As wind power is widely used， more and more wind power generators will be considered in the unit commitment planning. This imposes new requirements on the traditional security constraints unit commitment（SCUC）. As wind power keeps fluctuating， it is more reasonable to be modelled as a region. Besides， the asynchronous generator used in the wind turbine is different from that of thermal generator. It absorbs reactive power so that the unit commitment（UC） model should use AC security constraints. The model is a nonlinear and mixed-integer problem. For the sake of computational efficiency， the problem will be decomposed into two layers. The upper-layer is UC without network constraints. The sub-layer is optimal power flow（OPF） problem with AC constraints and objective of minimizing the network loss. If some variables are out of limits， some new constraints shall be added to the UC and security constraints optimal power flow（SCOPF）. As induction generator is widely used， the method uses an reactive power-voltage model to avoid reactive power overflow issue. An IEEE 57-bus system with a wind power generator is used for testing this method. Simulation results show that the proposed method is effective.