风电-串补输电系统次同步谐振特性与风电机组数量及线路参数关系研究

RESEARCH ON IMPACT ON SUB-SYNCHRONOUS RESONANCE RISK FROM DFIG NUMBER AND GRID STRUCTURE IN GUYUAN AREA

针对双馈风电-串补系统次同步谐振特性,针对风电-串补系统次同步谐振问题,在RT-LAB中建立风电-串补送出系统等值模型,利用阻抗分析方法,对SSR风险与风电机组数量以及线路参数关系进行研究。得到主要结论:1)在不同风速下,均存在使系统阻尼特性最差的并网风电机组数量;2)线路串补度减小,系统的次同步谐振风险逐渐降低;3)线路长度越大,系统次同步谐振风险随风电机组数量的增加而增加。

In this paper,the equivalent model of wind farms and series-compensated power system in Guyuan is built in RT-LAB.Based on that model,the SSR characteristics of wind farms in Guyuan area under different DFIG numbers and line parameters are investigated through impedance method. The contributions to be included in the paper are as following:1)The relationship between SSR characteristics and DFIG number is nonlinear in Guyuan area. Under the condition of a given wind speed,there is certain number of DFIGs which will induce worst damping effect. 2)A higher compensation degree results in a less stable system. The SSR risk of the system increases with the increasing of DFIG numbers when the grid strength is high. The relationship between SSR risk and DFIG number is nonlinear when the grid strength is low.