Cause Analysis of Aging Ablation on Sheath of 110 kV Single Core High Voltage Cable

In recent years, the problems of aging ablation on high-voltage cross-linked polyethylene (XLPE) insulated power cable sheaths have occurred repeatedly, seriously affecting the stability of the grid system. In this paper, a case of aging ablation failure of 110kV cable sheath is analyzed. The heat aging caused by the metal sheath's circulating current may be one of the causes of aging ablation was proposed after considering the morphology of the ablation point and the actual operating environment of the cable. On this basis, a 110kv single-core cable stratified thermal resistance model was proposed to calculate the internal temperature of the cable, and a 110kV cable temperature field simulation model was established. The internal temperature distribution of the cable in the presence of circulating current was analyzed by a combination of theory and simulation. At the same time, the aging ablation experiment of simulated samples under different currents was carried out, and the aging ablation characteristics, aging ablation current values, aging ablation time and aging ablation temperatures were obtained. Finally, the simulated ablation samples were compared to the actual ablation point morphology by optical-microscopic. It is concluded that the morphology of them is very similar.