Thermal-quench behavior of non-insulated high-temperature superconducting (HTS) racetrack pancake coil with cooling channels through the epoxy surface

Mtangi Mohamed Mussa, Hyun Sung Noh, Dawool Kwon, Yunyeol Ryu, Yeon Suk Choi, Haigun Lee

    Research output: Contribution to journalArticlepeer-review

    6 Citations (Scopus)

    Abstract

    The high-temperature superconducting (HTS) racetrack pancake (RP) coil is recommended to be used as a field coil in rotating machines such as generators and motors. Epoxy impregnation is normally required in the field coil to protect it against mechanical stresses due to the variation in the magnetic field and to enhance its mechanical stability to withstand rotor vibrations. However, the thermal conductivity of epoxy is very low compared with that of HTS. Consequently, when quenching is induced in an epoxy-impregnated coil, the Joule heating is poorly dissipated outward because of the absence of thermal drain to dissipate the heat in liquid nitrogen (LN2), which damages the coil through heat accumulation. We designed cooling channels (pores) through the surface of an epoxy-impregnated coil to boost the circulation of LN2 in the coil during the cooling process and to improve the operation of the coil during quenching. In this study, cooling-down and quench tests were performed on the epoxy-impregnated RP coils to investigate the effect of cooling channel on the thermal-quench characteristics of the RP coils. Moreover, the minimum quench energy and normal-zone propagation velocity of the hotspot induced in the coils were discussed on the basis of the quench-test results.

    Original languageEnglish
    Article number104131
    JournalResults in Physics
    Volume24
    DOIs
    Publication statusPublished - 2021 May

    Bibliographical note

    Funding Information:
    This work was supported by the Korea Basic Science Institute under Grant No. D010200 and in part by the Materials and Components Technology Development Program of KEIT [10053590].

    Publisher Copyright:
    © 2021 The Authors

    Keywords

    • Cooling channels
    • Epoxy impregnation
    • HTS racetrack pancake coil
    • MQE
    • NZPV
    • No-insulation coil
    • Stycast 2850 FT
    • Thermal/electrical stability

    ASJC Scopus subject areas

    • General Physics and Astronomy

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