The fast development of wind power generation brings new requirements for wind turbine integration to grid. In order to improve the lower voltage ride through(LVRT) capability of fixed speed induction generator(FSIG) in wind power generating systems, the mathematic model of FSIG, supercapacitor(SC) and converter is built in DIgSILENT in this paper. A control strategy for FSIG and SC based on wind farms is proposed to enhance the terminal voltage of point of common coupling (PCC) after the clearance of an external short circuit fault. The simulation results show that the terminal voltage of PCC can be significantly improved when there is extra active and reactive power compensation available from SC.