Simulation Study and Experimental Analysis of Current Closure Overvoltage Caused by High Reactance on the AC Bus at ±800 kV Converter Station

When high reactance on AC bus in +/- 800kV converter station is switching, it will block the current and generate serious overvoltage, which may burn down the equipment. When AC bus in +/- 800 kV converter station is put into operation with high reactance, simulation calculation must be carried out to understand the situation of overvoltage caused by current closure, so as to arrange the restrictive measures and protect the equipment. In this paper, taking the AC bus high reactance of a +/- 800 kV converter station as an example, when the high reactance on the bus is disconnected, the overvoltage caused by the current closure is theoretically analyzed in detail, and the EMTS model of the system is established to simulate and calculate the overvoltage of the bus caused by high reactance. The results show that with the increase of the cutoff current value of the circuit breaker, the cutoff overvoltage generated by the shunt will be higher, even exceeding the required value of the regulations. A set of lightning arresters connected in parallel to the high-reactance side can effectively limit the interception overvoltage. During system debugging, field measurement data are collected, which is consistent with simulation data. The results provide valuable reference for the construction and operation of +/- 800 kV converter station.