具备直流故障隔离能力的新型MMC拓扑研究

Reaseach on the Topology of MMC with DC Fault Isolating Capability

对柔性直流输电的直流侧短路故障问题,提出了一种新型的能够自我阻断直流故障的子模块拓扑,该拓扑可以通过自身结构特性来阻断故障电流;在此基础上,为了抑制故障时子模块电容电压升高带来的不利影响,提出了具有阻尼电阻的子模块拓扑,该拓扑在阻断故障电流的同时还具有抑制子模块电容电压的作用.在PSCAD/EMTDC平台下搭建了9电平MMC-HVDC仿真模型,并验证了所提出新型拓扑的正确性.

To solve the MMC-HVDC dc-fault, a new sub-module topology with DC faults blocking capability was proposed,which could be used to block the fault current by its structure characteristic.On this basis,in order to restrain the adverse effects of sub-module capacitor voltage rising during the fault time, a new sub-module topology with a damping resistor was proposed.The topology not only could block fault current,but al-so had sub-module capacitor voltage suppression effect.An 9 level SBMMC-HVDC simulation model was built in PSCAD/EMTDC platform,and the simulation proved the proposed new topology was correct.