Bode Stability Criterion Pertaining to SSR Analysis for Second Benchmark Model in DFIG Based Windfarm

Abstract

This paper presents impedance-based Bode stability analysis to investigate and mitigate the sub-synchronous resonance (SSR) of doubly-fed induction generator (DFIG)based series compensated network. A transmission line model is adapted from the IEEE Second Benchmark Model. The study system is developed by the impedance modeling of DFIG and network model. The Bode stability study of series compensated transmission lines is carried out at various compensation levels and wind speeds. Based on the stability analysis performed on the system, the system is unstable at high compensation levels of transmission lines and low wind speeds. Hence to mitigate SSR, an approximate damping gain is derived from the stability margins acquired in the Bode plot. The results indicate that the approach for calculating approximate damping gain provided in this study successfully dampens SSR under critical conditions.