Electrostatic modelling of gas-filled voids and conductive particles in highly non-uniform electric fields

Wong, Timothy and Timoshkin, Igor and MacGregor, Scott and Wilson, Mark and Given, Martin; (2023) Electrostatic modelling of gas-filled voids and conductive particles in highly non-uniform electric fields. In: 23rd International Symposium on High Voltage Engineering (ISH 2023). IET Conference Proceedings . IET, GBR, pp. 1022-1028. ISBN 9781839539923 (https://doi.org/10.1049/icp.2024.0748)

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Abstract

The reliability of modern high voltage equipment strongly relies upon the prevention of partial (or complete) electrical discharges. Electric field enhancement, caused by defects and contaminants inside insulating materials, can play a major role in discharge initiation, potentially leading to the catastrophic failure of critical equipment. The problem is exacerbated when considering existing regions of nonuniform electric field, possibly caused by unintended metallic protrusions, surface roughness, and other high aspect-ratio features. In this work, gas-filled voids and conductive particles of spheroidal geometry were investigated under highly nonuniform field conditions. By employing an analytical methodology, the electric field distribution has been modelled around a spheroidal dielectric inclusion, subjected to a nonuniform electric field, and generated with a needle-plane electrode system. A systematic study was conducted to investigate the effects of inclusion type (gas-void or conductive particle); inclusion proximity to the HV electrode; inclusion radius; inclusion eccentricity; and needle curvature, on the enhancement factor of the redistributed field inside and outside of the inclusion. The results arising from this work further advances the understanding of insulation defects and contaminants near complex geometrical features, aiding the future development of high voltage power and pulsed power systems.