JPS6423516A - Superconducting transformer - Google Patents

Abstract

PURPOSE:To reduce a loss of a winding to the utmost and to obtain a low-coat and small-sized superconducting transformer by a method wherein a part with the high magnetic-flux density of the winding is composed of a normal and the remaining part is composed of a superconductor. CONSTITUTION:A low-voltage winding 2 and a high-voltage winding 3 are wound on an iron core 1 via an appropriate reactance gap 4. An outer circumference side 2' at the low- voltage winding 2 and an inner circumference side 3' at the high-voltage winding 3 are composed of a normal conductor; the other windings situated at opposite sides of the reactance gap are composed of an oxide superconductor. By this constitution, the magnetic flux inside the windings is distributed in such a way that the magnetic-flux density becomes a minimum at a part opposite to the reactance gap 4 of the windings and that the magnetic-flux density becomes a maximum at a part of the reactance gap. The part with the high magnetic-flux density is composed of a normal conductor winding; because the critical-current density is large at the part with the low magnetic-flux density, a cross-sectional area of the superconductor can be reduced. In addition, the whole windings are kept at a low temperature until the superconductor displays a superconducting phenomenon, the resistivity in the normal conductor is lowered in accordance with the temperature; if, e.g, a copper wire is used and an operation is executed at the temperature of liquid nitrogen, a loss is reduced.