Composite insulation technology for new compact 72/84 kV C-GIS

This paper presents a composite insulation technology for a new compact 72/84 kV C-GIS-cubicle type gas insulated switchgear. The dielectric characteristics of a composite insulation structure composed of low-pressure SF/sub 6/ and epoxy are shown. It is clarified that this structure is effective in increasing withstand voltages in nonuniform electric fields and that they can be further increased by applying solid insulator material having lower permittivity. These enable the clearances between poles and earth to be reduced. With this technology, the volume of the new C-GIS is reduced by 50% compared with conventional ones.