在多端柔性直流输电(VSC-MTDC)系统中,交流系统发生不平衡故障的情况下,对常规控制器与双序控制器的性能进行了分析.基于仿真软件PSCAD/EMTDC建立了三端柔性直流输电模型.在有功功率控制端交流系统侧出现不平衡故障的情况下,分别采用两种控制器进行仿真.仿真结果表明,当双序电流控制器应用于VSC-MTDC时,采用抑制直流电压脉动控制策略时可以减小故障期间直流电压的二倍频振荡;采用抑制交流侧负序电流控制策略时可以抑制故障端交流系统的负序电流.%This paper analyzed the performance of two different controllers when unbalanced fault occurs in AC system and established a VSC-MTDC system with three terminals by using PSCAD/EMTDC.Vector current controller and dual vector current controller were applied separately under AC system unbalanced fault of active power control side.The simulation results show that dual vector current controller can improve the performance of VSC-MTDC under AC system unbalanced fault of active power control side.When the control strategy of eliminating the DC voltage oscillation is applied,the oscillation of DC voltage is effectively suppressed;and when the control strategy of eliminating the negative-sequence currents is applied,the negative-sequence of AC system is effectively suppressed.
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