大规模特高压交直流混联电网特性分析与运行控制

Characteristic Analysis and Operational Control of Large-Scale Hybrid UHV AC/DC Power Grids

我国正处在特高压电网的高速发展期,电网特性持续发生重要变化,对电网运行提出了新的要求。为此,文章分析了电网运行面临的形势和存在的问题,在深入研究特高压大电网特性的基础上,阐明了当前电网正处于"强直弱交"过渡期这一基本属性,概括了当前电网主要运行特点,主要包括:交直流、送受端耦合日趋紧密,故障对电网运行的影响由局部转为全局;新能源、直流输电大规模投产使电网频率和电压稳定问题日益突出;电网稳定范畴进一步拓展,电力电子化特征凸显。探讨了加强主网架结构、提升交直流仿真技术、修订稳定计算标准、完善控制策略、强化频率和电压控制受端、提升新能源涉网性能等应对措施的效果及初步方案,旨在有效保障大电网安全运行。

Power grids in China are at high-speed development period of Ultra High Voltage（UHV）. Characteristics of power grids keep changing, and new requirements are put forward on power grid operation. Based on in-depth analysis of operation characteristics of UHV power grids, basic characteristics of power grids are concluded as ＂strong DC and weak AC＂. Main features of power grid operation performance are summarized as follows： coupling between AC and DC, sending and receiving ends becomes more and more closer; influence of faults on power grids extends from local to global; grid frequency and voltage stability problems become increasingly prominent for mass generation of renewable power and DC transmission; power grid stable category has been expanded; power electronic characteristics is prominent. Strategies in response to above questions are further discussed, including strengthening backbone structures, enhancing simulation technology, amending stability computing standards, improving operation control strategy and frequency and voltage control ability, and promoting protection measures of clean energy related to grids, etc. It is valuable for guaranteeing security and stability of the power system.