Abstract: In order to test the grid adaptability of MW-level and medium voltage direct-connected grid connected power generation systems such as photovoltaic power station, wind turbine and pumped storage plant, a 35 kV/3 MW grid simulator topology is introduced. However, limited by the sampling accuracy of potential transformer (PT), the direct use of PT output signal as the feedback of voltage regulator will seriously reduce the control bandwidth of the system and affect the dynamic and steady-state performance of the system output voltage. The frequency domain modeling is carried out according to the characteristics of PT, the influence of PT sampling on the system control is analyzed, and an improved control strategy is proposed. The output voltage of PT is used as the feedback of the effective value loop to ensure the steady-state accuracy. At the same time, the high-bandwidth and low-voltage instantaneous value sampling control is added to track the voltage command, so that the output characteristics of the power grid simulator can meet the requirements. The experimental prototype of 35 kV/3 MW power grid simulator verifies the feasibility and correctness of the control scheme.