Improved methodology for damping sub‐synchronous oscillation in a series‐compensated DFIG‐based wind farm

Abstract

AbstractThe interaction between the wind farm and the series‐compensated transmission line may lead to the sub‐synchronous oscillation (SSO) phenomenon which affects the system stability and equipment safety. Among the presented methods for damping the SSO phenomenon, the supplementary damping controller (SDC) is the most prevalent method because of its low cost, effectiveness, and simplicity. In all previous studies, one input control signal is fed to the SDC for mitigating the SSO. Here, two input control signals (active power and reactive power deviation) are applied to the SDC for enhancing the system stability and damping the SSO quickly. The ability of the proposed method for damping the SSO has not been investigated before. The proposed SDC is embedded into the q‐axis of the rotor‐side converter (RSC) inner current loop. The modified IEEE first benchmark model (FBM) is used to analyze the performance of the proposed method under different compensation levels, variable wind speeds, and sub‐synchronous control interaction (SSCI). Small‐signal stability using the eigenvalue approach is carried out, where the impact of the proposed method on sub‐synchronous mode, and super‐synchronous mode is investigated. The results successfully prove the superiority of the proposed method for damping the SSO under various operating conditions compared to some previous methods, where the least overshoot and faster convergence have been achieved by the proposed method in all studied cases.