For doubly fed induction generator（DFIG），the crowbar protection is a commonly used method to improve the low voltage ride-through（LVRT）ability when there is a voltage sudden drop in the grid. The three-phase symmetrical short-circuit current characteristics of wind turbine driven DFIG with crowbar protection have been analyzed. Several effects have been taken into account in determining fault current from a wind turbine driven DFIG，including crowbar resistance，DC-side voltage and control strategy of grid-side converter in PSCAD/EMTDC. Approximation formulas of short-circuit current calculation are given on the basis of previous analysis. Finally，an equivalent impedance voltage source model considering the stator flux coupling is proposed，which helps further research for the protection configuration of distribution network with distributed wind generators.