Impact of DFIG based wind generation on grid voltage and frequency support

Recent trends indicate replacement of fossil fuel drivenconventional synchronous generators from the existing power grid withinverter interfaced renewable energy sources in coming years. Asignificant portion of these renewable energy sources is predicted toinclude doubly fed induction generator (DFIG) based wind turbine. Thiswill cause a significant change in the grid dynamics, due to reduced systeminertia and the intermittent nature of wind power. The impact of gridintegration of DFIG-bases wind turbines on the grid voltage and frequencyhas been presented in this paper through rigorous simulation studiescarried out using the professional simulation software PSS/E. Thesimulation studies are carried out on a power grid network model thatincludes hydro, gas and wind generation under different voltage andfrequency contingencies or disturbances. Models of commercially availableDFIG-based variable speed wind turbines from top manufacturers havebeen used in the simulation studies. The effect of inertia, loss of generationsand loads on the system frequency, as well as the impact of different faultson system voltage are investigated and thoroughly analyzed. Furthermore,this study also includes the assessments of grid code requirements underfor high penetration of DFIG based wind turbines in the power grid.Critical analysis of the simulation studies reveal that DFIG-based windturbines are capable to contribute to system frequency and voltageregulation under different contingencies or network disturbances