This paper expands a nonlinear fuzzy based control strategy applied to a variable speed Wind Energy Conversion System WECS founded on Doubly Fed Induction Generator DFIG. As power network assists a high wind energy emergence, the studied WECS represents a wind farm WF of 500MW connected to the Grid and dispatched in such a way that it can contribute to grid frequency control with delivering a stable output equaling the power setpoint and keep a reserve for eventual increasing. Basing on the rotor currents maneuvering, the active power control is achieved independently to reactive power being adjustable according to grid request. The system is modeled using PSCAD/EMTDC linked to MATLAB for the fuzzy logic controllers FLC implementation. FLC are based on Takagi-Sugeno Fuzzy Logic Controller TSFC. Despite the wind speed fluctuations, results show a stable output following carefully a gradual change in power reference. Moreover, a THD analysis confirms the best quality of grid injected power.