Case study and mechanism analysis of sub-synchronous oscillation in wind power plants

Large-scale Doubly-fed induction generator-based wind power plants connected to series-compensated transmission system are facing the risk of sub-synchronous oscillations (SSOs). A regional grid recently suffered from a spate of SSO failures. This event seriously affected the safe and stable operation of the power grid. This particular case was analyzed in detail in this study. The characteristics of wind power SSO were summarized according to measured data. This study also examined the effects of the power grid and turbine control parameters through time-domain simulation and eigenvalue analysis using models of the actual power grid. Finally, this study presented the SSO mechanism.