Heat transfer properties of a conduction cooled prototype LTS pulse coil for UPS-SMES

Akifumi Kawagoe, Hideyuki Yamamuro, Fumio Sumiyoshi, Toshiyuki Mito, Hirotaka Chikaraishi, Tomosumi Baba, Mitsuhiro Yokota, Yoshitaka Morita, Hideki Ogawa, Tsutomu Henmi, Kagao Okumura, Ryo Abe, Masataka Iwakuma

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


We have been developing a 1 MW, 1 sec UPS-SMES for the protection of production lines of an industrial plant or large-scale experimental devices such as a fusion device from a momentary voltage drop and an instant power failure. A conduction cooled prototype LTS pulse coil of 100 kJ class was developed as a key component of the UPS-SMES. The prototype coil has demonstrated excellent thermal characteristics during cooling and exciting tests. In this paper, measurements of the temperature in the coil during experiments and thermal analysis by using two-dimensional finite element methods were compared to clarify the high heat transfer properties of this prototype coil. This coil was wound with a NbTi/Cu Rutherford cable, which is extruded with aluminum. In order to realize the conduction cooled LTS pulse coil, FRP with polyethylene fibers (Dyneema FRP) and Litz wires were used as spacers. Dyneema FRP improves the heat transfer from layer to layer in the windings. Litz wires increase the heat transfer from turn to turn in the windings and enable conduction cooling of the coil by attaching the end of the Litz wires directly to the cold heads of the cryocoolers. It was clarified that these spacers were very effective and the coil has a large stability margin in terms of the design values.

Original languageEnglish
Article number1642926
Pages (from-to)624-627
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Issue number2
Publication statusPublished - Jun 2006

All Science Journal Classification (ASJC) codes

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


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