Performance of GIS epoxy insulators and related tests

Gas-insulated switchgear (GIS) are used up to a nominal voltage of 1100 kV. One of the main GIS components are the solid epoxy insulators which are subject of ageing under mechanical and electrical stresses. Optimized insulator design based on calculations/simulations and intensive mechanical and electrical testing of insulators during research and development and manufacturing are key issues for a trouble-free life of GIS. Results from high-voltage long-duration tests on real-sized insulators are described in comparison with the return of experience from a GIS which was in service for more than 37 years.