The overhead ground wire is more likely to cause ice coating than the transmission line at freezing rain and snow condition in wither due to is absence of load current（except a very small inductive current）. While

in order to achieve the lightning protection effect

the overhead line must be earthed reliably through iron tower

which is contradictory to its insulation to earth at power on and ice melting condition. In view of a kind of 220 kV lightning protection and anti-ice disaster overhead ground wire system proposed in this paper

the rated output capacity of the DC deicing power supply is determined on the basis of describing its topological structure and operating principle

in accordance with the cable parameter of overhead ground wire and the hypothetical deicing scenario as well as by way of calculating DC deicing current and voltage. The structure parameters and of such core elements as full-bridge modular multilevel converter of the DC deicing power supply and the element selection are analyzed and calculated. Finally

the deicing simulation system model of 220 kV lightning protection and anti-ice disaster overhead ground wire based on modular multi-level converter is set up on the PSCAD platform and the control performance of the DC deicing power supply is verified.