SSR in Double-Cage Induction Generator-Based Wind Farm Connected to Series-Compensated Transmission Line

Series compensation of transmission networks is being increasingly considered for integration of large wind farms to transfer bulk power. This paper presents the potential of subsynchronous resonance in large wind farms based on double-cage induction generators connected to a series-compensated line. A detailed linear state space model is presented for the wind plant and the transmission system. Eigenvalues are determined for a wide range of series compensation levels for various sizes of wind farms as well as a wind farm producing different power outputs. The potential of SSR involving both induction generator effect and torsional interaction is investigated in-depth. Eigenvalue analysis results obtained through Matlab simulations are validated by detailed electromagnetic transient simulation using PSCAD/EMTDC software. Studies are conducted for different commercially available double-cage induction generator-based wind turbines. SSR analysis in a realistic wind farm with identical wind turbine generators subjected to different wind speeds, and different sizes of wind turbine generators subjected to same wind speed are also carried out. It is shown that induction generator effect-based SSR can potentially occur for wind farms even at realistic levels of series compensation.