Analyzing the effects of corona ring material and dimensions on the electric field distribution of 132 kV glass insulator string using 2-D FEM

Abstract

Insulators are highly important in high voltage transmission lines for their ability to regulate the amount of current flowing through the entire line. However, these insulators are vulnerable to electrical discharges such as current leakage, and corona under high voltage conditions. These phenomena cause the insulators to deteriorate overtime which makes them susceptible to breaking down. The paper analyses the effects of corona ring material and dimensions on the electric field distribution of the 132 kV glass insulators. The electric field distribution was calculated using a numerical method known as Finite Element Method where the analysis was done with its corresponding software, and the simulation utilizes a two-dimensional insulator string model. The results show that the installation of corona rings significantly improves the electric field distribution of the insulator string leading to a decrease in electric field of the highly stressed regions by 75%. Meanwhile, a lower installation height for the corona ring would improve the overall electric field distribution of the insulators. A higher installation height would cause the electric field to be less evenly distributed along the string. On the other hand, a higher ring diameter would worsen the field distribution where there was an increase in electric field of up to 54.1% at the bottom and the top of the string.