云广±800kV直流输电投运后南方电网稳定特性研究

Study of Stability Characteristics of China Southern Power Grid with Yunnan-Guangdong ±800 kV DC System

从输电能力、直流运行特性、动态稳定方面研究云广±800kV直流投运后内南方电网安全稳定特性。研究表明:云广±800kV直流投运后南方电网西电东送输电能力显著提高,输电能力由动态稳定控制逐步转为热稳控制;云广±800kV直流联网运行时其双极闭锁故障是威胁南方电网安全稳定运行的最大风险,该直流系统孤岛运行是化解风险的有效措施;云广±800kV直流投运后南方电网主要区域振荡模态依然存在,但其阻尼因受新投产大水电机组电力系统稳定器(PSS)影响而显著增强。

Stability characteristics of China Southern Power Grid （CSG） with Yunnan-Guangdong ±800 kV DC system are investigated from aspects of West-to-East Power Transfer limit,DC operation characteristics and dynamic stability.The results show that as the ±800 kV DC system coming into commission,West-to-East Power Transfer limit of CSG increases remarkably,and will be restricted mostly by thermal limit instead of dynamic stability.With its sending converter connecting to the big AC system of CSG,the bipolar block of the ±800 kV DC system is the most dangerous factor for CSG＇s security and stability,but this risk can be defused by putting the ±800 DC system into isolating operation.The main regional oscillation modes of CSG still remain even the ±800 kV DC system comes into commission,but the damping of the modes will be enhanced by the hydro-power generation units with PSS being in operation.