关键词: 特高压直流, 电网, 直流闭锁, 输电能力

Abstract: The Hami-Zhengzhou ±800 kV UHV DC project is the first DC project under construction in Xinjiang autonomous region and is planned to be put into operation in 2013. The influence of the project on the power grid stability in its commencement period is discussed and the impact of the project′s possible fault on the 750 kV AC connection project between Xinjiang and Northwestern power grid is checked. Based on the maximum power load of the Xinjiang power grid in the Winter period, a power flow and transient stability simulation analysis is conducted on the stability features of the power grid under the condition of monopole or bipolar lockout of the DC transmission lines and at the fault of the 750 kV AC transmission lines, and on the power grid stability variation with switch off measures of generators. Through simulation, the maximum transmission power of the AC section is determined under the condition of monopole lockout of DC system with different switch off measures of generators, and the effectiveness of generator switch off measures to increase the transmission capacity of AC power system is also verified. The conclusions obtained from this paper may provide a reference to the construction and security control strategy formulation of the Hami-Zhengzhou DC project.

Key words: ultra-high voltage DC, power grid, DC system lockout, maximum transmission capacity