Bottleneck of developing large-scale ReBCO adiabatic magnet and its solution

• 1、School of Electrical Engineering & Automation, Harbin Institute of Technology, Harbin 150080

Abstract：In the past decade, the performance of high temperature superconducting (HTS) - ReBCO coated conductor has made great progress, and it has become the most dazzling star among all superconductors. However, its practical application cannot match the excellent superconductivity. Even for the medical MRI superconducting magnet, it has not shaken the position of low-temperature superconducting (LTS) conductor. People can\'t help asking, what is the bottleneck that restricts the application of HTS coating conductor to large-scale adiabatic stable superconducting magnet? The paper first introduces the difficulties encountered in the development of high temperature superconducting magnetic energy storage (SMES) magnets, reviews the achievements in stability theory, protection strategy and performance degradation of HTS magnets. It is pointed out that the real bottleneck lies in the coil quality, i.e. whether the HTS coil can fully avoid producing isolated critical current density concaves in the coated conductor, that researching the HTS magnet protection need us to change habitual thinking of following LTS magnet protection. On this basis, the paper lists the various situations that may induce thermal quenches during excitation process or normal operation period, and gives the solutions respectively.

Keywords： HTS magnet coated conductor adiabatic stability SMES quench protection degradation