A simple protection evaluation method for no-insulation REBCO pancake coils during local normal-state transition

So Noguchi, Seungyong Hahn, Atsushi Ishiyama, Yukikazu Iwasa

研究成果査読

4 被引用数 (Scopus)

抄録

No-insulation (NI) and metal-insulation (MI) winding techniques are promising for enhancing the thermal stability of REBCO pancake coils, toward the practical use of nuclear magnetic resonance and magnetic resonance imaging systems. The NI and MI REBCO pancake coils showed high thermal stability in many over-current tests. However, a disadvantage is a charging delay due to low turn-to-turn contact resistance. Therefore, many researchers have tried to increase turn-to-turn contact resistance to overcome the charging delay problem. Meanwhile, a partial element equivalent circuit (PEEC) model can accurately simulate the over-current and charging/discharging tests of NI REBCO pancake coils in detail. Using the PEEC model coupling with thermal finite element analysis (FEA), the thermal stability was evaluated during a local normal-state transition. From the simulation results, it was found that a best range of turn-to-turn contact resistance existed to keep a high thermal stability during a local normal-state transition. However, the PEEC and thermal FEA method requires a substantial amount of time with complicated simulation approach. In this paper, we propose a simple mathematical formulation to obtain an appropriate range of turn-to-turn contact resistance during a local normal-state transition, supposing a worst cooling condition. The simple computation is easy to use and timesaving to roughly estimate the operation reliability of NI REBCO pancake coils.

本文言語English
論文番号045001
ジャーナルSuperconductor Science and Technology
32
4
DOI
出版ステータスPublished - 2019 2 15

ASJC Scopus subject areas

  • セラミックおよび複合材料
  • 凝縮系物理学
  • 金属および合金
  • 電子工学および電気工学
  • 材料化学

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