Electric field calculation and analysis of HVDC cable joints with nonlinear materials

The design and manufacture of XLPE insulation HVDC cable joint is a challenge because the internal electric field distribution of the joint insulation can be affected by several factors and therefore is difficult to do accurate calculation. In this paper, the electric field distribution of cable joint fabricated with different silicone rubbers as reinforced insulation is calculated using COMSOL Multiphysics simulation. The influence of electrical conductivities of insulating materials on the electrical field distribution is investigated. The research results show that the electric field stress is unacceptably high in specific area if the joint is fabricated with common silicon rubber as insulation reinforcement. When the nonlinear conductive silicon rubber is used as reinforcing insulation for cable joint stress control cone, the electric field distribution profile becomes more uniform, and the maximum field strength locates inside the cable insulation layer. It is expected to achieve good performance XLPE HVDC cable joint by using nonlinear conductive silicon rubber for stress control cone insulation.