Abstract A significant quantity of renewable energy equipment, including photovoltaics and wind turbines, will be connected to the grid instead of traditional synchronous generator sets. However, the significant percentage of renewable energy sources that have been integrated into the power grid will lead to the frequency safety problem of the power system. The decrease in system inertia can adversely affect the stability of the power system’s frequency. Therefore, the influence of the local low moment of inertia on the frequency stability of the power grid is analyzed from the static and dynamic perspectives, and the method of participating in the primary frequency modulation after the wind turbine is connected to the grid is studied by taking the variable speed constant frequency wind turbine as an example.