Analysis of AC Breakdown of Composite- Insulation depending on Gas Pressure and Solid Insulation Thickness

摘要

SF6 gas used widely as insulating component in electric power industry has excellent in insulation and arc extinguishing performance in gas-insulated switchgear. However, the concern about eco-friendly alternative gas is currently rising because SF6 gas is one of the main greenhouse gases. In this paper, dry-air and composite-insulation (dry-air + epoxy) as the alternative technology for SF6 gas insulation is studied. Under the gas pressure ranged from 0.1 to 0.6MPa, the breakdown voltage of dry-air is measured in AC electric field. The data of composite-insulation are ac acquired by changing the thickness of epoxy used in each composite-insulation under the same condition. As a result, in case of dry-air, the gas pressure needs to be compressed as about 3 times as that of SF6 to maintain the same dielectric strength. When the epoxy is applied by the thickness, the breakdown voltage of composite-insulation is increased by the side of dry-air. However, the difference by the thickness does not exist almost.