Abstract As the traction load of electrified railway belongs to high-power nonlinear single-phase load, it will bring power quality problems such as harmonics and three-phase unbalance to the power system after being connected to the power grid, which is not conducive to the safety and economic operation of the public power grid. Therefore, it is necessary to evaluate the impact of the electrified railway operation under different conditions on the power quality of the system substation. In this paper, combined with an electrified railway transformation project of the power grid, an ETAP-based simulation model for electrified railway access to the power grid is established, which can quickly assess the power quality impact of the system-side substation caused by the traction load, and provide corresponding treatment measures for the electrified railway connection system program. At the same time, it can provide a basis for the electrified railway connection system scheme and equipment configuration.