This paper introduces the DC deicer-SVC system in a pilot project in Shuanglong 500 kV Substation of Jinhua， Zhejiang Province. The principles， structures， functions and features of the controlled rectifier based DC deicer-SVC installation， deicing DC bus and mobile bus-connector are illustrated in detail. Supported by several proprietary technologies， this system can work in“deicer mode” or“SVC mode”， which can be switched by simple operations of external isolating switch matrix， without changing the internal main circuit and control program of the installation. This means the impact on power grid is minimized when the system changes work modes， or balance de-ices（circle de-ices） for conductors of different lines and different phases of one line in“deicer mode”.