Suppression of gas pressure and tank diameter of dry air GIS by combination of FGM spacer and insulating coating conductor

The combination of relative permittivity (εr) functionally graded material (ε‐FGM) insulating spacer and insulated coating high-voltage (HV) conductor has been developed to enhance insulation performance of gas-insulated switchgear (GIS) and gas-insulated transmission line (GIL) utilizing dry air as an alternative to SF6 gas. Previous studies investigated the effects of insulation improvements based on limited data and literature. However, in this study, more detailed data were obtained and investigated. An epoxy coating with a thickness of approximately 100 μm was applied to the conductor surface, and in combination with ε-FGM spacers, the LI-FOV was measured under the same conditions. The results showed that the LI-FOV increased by 27% at 0.4 MPa-abs and up to 28% at 0.6 MPa-abs compared…