Development of a 6600 V/210 V kVA hybrid-type superconducting transformer

In this transformer, the low-voltage, high-current winding is made of liquid-helium-cooled superconducting wire and the high-voltage winding is made of liquid-nitrogen-cooled low-loss copper wire. The iron core is placed in a room-temperature environment outside the cryostat vessel. The cryostat vessel has a two-layer configuration of liquid-helium and liquid-nitrogen cooling vessels. The concept. design features, and measured characteristics of the H-SCT are described. Fundamental characteristics are obtained through short-circuit and no-load tests. The critical quenching current and in-rush current are also evaluated