一种新型HVDC直流限流器拓扑设计与分析

Analysis and Design of Topological Structure for A New HVDC Current Limiter

针对直流电流增加导致的换相失败问题,设计了一种电感式限流器,分析了其工作原理并建立了数学模型,该限流器基于电感通低频阻高频的特性,利用快速可控的电力电子器件实现直流电流向交流电流的转变,可安装于高压直流输电系统逆变站直流出口处。应用PSCAD/EMTDC软件对该拓扑结构的可行性进行验证,结果表明:在交流系统单相故障和三相故障下,该限流器均能限制直流电流幅值,在一定程度上降低传统高压直流输电换相失败的概率。仿真结果证明了理论推导的正确性和该限流器拓扑结构的可行性。

To study the commutation failure in HVDC caused by the increase of DC current, a inductive current limiter has been designed, whose working principle was analyzed and mathematic model was built up. For the characteristic of inductance, through which low frequency current can flow easier than high frequency current, and takes electric electronic component IGBT as key part of using its open and close to make DC current into AC current, a new DC current limiter of inductance is proposed. Its topology is given, and both operating principle and mathematical model are analyzed. Finally, a LCC-HVDC system whose DC line at inverter station side has a DC current limiter is modeled and investigated in PSCAD/EMTDC. The simulation results show that the new current limiter can limit the magnitude of current under different faults, which can improved the commutation failure immunity for HVDC system. The results show the reliability of the novel theory and feasibility of proposed topology.