Electric Field Distribution and Optimization Design of XLPE Cable Joints Under Typical Defect

The research on the electric field distribution of XLPE cable intermediate joints with typical defects is of great significance in preventing serious electrical accidents and ensuring the stable operation of power systems. Firstly, a two-dimensional axisymmetric model of XLPE cable intermediate joint is established by the finite element simulation software. Then, the electric field distribution in the case of typical defects such as gas gap and impurities is calculated. Finally, the changes of electric field distribution inside the cable joints before and after the optimization design are discussed in combination with the optimization design such as the improvement of the structure of the high-voltage shielding tube and the enhancement of the insulation layer. The results show that both gas gap and impurities can lead to significant electric field distortion. The presence of impurities has a more obvious effect on the electric field distortion. Increasing the radius of curvature of the terminal of the high-voltage shielding tube can be directed to improve the electric field distribution near the end. However, as the radius of curvature increases for farther from the end it may have the opposite effect, aggravating the electric field distortion. When the ratio of conductivity for XLPE and reinforced insulation is 1, the electric field distribution is better in the absence of defects. When defects are present, the conductivity ratio that gives the best electric field distribution changes, depending on the location of the defects, etc. After optimizing the conductivity of reinforced insulation, the improvement is obvious for the side close to the reinforced insulation layer and XLPE insulation layer. This research provides theoretical basis and data foundation for the optimal design of insulation of XLPE cable joints.