调相机在电力系统中的发展应用与动态特性

Development Application and Dynamic Characteristics of Synchronous Condenser in Electric Power System

[目的]伴随以新能源为主体的能源互联网架构的构建,特高压直流输电工程成为电力输送的重要方式,电网呈现出“强直弱交”新特性。同步调相机凭借其无功响应速度快、电压支撑能力强等良好的动态特性,在应对电网“强直弱交”特性中具有独特优势。[方法]为研究调相机在特高压直流工程中的应用,总结了调相机的发展历史,介绍了火电机组改造调相机、新一代大容量调相机、分布式调相机等国内几种主要类型的调相机的发展现状,分析了调相机的工作原理和动态特性,梳理了调相机较SVC等无功补偿装置具备的优势、大容量调相机与分布式调相机各自的适用场景和现有配置策略。[结果]在PSCAD/EMTDC平台搭建含调相机的直流送出系统仿真模型,仿真验证了调相机对受端换相失败和换相失败引发的送端暂态过电压的抑制能力、调相机在滞相运行下的动态无功补偿能力。[结论]分析表明调相机可以对暂态过电压和换相失败产生良好抑制作用,滞相运行不会影响调相机的无功响应速度和动态无功支撑能力,具有参与换流站稳态补偿的工程应用前景。

[Introduction]With the establishment of the energy Internet architecture mainly relying on new energies,HVDC transmission has become an important way of power transmission,power grids present a new characteristic of"strong DC and weak AC".Synchronous condensers have unique advantages in dealing with the issue of"strong DC and weak AC"by virtue of their dynamic performance such as fast reactive power response and strong voltage support capability.[Method]To study the application of synchronous condensers in HVDC works,this paper summarized the development of synchronous condensers,introduced the current development status of several major types of synchronous condensers in China,such as synchronous condensers for transforming thermal power units,new-generation large-capacity synchronous condensers,distributed synchronous condensers,analyzed the working principle and dynamic characteristics of synchronous condensers.Then the paper summarized the virtues of synchronous condensers when compared with other reactive power compensation devices such as SVC,the application scenarios,existing configuration strategies of large-capacity synchronous condensers and distributed synchronous condensers.[Result]Finally,a simulation model of DC transmission system with synchronous condensers is built on the PSCAD/EMTDC platform.The simulation verify the suppression capability of failure,as well as the dynamic reactive power compensation capability under lagging phase operation.[Conclusion]The analysis shows that synchronous condensers have adequate suppression of transient overvoltage and commutation failure and their reactive power response speed and dynamic reactive power support capability will not be affected by lagging phase operation,which contributes to their prospect of engineering application for steady-state compensation in converter stations.