Reduced order modeling of wind farms for inclusion in large power system simulations for primary frequency response application

A reduced order linearized dynamic model for a variable speed wind farm (WF) is introduced in this paper. The individual turbine model for the WF is a two mass model and assumed to be operating under maximum power point tracking control strategy. This paper studies pitch based deloading of WF and a control scheme to emulate inertia and support primary frequency control using a dynamic linearized model. The model is linearized between the wind velocity and system frequency vs power output of farm. The model is validated against an actual nonlinear DFIG based WF simulated in Dig-SILENT Power Factory with efficient simulation performance indices. The main advantage of this reduced order model is its capability to predict dynamic frequency response and thus allows frequency response based control strategy for the WF. The savings in computational efforts are significant, with little loss of accuracy.