POWER TRANSFORMER WITH SUPERCONDUCTING WINDINGS

We have designed, constructed and tested a 330 kVA power transformer with superconducting windings. A niobium-titanium based superconducting wire optimized for AC applications was used in the windings. The transformer worked according to its design at rated power. The total heat input to the liquid helium bath at this power was 9.4 Watts, of which the AC losses dissipated in the windings were about one Watt per winding. The low voltage feedthroughs which had to carry 830 A(rms) at rated power worked adequately, The transformer revealed an apparent current limiting effect. This property can be utilized to Limit currents in a network for time periods 10-50 ms. A quench protection device was designed and incorporated in the test circuit.