Transformers without an iron core using a supercooled Al conductor

Using a supercooled conductor as windings in a large power transformer, it should be expected that the transformer is lower in loss, smaller in size and lighter in weight. For such a conductor, Be (2×10^<-10> Ωm at 77°K of the liquid nitrogen), Al (3×10^<-11> Ωm at 20°K of the liquid hydrogen) and Nb (superconducting at 4.2°K of the liquid helium) can be cited but Nb and Be are less useful by the reason of its quenching in the leakage flux and its large magnetoresistance effect respectively. In this paper, a coreless transformer is considered and a supercooled Al conductor is employed in it. The merits of this transformer are that 1. there is not such a catastrophic heat generation as in a superconducting transformer and so fast circuit breaker is not necessary 2. simultaneously, to stop operating the transformer for a long time owing to such heat up can be avoided 3. it uses an inexpensive hydrogen gase 4. the dewar vessel is simplified because the transformer has not an iron core The rough calculations on a 3-phase 190MVA transformer show that this coreless transformer is about 25% reduction of the conventional value in weight and 39% reduction in volume.