Evaluation on Quench Protection for No-Insulation REBCO Pancake Coil

Takahiro Oki, Aika Ikeda, Tao Wang, Atsushi Ishiyama, So Noguchi, Katsutoshi Monma, Tomonori Watanabe, Shigeo Nagaya

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

We have been developing a no-insulation (NI) winding technique to be used in both high thermal stability and high current density, which have a tradeoff relationship. This paper presents numerical and experimental studies on the thermal stability of an NI REBCO pancake coil by focusing on a quench protection scheme. In the case of an accident or a local normal-state transition, the power supply for the superconducting coil must be immediately shut down in order to ensure its safety. During the sudden discharging of a conventional insulated winding coil, most of the stored electromagnetic energy is dissipated by an external dump resistor connected across the coil terminals as a quench protection system. However, in an NI pancake coil, current flows in the radial direction in order to bypass the local normal-state area to the adjacent turns. The stored energy in the coil may be dissipated as Joule heat owing to the turn-to-turn contact electrical resistance. In this study, by using experiments and numerical analyses, we evaluated two transient behaviors during sudden discharging: the distribution of energy dissipation and the temperature increase in model NI REBCO pancake coils. We also evaluated the thermal behavior of the NI coil during a local normal transition.

Original languageEnglish
Article number7429748
JournalIEEE Transactions on Applied Superconductivity
Volume26
Issue number4
DOIs
Publication statusPublished - 2016 Jun

Keywords

  • High-temperature superconductors
  • no-insulation coil
  • partial element equivalent-circuit model
  • quench protection

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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