This paper explores the possibility of occurrence of subsynchronous resonance (SSR) in a system comprising a conventional induction generator-based Type-2 wind farm connected to a series-compensated line. The induction generator is equipped with rotor resistance controller (RRC) which cuts in when wind velocity exceeds the rated. A comprehensive small-signal model of the system that includes the controller is developed and used for the analysis. The subsynchronous oscillations considered are due to self-excitation, torsional interaction and transient torque amplification. The test system considered is IEEE first benchmark model (FBM) for subsynchronous resonance with synchronous generator replaced by aggregated wind farm. Eigenvalue analysis is employed to evaluate system-wind farm interaction. The analysis includes the impact of series compensation level, wind velocity and wind farm size on SSR. Eigenvalue analysis is validated electromagnetic transient simulations and fast Fourier transform (FFT) analysis. The contributions of this paper are: Type-2 wind farms are more susceptible to self-excited oscillation at normal (practical) compensation levels, mitigation of these self-excited oscillations by the STATCOM controller that is employed at the point of common coupling for reactive power compensation, thereby avoiding the necessity of other controllers (FACTS).
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