With the Wuhan-Guangzhou high speed railway traction substation as the research background, the effect of high-speed railway traction power supply system on real-time power grid operation was studied, and PSCAD was applied to build suitable traction power supply simulation system for high-speed railway. Jiles-Atherton ferromagnetic hysteresis principles were employed to establish transient model of the V/v traction transformer. The piecewise linear U-I curve of UMEC model was equivalent to the saturated characteristics of the iron core, and then, no-load closing simulation was done. On this basis, simulation of single-phase short circuit fault and switch-in with load was done in time of three-phase short circuit fault in line side. The simulation results verify the practicality and validity of the traction transformer's transient model and traction power supply simulation system, which provides a reliable theoretical basis for the related operation departments.