Abstract: The series current limiting reactor can effectively limit the short-circuit current of 500 kV voltage level, but it will affect the overvoltage level of the system after it is connected to the system, and further safety verification is required. Taking the 500 kV/90 kA current limiter demonstration project of Guangnan station as the background, the electromagnetic transient simulation software of EMTP is used to study the overvoltage of the 500 kV current limiting reactor itself and the power frequency overvoltage and operating overvoltage of the current limiting reactor to the system, the transient recovery voltage of the circuit breaker, etc., so as to ensure the safe operation of the system and equipment. The results show that the power frequency overvoltage of Shunde-Guangnan 500 kV transmission line in the case of load rejection without fault and load switching with single phase fault is within the allowable range, no matter whether the current limiting reactor is used or not. The switching overvoltage of the 500 kV Shunde-Guangnan line after the connection of the current limiting reactor does not exceed the allowable range of the standard, and the MOA energy consumption and current of the MOA in the substation and the limiting reactance station have a large margin compared with the design parameters.