大型互联区域电网解列后送端电网频率特性及高频切机方案

Frequency Characteristics of Power Grid at Sending End of Split Large-Scale Interconnected Regional Power Grid and Corresponding Over-Frequency Generator-Tripping Scheme

目前,我国已经形成华北—华中特高压交流联网格局,联网初期有必要研究特高压联络线解列后,2个区域电网的频率稳定性。以华中(含川渝)电网调度数据为基础,通过推导大型互联区域电网频率偏差的解析式,把握了频率变化过程中最高频率和稳态频率特性;在以上工作基础上,再通过构建华中电网的等值单机带负荷模型,研究华中电网高频切机的最佳频段、最少切机量和切机各轮次的较优比例。最终,提出了适合于华中电网的高频切机方案,并验证了其适应性。

At present an ultra high voltage （UHV） AC interconnected structure composed of North China power grid with Central China power grid has been formed, and at the beginning stage of the interconnection it is necessary to research the frequency stabilities of North China power grid and Central China power grid after the splitting of the interconnected power grid via the UHV tie line. Based on the dispatching data of Central China power grid, which includes the dispatching data of Sichuan power grid and Chongqing power grid, the analytic expressions of the frequency deviation of large-scale interconnected regional power grid are derived to grasp the highest frequency and the steady state frequency characteristics during the frequency variation; on this basis, by means of constructing equivalent loaded single machine model of Central China power grid the optimal frequency band, the least capacity of the tripped generators and the more appropriate proportions for different tripping rounds during the over-frequency generator tripping in Central China power grid are researched. Finally, an over-frequency generator-tripping scheme suitable for Central China power grid is proposed, and its adaptability is validated by simulation results.