馈入直流对四川电网暂态电压稳定性的影响分析

Analysis on Influence of HVDC Feed-in on Transient Voltage Stability of Sichuan Power Grid

摘要:

四川电网暂态电压稳定问题,是在负荷中心从内部电源大功率受电同时从外部电网大功率受电的方式下严重故障产生的问题，直流馈入运行将进一步恶化四川电网的暂态电压稳定性。针对该问题，首先提出了一种计及惩罚函数、考虑全节点全故障的运行方式暂态电压稳定评估指标，可全面量化评估运行方式的影响因素，支持实现自动搜索及制定电网合理而偏恶劣的运行方式。进而，揭示了四川暂态电压稳定机理是在负荷中心从内部电源和外部电网同时大功率受电方式下枢纽站点交流故障产生的巨大阻塞功率远距离涌动传输导致的问题，并重点分析了德宝直流馈入运行导致负荷中心受电比例增大和动态电压支撑能力削弱是降低暂态电压稳定问题的两点根本原因。最后，提出了改善暂态电压稳定性的优化直流控制参数措施，为暂态功角与电压稳定交织的类似电网安全稳定分析提供了参考、借鉴作用。

Abstract:

Transient voltage stability of Sichuan power gird is a problem caused by a serious malfunction when load center is simultaneously received from internal high power supply and external gird. In addition, HVDC feedin will further deteriorate transient voltage stability of Sichuan power gird. Focus on this problem, an evaluation index of transient voltage stability is firstly proposed considering penalty function and operation mode of all nodes with all faults, which can automatically quantify the factors affecting the operation mode, and support the realization of automatic search and compilation reasonable bad operation mode. Secondly, the mechanism of transient voltage stability in Sichuan power gird is revealed, that is caused by large range surge of huge blocking power after AC failure occurred in the mode of power supply and load power consumption. The two root causes for decreasing transient voltage stability in Sichuan power gird are mainly analyzed, that is, the increasing of receiving ratio in load center caused by DeyangBaoji HVDC feedin operation and the weakening of dynamic voltage support capacity. Finally, the measures including optimizing HVDC control parameters are presented to improve the transient voltage stability of Sichuan power gird, which can provide a reference for the security and stability analysis of similar anglevoltage intertwined power grid.