GAS-INSULATED SWITCHGEAR

PROBLEM TO BE SOLVED: To enhance the dielectric strength by making a closed container of aluminum or an aluminum alloy, forming an alumite layer of a specific thickness or more on its internal surface and forming an insulating film of a specific thickness or more on the surface of the alumite layer. SOLUTION: On the surface of the closed container of a gas-insulated switchgear an alumite layer 12 of a thickness >=1 μm is formed, and on its surface an insulating film 13 of a thickness >=10 μm is formed Consequently, protrusions of a closed container 11 generated by scratches, etc., are dissolved and smoothed when alumite processing is performed, and the electrolytic distribution of the internal surface of the closed container 11 is improved by the formation of the insulating film 13 on the surface of the alumite layer 12. When a conductive foreign matter 9 exists in the closed container 11 and partial discharge is generated, supply of free electrons to the foreign matter 9 is interrupted by the insulating layer of the insulating film 13 and the alumite layer 12. Accordingly, charging of the foreign matter 9 is suppressed, and the buoyant force of the foreign matter 9 does not become large. Consequently, it becomes possible to suppress lowering of the dielectric strength.