Computation of Electric Field on High Voltage Polymeric Insulators Using Actual Model With Optimal Corona Ring Dimensions

Abstract

This article deals with the calculations of the electric field and the potential distribution of the polymer insulators of the HVTLs with the use of corona rings. The calculations are done when the insulators are stressed by power frequency voltage. The aim of this article is to investigate the effect of the optimal corona ring dimensions on the electric field and the potential distribution when the insulators are dried and wetted with salty pollutants dissolved in water droplets. The electric field of the outdoor polymeric insulator is inspected by the use of FEM software and the COMSOL multiphysics program. The 220 kV (RMS line voltage) actual models of the polymeric insulators are used in the study by the use of the 2D model. From the intensive study, it is concluded that the maximum value of the electric field in the absence of the corona ring reaches 13.89 kV/cm and decreases to 1.63 kV/cm (i.e., about 88% of its initial maximum value), in the case of using the optimal dimensions and location of the corona ring. In addition, the proposed corona ring dimensions to be used in high voltage polymer insulators have proven to be suitable in the case of the polluted insulator by salty pollutants dissolved in water droplets as well as the field reached very close to the E-field values that are recommended by the EPRI and IEEE specifications. In addition, this study helps in the development of corona ring dimensions to maximize the corona ring impacts on the polymeric insulators with respecting the industrial specifications. Finally, in conclusion, this study provides valuable insights into the optimization of grading rings for high-voltage polymeric insulators to prevent the failure of the 220 kV polymer insulators.