The characteristics of static voltage stability in a large-scale wind penetration system are different from that of normal load center.The unique static voltage collapse phenomenon in large-scale wind penetration system is demonstrated based on PV curves.To control the static voltage stability，a calculation method of transfer capability limit is illustrated based on sensitivity analysis.Effective short circuit ratio（ESCR）is also proposed to evaluate the voltage stability of wind power integration system.The proposed methods and ESCR metric have been proved to be practical in a real system and can be used in the system operation and planning.