Wind power ramp events have more and more influence on the wind turbine operation in the power system.Ramp events prediction becomes a new research topic at home and abroad.Research background，definitions and characteristics are summarized with respect to wind power ramp events.By considering frequency deviation values，a quasi-steady-state power flow calculation model is established including wind turbines.Frequency deviation value and slip correction value are introduced into the Jacobi matrix to calculate the power flow.Two types of indices，PRESF and APRESF，are adopted to forecast the ramp events.The proposed forecasting model is applied to 5-node system and 10-machine 39-node system for the validation simulation.Results verify the method with comparison and analysis.