New energy power generation technology gradually occupies an increasingly large proportion of power system. In order to achieve the stability of power system safe operation, it is necessary to understand the impact of system failures. The short-circuit current calculation is completed according to the crowbar action and related transient characteristics of doubly-fed induction generation. By establishing a doubly-fed induction generation model, and using the crowbar protection during a three-phase short-circuit fault, the dynamic changes of the internal mechanism of the wind turbine are analyzed, and the changes of the stator and rotor flux linkage during the fault are accurately calculated, to complete the new three-phase short-circuit current calculation method when the crowbar is in motion. Finally, a simulation is carried out by PSCAD/EMTDC, and the accuracy of the calculation method is tested by Matlab. At the same time, according to the low voltage ride-through capability of the wind farm and the characteristics of the current protection device, a low voltage ride-through protection scheme for a doubly fed wind farm is proposed. The scheme helps complete the protection of the line according to the voltage change requirements of the low voltage ride-through capability and the size of the short circuit current so that the wind field voltage can restore in time and maintain the grid-connected operation after clearing the fault. To a certain extent, it can cope with the delay problem of the low voltage ride-through capability.