Sub-Synchronous Control Interaction studies between full-converter wind turbines and series-compensated AC transmission lines

Under certain conditions Sub-Synchronous Resonance (SSR) or Sub-Synchronous Control Interactions (SSCI) can cause damage or incorrect operation of wind turbines. This paper describes why SSR/SSCI behavior occurs, how simulation techniques can be used to assess these control interactions. The steady state stability of the Type 4 wind turbine is assessed using frequency domain modeling. A detailed PSCAD/EMTDC model is also described for analyzing transient behavior via time domain simulations. The applied controllers for a full-converter wind farm are shown to be immune to SSR/SSCI in the presence of series compensated transmission lines.