Comparison of permittivity gradient in resin injected and simulated cone-shaped spacers

Functionally graded materials are at the cutting edge of material technology. They will enable high efficiency and downsizing of apparatus leading to energy conservation in the power sector. Spacers with graded relative permittivity enable a decrease in the diameter of gas-insulated switchgears. Distribution of epoxy-based composite materials (resins) with different permittivities dominate the permittivity gradient in spacers. This paper compares resin injected spacers with simulation. High-permittivity resins, mixtures of high/low-permittivity resins at various mixing ratios, and low-permittivity resins were continuously injected to form spacers. In these spacers, both experiment and simulation showed similar tendencies of resin distribution and demonstrated permittivity gradients. Moreover, the high-permittivity resins were localized on the outlet sides rather than the inlet sides in both experimental and in simulation, and the simulation showed a stronger localization behavior than in the experiment.