Progress in development of a nanocomposite stator winding insulation system for improved generator performance

Abstract

Fundamental research program had been started to utilize silica nanotechnology to improve the electrical and mechanical properties of generator stator winding insulation. When tested at 0.6 m long tube-like specimens with original epoxy-mica insulation system the new SiO 2 nanocomposite insulation shows an electrical lifetime curve with a smaller sloop compared to the established winding insulation resulting in substantial improvement of lifetime at rated and operational electrical stresses. As next development step original stator bars with typical design parameter for hydro generators were fabricated. Voltage endurance tests at different stress level were performed to obtain electrical lifetime curves. First results demonstrate significant longer lifetime of nanocomposite compared to the actually used insulation system. The use of SiO 2 nanoparticles in epoxy-mica insulation will lead to a more efficient stator winding insulation system, which improves the specific power output on one hand and is tailored to the new highly flexible grid demands without reduction on lifetime on the other hand.