This paper proposes a fault-tolerant control scheme to evaluate and enhance the performance of wind turbines using a nonlinear sliding mode control scheme. The wind turbine benchmark model with actuator faults in the pitch system is considered and the sliding mode control technique is designed and implemented to enhance the stability and reliability of the wind turbine system. The simulation results of implemented sliding mode controller on a benchmark wind turbine model are also compared with LQR and PI control schemes to show the efficiency of the proposed fault-tolerant scheme.