by simulation.It is proved that the MPCL protection scheme can protect multiple DC lines and suppress the fault current,improve the current interruption speed and reduce the energy consumption of the arrester.