柔性直流接入对弱受端电网恢复特性的影响及优化措施

随着柔性直流输电系统电压等级和输电容量不断提升,采用电压源型换流器的柔性直流输电技术在我国得到了大量应用,同时其对电网的影响也进一步增强。文中基于PSD-BPA机电暂态仿真软件中新开发的计及故障穿越策略的柔性直流控制系统,比较了不同直流接入方案下弱受端电网受扰恢复特性的差异。在此基础上,分析了柔性直流控制方式、直流传输功率大小以及故障穿越控制策略等因素对换流站动态有功和无功功率特性的影响。最后针对西藏弱受端电网电压稳定问题提出了优化方案,仿真结果表明优化柔性直流故障穿越控制关键参数可以改善弱受端电网故障后的恢复性能。

Influence of VSC-HVDC interconnection on recovery characteristics of weak receiving-end grid fault and optimization measure

With the continuous improvement of the voltage level and transmission capacity in VSC-HVDC, the VSC-HVDC transmission technology using voltage source converters has been widely used in China, and its impact on the power grid is further enhanced. Firstly, based on a newly developed VSC- HVDC control system which takes into account fault crossing strategy in the electromechanical transient simulation program PSD-BPA, the differences of disturbance recovery characteristics of weak receiving-end power grid under different HVDC interconnection schemes are compared. On this basis, the influence of VSC-HVDC control mode, transmission power and fault traversal control strategy on dynamic active and reactive power characteristics of converter station is studied. Finally, an optimization scheme is proposed to solve the voltage stability problem of Tibet weak receiving-end power grid. The simulation results show that optimizing the key parameters of VSC-HVDC fault traversal control can improve the recovery performance of weak receiving-end grid after fault.