Phase control technology of circuit breaker means that a circuit breaker closes or opens based on a special angle of voltage or current of power system to decrease overvoltage and inrush current during connecting or disconnecting the power equipment such as unloaded electric power transmission line

unloaded transformer

and capacitor.This paper discussed the principle of the phase control technology

with a focus on the analysis.of its applications in the breakers of 500 kV AC filters in Longquan converter station

Jiangling converter station

and Yidu converter station.