特高压直流工程无功平衡和补偿策略

Study on Reactive Power Balance and Compensation Strategy for UHVDC Project

换流站无功补偿是特高压直流输电系统设计的重要组成部分,而特高压换流站和交流系统无功平衡与补偿策略对计算特高压换流站无功平衡和无功补偿总容量非常重要,因此根据特高压换流站无功消耗的特点,结合送端金沙江区域交流系统的不同运行方式,采用BPA3.0程序计算后得出送端金沙江区域交流系统无功提供总能力为2 400 MVA,无功吸收总能力为200 MVA;3个换流站无功补偿推荐采用独立平衡策略;无功大组容量限值为1 000 MVA。主要研究结论已用于特高压直流输电系统的成套设计工作。

The first stage Jinshajiang river project is located in the area of Sichuan province, including 3 hydro power stations in Jinshajiang river. Three ±800kV UHVDC bipole lines transmit power from south-west China to 4 eastern provinces of central China and East China power grid, namely Xiangjiaba-Shanghai, Xiluodu left-Zhuzhou and Xiluodu right-Zhexi, each has transmission capacity 6400MW. The study on reactive power compensation of converter station is an important component in the design of UHVDC project. The paper gives the independent balance principle for the reactive power compensation calculation of UHVDC converter stations. Considering the feature of UHVDC reactive power consumption and various AC system operating modes, the reactive power supply and absorption capacity of Jinshajiang AC system are 2400 MVA and 200 MVA respectively, which are verified by BPA simulation. The maximum dynamic change in the fundamental frequency components of both converter AC bus voltages shall not exceed 2%. No switching operation shall result in a change in steady state converter AC bus voltage greater than the lesser of 1% or a value equivalent to 75% of one step of the converter transformer tap changer at either station. The maximum bank capacity shall not exceed 1000 MVA. Main results of this study are applied in the design and consultant of UHVDC transmission project.