特高压规划电网安全稳定性研究

为了对 2018水平年国家特高压规划电网的输电网络结构进行检查和考核，该文应用数模混合式电力系统实时仿真装置，进行多项N-1故障和N-2故障的实时仿真试验，对±800 kV直流系统与送受端交流系统的相互影响进行深入研究。研究结果表明，从系统安全稳定角度出发，该网架结构可行；±800 kV直流发生双极闭锁故障时，特高压交流通道部分母线电压偏低，建议通过加强无功补偿装置等手段来改善故障后系统的电压水平。研究还发现，因向家坝-南汇、溪落渡左-株洲、溪落渡右-浙西这3回特高压直流送端换流站距离很近，任一直流发生双极闭锁时整流站换流母线的暂态过电压均会导致其它2回直流发生换相失败，建议设立专题对此进行深入研究。

Security and Stability Study on Planned Ultra High Voltage Power Grid

In 2018, according to the transmission planning scheme evaluated in 2005, a large amount of hydro power in southwest China is projected to transmit to east and central China through four ±800 kV ultra high voltage direct current (UHVDC) links and some parallel 1 000 kV ultra high voltage alternating current (UHVAC) transmission lines. In order to examine the technical feasibility of this scheme, a series of study were carried out using a hybrid real-time simulator. The network performance based on minor and severe emergencies was investigated. The interactions among ±800 kV DC links, connected AC system and the impact of multi-infeed DC power on east-China network were analyzed. The results show that the 2018 power grid scheme is feasible from the transmission system security and stability perspective. However, some areas of the transmission system reflected lower than anticipated voltage when ±800 kV UHVDC bipolar emergency outage occurs. It is recommended that reactive power compensation can be installed for voltage improvement. This feasibility study also revealed that when high enough over-voltage occurs at rectifier commutation bus, it may result in commutation failure at the inverters. Hence, for three of the UHVDC links mentioned in this paper (whose locations of rectifier stations are close in proximity), when bipolar emergency outage occurs at one of them, it could lead to commutation failure at other two inverters due to the over-voltage at commutation buses of the rectifiers.