Study on Transient Electric Field of Cable-Joint System under the Influence of Switch Operation

As a common cable accessory, cable joints are widely distributed in medium voltage cable systems. The insulation layer of the joint is mainly composed of multi-layer composite medium, which is the weak link of the insulation in the cable system. In recent years, many cases have shown that switching operation is an important factor leading to insulation breakdown of joints. This manuscript establishes a 10kV cable-joint simulation system by finite element method, and calculates the transient electric field distribution when the system is affected by switching operations. It is determined that the junction point of the three materials at the root of the stress cone is the most affected point on the interface between the cable and the joint, and the electric field intensity in the interface direction at this point reaches 2.08kV/mm.