The electrical connection of wind farm to power transmission line and power distribution line present certain consideration in design and practice.The higher percentages of wind power generation are being used in the network，the more substantial effect of the fluctuation may be resulted and therefore analysis on stability,reliability and grid connection is important for system engineers.Therefore the reliability and control strategies of new and existing power systems which contain wind power are needed to be re-examined.In this paper,the effects of different wind farm capacities to power gridwere analyzed，and the reason,model and correlative results are presented.