Development of REBCO Power Transformers

Synopsis: REBCO superconducting power transformers, which are incombustible, lightweight and compact, are expected to have practical applications in equipment for substations and office buildings in urban areas. In recent years, there have been remarkable improvements in the performance of REBCO tape wires, which have the characteristic of a large critical current in highly magnetic fields. Their use is expected to reduce AC loss through the application of slit processing on the tape wire. Based on these advantages, the authors have developed element and system technologies of REBCO power transformers. Wire-scribing technology, coil-winding technology (for example, short-circuit characteristics), cryogenic technology, fault current-limiting (FCL) technology and a design study of a 66 kV/6 kV, 20 MVA transformer are examined.