With the large-scale wind generation connected to power grid, it is of great significance to study the impact of wind generation on short circuit capacity of the system. In this paper, the location of short circuit fault is considered, and the short circuit current of fixed speed induction generator, Double-Fed induction generator and permanent magnet synchronous generator is analyzed. The expressions of short circuit currents and influencing factors on system of three different wind turbines are obtained at the failure time. A distribution network model containing three types of wind turbines is built, the output current of different wind turbines with the same capacity and its influence on the short circuit capacity of the system are simulated. The simulation results show that different wind turbines of the same capacity have different effects on the short circuit capacity of the system, the action of low voltage ride through protection devices will also have a great influence on the short circuit capacity of system.