Performance Evaluation of Practical REBCO Coated Conductor Tapes for Superconducting Wind Power Coils

A Korean-type large scale floating offshore wind power system with a superconducting generator is the result of an innovative wind power project to develop high-temperature superconducting coils, a test facility, an offshore floating system, and network connection technologies. The 10 MW-class floating offshore wind power system utilizes a superconducting generator fully supported by Korea Electric Power Corporation. Large-scale applications of rare-earth barium copper oxide (REBCO) coated conductor (CC) tapes, particularly in superconducting wind turbine generators, must encompass high generation efficiencies and low-weight designs; they can do so by utilizing the high performance of REBCO CC tapes at cryogenic temperatures and under magnetic fields. Performance evaluations of the CC tapes are carried out by investigating the stress and strain dependency of I_c including irreversible degradation region under an external magnetic field. Generally, under a magnetic field, the I_c degradation behavior may be different from the results obtained at self-field and dependent on the fabrication processes and materials of the practical CC tapes. In this study, electromechanical properties such as I_c degradation behavior and the irreversible limits of three commercially available REBCO CC tapes were examined using uniaxial tension tests at the expected operating conditions, 35 K and 2 T. Results were compared to those obtained at 77 K and in a self-field.