Electric field calculation and grading ring optimization of composite insulator for 500kV AC transmission lines

With finite element method, this paper established a static three-dimensional model to calculate the potential and electric field distribution of composite insulator for 500kV AC transmission lines. By changing the mounting height, diameter and caliber of the grading ring installed on the composite insulator, the electric field distribution of the insulator could be controlled visually. After analysis and comparison of the electric field strength on the surface of grading rings and the field distribution curves along the insulator with variable grading ring parameters, the reasonable grading ring configuration was recommended. It can improve the electric field distribution of the composite insulator and also reduce the electric field strength on the surface of grading rings and end-fittings. The conclusions of this paper have important engineering application value for 500kV AC transmission lines construction.