used in high-voltage DC cable, the main prefabricated structure, the use of silicone rubber material in the factory injection vulcanization molding, reinforced insulation and shielding in cable accessories are molded in the factory as a unit or as several components, then put on the teated cable on-site installation.According to the characteristics of the DC transmission, optimize the voltage uniformity of electric field distribution of cable insulation and rubber insulation. The terminals are fitted with an interference fit on the cable insulation, elastic deformation theory calculation to ensure reasonable and stable interface pressure.According to utilized location of cable accessories can be divided into terminals and intermediate joints.The internal insulation of the terminal is controlled by a prefabricated stress cone, the outer insulation is a porcelain casing, a compound casing or an epoxy casing. Between the casing and the stress cone is generally filled with polyisobutylene insulating oil.When out of factory, the provision of silicone rubber pre-stress cone, tube, insulating oil and other components are assembled into the terminal on-site installation.The intermediate joint is made of a semi-conductive inner shield, main insulation, stress cone and semi-conductive outer shield of the joint, and is prefabricated into an integral joint preform in the factory. On-site installation, as long as put the overall  prefabricated connector into the cable insulation.