Abstract:[Abstract] The ice-caused conductor galloping is a weather hazard which can deal harm to the operation of the power system. By analyzing the characteristics of synoptic situation, atmospheric stratification and the variation of cloud hydrometeor during the ice-caused conductor galloping episode during January 25th~29th, 2018 in the middle and lower reaches of the Yangtze River, the synoptic cause of the episode was investigated. Based on the WRF model coupled with the Ice Acceleration forecast system (IFAS), the temporal and spatial distribution of the wire icing thickness and the high risk area of conductor galloping were simulated. The conclusions are as follows: 1) The cold air mass mixed with the southwesterly warm air in the middle and lower reaches of the Yangtze River, where the temperatures from the surface to 700hPa were all below 0℃. The freezing rain process was driven by the “supercooled warm rain mechanism”. 2) The simulations show that the precipitation type at the ground change from “solid phase” to “mixed phase” and then to “solid phase” again during the time period of wire icing, which show good agreement with the observation. 3) By using the WRF model coupled with the IFAS, the simulated spatial distribution of the wire icing thickness was consistent with the observed freezing rain area. The simulated maximum ice thickness was also proved by the observation. 4) By coupling the AFWA scheme with WRF, the high risk area of conductor galloping was estimated by the simulated ice thickness and the instantaneous wind speed, which matched well with the observation from the State Grid. The results show that the temporal and spatial distribution of wire icing can be indicated from the simulated wire icing thickness, especially in the high risk areas of conductor galloping, which has significant practical value to the forecast and loss reduction of conductor galloping.