This paper proposes a probabilistic load flow method for wind-integrated power systems static security analysis in the system planning stage. By using the sensitivity matrix, branch outages are simulated through fictitious power injections at the corresponding nodes. So the method introduced in this paper could deal with branch outages, uncertainties of wind farms power injections in a unified procedure. A fast method combined Cumulants and Gram-Charlier Series expansion is applied to obtain the probabilistic distribution of nodal voltages and line power flows instead of the time-consuming convolution calculation. The static security will be analyzed afterwards using the probabilistic distribution. The simulation results using the IEEE 14-bus system are given to illustrate the feasibility and effectiveness of the proposed method.