Characterization of Interface Defects in High Voltage Cable Factory Joints

With the development of high-voltage cable industry, it is necessary to use cable joints to make single cables connected to each other in order to realize the demand for large lengths of high-voltage cable lines. Extruded molded flexible joints (EMJ) are widely used in the connection of long-distance high-voltage cable lines, and the interface formed by its body insulation and restoration insulation is the key to ensure the effective continuity of the insulation. In this paper, the micro-morphology of the interface of the factory joints is characterized by scanning electron microscope (SEM), and it is found that there are a series of linearly arranged ripples at the interface, and it is verified by multi-physics simulation that the stress generated by the cooling and crystallization of the insulation results in the formation of ripples in the interface area. It is verified by multi-physics simulation that the stresses generated by insulation cooling and crystallization lead to the formation of ripples in the interface area, which indicates the mechanism of the interface prone to defects.