Calculation and Optimization of Electric Field of Insulators with Internal Grading Ring

Abstract

In recent years, the local temperature rise of composite insulators has become a serious problem. Research shows some of the insulators with local temperature rise have partial erosion in the core, while their outer sheath worked well. It is of great significance to study the electric field along the surface of the core. In this paper, a two-dimensional axisymmetric computational model was established for insulator strings of 500kV transmission lines to study the influence of internal grading ring and corona ring on the surface electric field of the core. It can be concluded that the internal grading ring greatly homogenized the field strength. The position and size of the peak point of the surface electric field of the core can be adjusted by changing the position of the internal grading ring. The position of corona ring affects the value of peak point of electric field. When the relative position of the two is fixed, the change of the overall position has little effect on the peak value of the field strength.