Abstract:In the power system, inrush current will appear while closing/opening breakers of capacitor or closing a no-load transformer. The inrush current may cause protection device a incorrect action or harmful effections to primary equipment. By closing/opening breakers at a appropriate phase angle, the controlled switching device can reduce the inrush current effectively. 14 transformers and 14 AC filters are installed in LuXi converter station, and for the purpose of reducing inrush current 28 controlled switching devices are installed. In this paper, the basic principle of controlled switching device is introduced, and the application and input/output circuit of the device based on detailed design diagrams is also analysed. For the problems occured in the station system commissioning, ideas of solution are presented in the paper. The improved ideas will provide reference methods for the application of controlled switching devices in the future engineering.