基于STATCOM的大规模双馈风电场次同步振荡研究

Research on the subsynchronous oscillation of large-scale doubly-fed wind farm based on STATCOM

针对大规模双馈风电场在无串补情况下发生的次同步振荡现象,文章在Matlab/Simulink中搭建双馈风电场无串补含STATCOM输出系统模型,分析其振荡特点。利用特征值分析法分析了风速、网侧控制器内环增益、线路阻抗、延时环节参数以及STATCOM控制模式对次同步振荡特性的影响,对风电场汇集点的短路比以及汇集地区STATCOM并入电网对于系统次同步振荡的影响也进行了仿真分析。仿真结果表明:在无串补的情况下,在双馈风电场无串补含STATCOM输出系统的次同步振荡的风险与STATCOM的控制模式、风速、延时环节参数、线路阻抗、网侧控制器内环增益有关;风电汇集点短路比越小,网架结构将会变得越弱,越易发生次同步振荡现象,STATCOM并网时通过改变控制方式及其参数对次同步振荡有抑制作用。

In order to solve the sub-synchronous oscillation phenomenon of large-scale doubly-fed wind farm without series compensation,a STATCOM output system model with no series compensation for doubly-fed wind farms is built in MATLAB/Simulink,and its oscillation characteristics are simulated and analyzed.The eigenvalue analysis method is used to analyze the effects of wind speed,inner loop gain,line impedance,delay link parameters and STATCOM control mode on sub-synchronous oscillation characteristics,and verify the simulation.At the same time,the short-circuit ratio of the collection point of the wind farm and the influence of the STATCOM in the integration area on the sub-synchronous oscillation of the system are also simulated.The simulation results show that in the case of no series compensation,the risk of sub-synchronous oscillation of STATCOM output system without line compensation in the doubly-fed wind farm is related to STATCOM control mode,wind speed,delay link parameters,line impedance,and network side controller.The inner loop gain is related;the smaller the short circuit ratio of the wind power collection point is,the weaker the grid structure becomes,the more likely the sub-synchronous oscillation phenomenon occurs.When the STATCOM is connected to the grid,the control mode and its parameters can inhibit the sub-synchronous oscillation.