Flashover performance of ice-covered post insulators with booster sheds using experiments and partial arc modeling

The main objective of this paper is to present a new analysis, founded on partial arc activities, for evaluating the flashover performance of EHV post station insulators equipped with booster shed (BS) under heavy icing conditions. Based on observations from ordinary and high-speed cameras, novel discussions on partial arc characteristics, ice-free leakage distances, and flashover arc path were presented. Moreover, innovative axisymmetric simulations of partial arcs were implemented by using COMSOL Multiphysics™ in order to calculate their effects on potential distributions during the flashover process of the 4-, 5-, and 6-BS configurations. Simulation results of the BS configurations showed a redistribution of voltage drops along the air gaps after the appearance of the partial arc along the first air gap. This redistribution of voltage drop leads to the occurrence of partial arcs along the other air gaps which may somewhat explain occurrence of the flashover. The presented experimental and simulation studies can provide better designs for practical application of booster sheds.