Abstract:The icing on transmission lines is the key issue to cause snow and ice disasters during the winter. The on - line real - time ice - melting technology is an effective measure to relieve the snow and ice disasters. The accurate prediction of icing thickness on transmission lines due to freezing rain is the precondition of deciding the optimal ice - melting scheme. The simulated wire monitoring system and the on - site micrometeorology system are designed to simulate the conductor monitoring data and microweather station,and calculate the water content in the air according to the icing theory due to freezing rain. Based on grey system theory,GM( 1,1) model is applied to predict the water content,wind speed and rainfall in the air. The icing growth rate is figured out based on the predicted liquid water content,wind speed and rainfall. The simulation model of icing data is established by combining various actual monitoring data.