Simplified dynamic models of variable speed wind turbines for frequency regulation studies

This paper discusses the application of reduced order dynamic models of deloaded wind turbine generators (WTGs) for primary frequency regulation studies. Both nonlinear and linear models have been investigated to analyze the inertial response capability of WTGs. The non-linear model is valid for a wide range of wind speeds. At constant wind speed, the non-linear model is linearized to obtain a first order transfer function linking the system frequency and WTG power output. The transfer function is shown to effectively emulate the deloaded WTG behavior like its non-linear model. In the context of wind farms, the non-linear model is further extended to study the effects of spatial smoothing.