一种基于最大短路电流限制的高压直流输电连续换相失败抑制方法

A Suppressing Method to Mitigate the Continuous Commutation Failure of HVDC Power Transmission Based on Limit of Maximum Short Circuit Current

为降低高压直流输电系统发生连续换相失败的概率,理论分析了连续换相失败发生机理及其影响因素,提出了一种基于最大短路电流限制的连续换相失败抑制方法,并以首次换相失败发生为触发信号,配合系统低压限流环节,对故障期间直流电流整定值进行修正,抑制连续换相失败的发生。基于CIGRE HVDC标准测试模型,在PSCAD/EMTDC中实现了所提出的控制方法。仿真结果表明,在不对称故障和三相故障下所提的优化控制策略均能有效抑制连续换相失败的发生,实现系统各项电气参数的平滑恢复,有效改善系统的故障恢复特性。

To reduce the probability of continuous commutation failure in HVDC power transmission system,the occurrence mechanism and influencing factors of continuous commutation failure are analyzed theoretically. A suppressing method of continuous commutation failure based on the limit of maximum short circuit current is proposed,which can be triggered by the signal of first commutation failure,together with voltage dependent current order limiter（ VDCOL）,and revises the DC current setting value during the faults,so as to mitigate continuous commutation failure. Based on the CIGRE benchmark test model of HVDC,the proposed control method is fulfilled in PSCAD/EM TDC. Simulation results showthat the proposed optimal control strategy can mitigate the continuous commutation failure under single-phase grounding and three-phase grounding fault conditions effectively,and realize the smooth recovery of the electrical parameters of the system,and improve the fault recovery performances of system effectively.