Development of a 45 kVA Single-Phase Model HTS Transformer

This paper presents design and test of a single-phase HTS transformer with capacity of 45 kVA operated in liquid nitrogen of 77 K for primary/secondary voltages of 2400/160 V. The windings were wound by stainless steel-enforced multifilamentary Bi2223/Ag tapes. The structures of primary and secondary windings are solenoid and double-pancake respectively. The gas-cooling current leads of secondary windings were chosen in order to reduce heat input. Cryostat is made from electrical insulating materials with room temperature bore for iron core made of the commercial Fe-Si steel. Fundamental characteristics of the transformer are obtained by standard short-circuit and no-load tests. The AC losses were calculated and measured by calorimetric method with a mass flow meter of nitrogen gas at room temperature. The performances of the transformer in accidental cases of sudden short-circuit and lightning impulse were also tested