Development of REBCO Superconducting Transformers with Current Limiting Function

RE1Ba2Cu3O7-≏(RE: Rare Earth, Y, Gd and so on, REBCO) superconducting tapes have high performance in critical current density, Jc, property even in high magnetic field and at liquid nitrogen temperature. We have proposed the ac loss reduction method of REBCO superconducting tape, which are the combination of a laser–scribing into a multifilamentary structure and a special winding process. Using the ac loss reduction technique, we could realize REBCO superconducting transformers with the advantage of light weight, compactness and high efficiency in comparison to conventional one. Further we aim to add a current limiting function to REBCO superconducting transformers. Recently we manufactured a 10kVA four-winding transformer with REBCO tapes. We carried out a sudden short circuit test and investigated the response against the fault excess current. We developed a numerical analysis program so as to quantitatively simulate the phenomena taking into account of a flux-flow resistance. As a result, it was shown that the whole of the REBCO winding did not shift to normal state even though the current exceeded the critical current all over the length. In this paper, we report the outlines.