Reduction of electric-field intensification inside GIS by controlling spacer material and design

This paper presents finite-element simulation to calculate electric-field distribution inside coaxial gas-insulated switchgear and lines (GIS and GIL) for different solid spacer configurations, namely, disc, conical and post spacers. Several troubles and systems’ outages have been reported worldwide due to insulation failures. Therefore, it is essential to minimize the electric-field intensification along their surfaces, especially at the triple point “electrode-spacer-gas”, and hence enhance their reliability and increase their lifetime. Finite-element-based OPERA-2D software was used to calculate electric-field distribution by studying the effects of solid spacer dimensions and relative permittivity, application of functionally graded material (FGM) and the use of spacers with metalized cavities and shields.