Study on Electric Field Distribution Along V-type Composite Insulator String in Compact Transmission Line

The dislocation of grading ring occurs during installation and operation, which affect the operation performance of composite insulator. In this paper, the influence of four kinds of dislocation of grading ring on the electric field distribution of the composite insulator is studied. The influence of conductors and tower is also studied to ensure the relative accuracy of calculation. Based on the finite element method, the E-field simulation of the 3D model of the V-type composite insulator string in 500kV compact transmission line is carried out using COMSOL software. The whole-scale model considering conductors and tower is adopted because of more than 10% error without considering them. It is found that the electric field on the sheath surface will exceed the corona onset field strength only in case of reverse installation. The falling grading ring will make the E-field on the surface of the sheds exceed the corona onset field strength. Therefore, the dislocated grading ring should be replaced as soon as possible for safety. The research results of this paper provide simulation reference for the precaution of dislocated grading ring in the installation and operation.