DEVELOPMENT OF A PERFLUOROCARBON LIQUID IMMERSED PROTOTYPE LARGE POWER TRANSFORMER WITH COMPRESSED SF6 GAS INSULATION

A prototype of three phase non-flammable, large power transformer has been developed. It uses non-flammable perfluorocarbon liquid as both a coolant and an insulating material for windings, and compressed SF6 gas as the insulation from the outer windings to the tank. Using cooling and insulation models, the cooling and insulation characteristics of the disc windings were clarified. Stress analyses and the pressure tests of the transformer tank were carried out, to evaluate its mechanical characteristics. Finally, a prototype of 275kV 100MVA three phase transformer was developed, and its excellent performance was confirmed.