DC de-icing technology is an effective measure to solve the ice-cladding problems of extra-high voltage transmission lines. During DC de-icing process

the single-phase ground fault of transmission lines is easily caused by falling ice water. The fault location method is studied to ensure safe and reliable operation of the transmission lines and system. The DC de-icing system and the topological structure and control strategy of converter are described first

and a detailed simulation model of the DC de-icing system is built. Based on Bergeron model

the voltage profile along the line is analyzed at length and a novel fault location method is proposed to locate the single-phase ground fault of de-icing transmission lines under fixed-current control. PSCAD/EMTDC simulation software is used to simulate and test all kinds of single-phase ground faults. Simulation results show that the fault of de-icing transmission lines can be located quickly and accurately in time domain with the proposed method.