The intermediate joint of the cable is prone to defects during manufacturing or installation, which deteriorates its insulation performance. The molded joint has improved the compatibility at the interface to some extent, however, there are still possible defects in some positions of the joint. In order to study the impact of defects in the molded joint of high voltage cable on electric field distribution, the article firstly analyzed three typical defect types of the molded joints of 220 kV polypropylene cable, then established the 3-D simulation model based on COMSOL simulation software, and finally calculated the electric field distribution. The results show that all three kinds of defects will lead to different degrees of electric field distortion. The enhanced electric field strength at the defect site of the joint may accelerate insulation deterioration or even lead to early electrical failure.

polypropylene cable; molded joint; defects; electric field distribution