Development of A Superconducting Transformer for Rolling Stock

Abstract

Having undertaken studies into a lightweight and highly efficient superconducting transformer for rolling stock, we developed a prototype with a primary winding, four secondary windings and a tertiary winding using bismuth (Bi-2223) high temperature superconducting wire. Its primary voltage is 25kV, which is widely adopted as the catenary voltage on the world's high-speed lines. We adopted liquid nitrogen cooling, the weight being 1.71t excluding the refrigerator. The maximum output available to maintain superconductivity is 3.5MVA. This paper describes the transformer details and test results.