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Fluorescent thermal imaging of a quench in insulated and non-insulated REBCO-wound pancake coils following a heater pulse at 77 K

Gyuráki, R.; Schreiner, F.; Benkel, T.; Sirois, F.; Grilli, F.

Abstract:
High temperature superconductors (HTS)-wound coils are being developed for use in motors, generators as well as magnet applications. Determining the stability and safe operating margins of such coils still poses challenges. While the recently introduced no-insulation winding method provides a remedy for many problems, it comes with its own limitations. For comparison, we have wound two pancake coils from HTS coated conductors with the insulated and non-insulated winding techniques. Both coils were coated with a fluorescent, temperature-sensitive coating, which allowed monitoring the surface temperatures during operation. The coils were cooled to 77 K via a combination of conduction and gas cooling, and their electrical and thermal behaviour was observed in operation. Here we present the normal transition of both coils caused by an artificially introduced instability due to a surface-mounted, resistive heater element. In the insulated coil, the localized disturbance caused a local transition of the superconductor to the normal conducting state, triggering a thermal runaway. Merely the turns in contact with the artificial disturbance heated up, while the rest of the coil remained in the superconducting state. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000119119
Veröffentlicht am 07.05.2020
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Technische Physik (ITEP)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 03.2020
Sprache Englisch
Identifikator ISSN: 0953-2048, 1361-6668
KITopen-ID: 1000119119
HGF-Programm 37.06.02 (POF III, LK 01) New Power Network Technology
Erschienen in Superconductor science and technology
Verlag IOP Publishing
Band 33
Heft 3
Seiten Art. Nr.: 035006
Vorab online veröffentlicht am 04.02.2020
Schlagwörter thermal imaging, HTS, non-insulated coil, insulated coil, fluorescent thermal imaging
Nachgewiesen in Web of Science
Scopus
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