Power grid fault will cause the frequency and voltage fluctuation of the nuclear power plant, which will directly affect the operation status of the coolant pump and the heat dissipation blade of the nuclear power unit. When the fluctuation degree exceeds the maximum allowable range of nuclear power equipment, may cause the nuclear power plant damage. In order to study the operation status of large-scale nuclear power plant equipment under grid failures, this article focuses on nuclear power plants in a certain area. A 500 kV grid model including pressurized water reactor(PWR) nuclear power plants is built on the PSCAD/EMTDC platform. The custom details of nuclear power plants are detailed The model includes reactor core, steam generator, steam turbine module, etc. The model can reflect the internal dynamic characteristics of nuclear power plant equipment in the event of a grid failure. By simulating the impact of voltage and frequency disturbances on nuclear power plants in the case of grid faults, the disturbance tolerance threshold for the safe operation of nuclear power plants is given, and equipment protection measures in the event of a three-phase short-circuit fault in the power grid are proposed, which is the fault ride-through of nuclear power plants. Further research on capabilities has laid the foundation.