Optimization of EP/Al/sub 2/O/sub 3/-composites for SF/sub 6/ gas insulated power apparatus

Abstract

Support insulation in high voltage gas insulated substation (GIS) or gas insulated line (GIL) equipment must fulfill special requirements concerning the insulating, mechanical and environmental properties of the applied composite materials. This paper focuses on the performance reached by applying adhesion technology to increase the microscopic adhesion or bonding strength between Al/sub 2/O/sub 3/ filler surfaces and an epoxy matrix. The filler type and the medium filler grain size are varied to find an optimum in the mechanical crack resistance parameters. Besides the well-known mechanical, dielectric and electrical testing methods, a special partial discharge (PD) resistance testing method (Cigre II method) is applied to compare the PD resistivities of the investigated composites.