Segmental insulation design method for UHV DC overhead ground wires under ice-melting with normal working condition

Icing disasters on overhead ground wires of ultra-high voltage direct current (UHV DC) transmission lines, influenced by micro-meteorological conditions in frozen snow weather, have occasionally resulted in accidents like ground wire disconnection and tower collapse. To improving the ice-melting efficiency of the overhead ground wires with normal working conditions, a new segmentation method for ground wires under ice-melting condition by adopting the electromagnetic transient joint simulation was proposed. Based on environmental conditions, the voltage and capacity required for ice-melting were automatically calculated by adjusting the pulse trigger angle of the ice-melting device, and then the number of ground wire ice-melting segments was determined, thus leading to the proposal of a ground wire segmentation ice melting scheme. Simultaneously, the impact of ice thickness and wind speed on the ice melting voltage was analyzed, and the effectiveness of the segmentation method was verified by the actual ±800 kV transmission line. The results show that the proposed method can automatically determine the ice-melting voltage based on environmental conditions, significantly improving accuracy over traditional empirical formula method. Ice thickness greatly affects the ice-melting voltage. By considering actual environmental conditions, ground wire icing conditions, and parameters of the ice-melting device, rapid design of segmented insulation for overhead ground wires can be achieved.