Next generation insulation for high operating stress

Abstract

The accurate control of the combination of mica paper, appropriate resin, and accelerator are important contributors to the overall mechanical and electrical properties of the high voltage coil groundwall insulated with mica paper tapes and impregnated with a high temperature epoxy resin. This paper presents the results of the dielectric performance when using special designed mica tapes for vacuum-pressure-impregnated (VPI) groundwall insulation. The objectives are to develop a glass backed mica tape with higher dielectric properties than commercially available tapes. Custom tapes were developed; working with a number of tape manufacturers. These tapes were used to make up insulated test bars and the best performing tape was applied to full size coils. This paper reports the final results of this investigation to develop the next generation stator groundwall system.