Optimization of Permittivity Graded Spacer for Suppressing Metal Particles in AC-GIS

Contamination from metallic particles can critically compromise the insulating properties of gas-insulated switchgears (GIS). This paper introduces a bowl-shaped spacer with spatially varying permittivity (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\varepsilon$</tex>-FGM), optimized through a variable-density topology method, to suppress the electric field concentration at the triple junction and modify the axial field distribution near the spacer. The optimized <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\varepsilon$</tex>-FGM spacer achieves a 31% reduction in electric field strength at the triple junction and a 41% decrease in the maximum surface electric field. Additionally, the axial electric field near the spacer is effectively reversed, causing metal particles to move away from the spacer. The average particle velocity increases by a factor of 2 times. These findings highlight the potential of functionally graded dielectric materials in enhancing insulation performance in GIS and offer a novel approach to mitigating metal contamination in high-voltage equipment.