XLPE cables are widely used in urban transmission grids due to their excellent electrical properties. However, as the scale of the cables increases, their failure rates are gradually increasing. Long-term operation of the cable terminal in a rainy and humid environment, small cracks in the outer sheath, cold-shrinkable insulation tube, or irregular production process, and the remaining water stains on the surface of the XLPE insulation are not wiped dry, which will cause the cable terminal to become damp and reduce the insulation, and finally threaten the safe operation of the cable terminal. In order to study the distribution of electric field and temperature field inside the cable terminal under damp defects, this paper builds an electric-thermal field coupling model of XLPE cable terminal based on finite element simulation software, and explores the electric-thermal field distribution characteristics inside the cable terminal under damp defects. The results show that the location of the incoming water and the direction of the spread of moisture are the main factors affecting the electric field distortion. The dampness of the water near the stress cone will cause serious electric field distortion, which is easy to cause partial discharge, resulting in power loss, and local abnormal temperature rise, accelerate the aging of XLPE insulation, threaten the safe operation of the cable.

Cable terminal; Damp Defects; Electricity-thermal field; Finite element simulation;