Research on the Impact on Sub-synchronous Resonance Risk from DFIG Number and Series-compensated Degree

Abstract

Sub-synchronous resonance (SSR) occurred in the power system with both Doubly Fed Induction Generators (DFIGs) and series-compensated lines. Existing paper discovered the nonlinear relationship of SSR damping and the number of DFIGs. 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 results show that: 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 series-compensated degree results in a less stable system.