Insulation effect on thermal stability of Coated Conductors wires in liquid nitrogen

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Rubeli, Thomas^1 ; Dutoit, Bertrand^1 ; Martynova, Irina^2 ; Makarevich, Artem^2 ; Molodyk, Alexander^2 ; Samoilenkov, Sergey^2

Applied Superconductivity Group, Ecole Polytechnique Fédérale de Lausanne, EPFL-SCI-IC-BD, 1015, Switzerland^1

SuperOx, 20-2 Nauchnyi proezd, Moscow

117246, Russia^2

关键词: Coated conductors;    Exchange rates;    Nominal currents;    Novel techniques;    Quasi-static regime;    Resistive fault current limiters;    Silver coatings;    Temperature range;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012123/pdf
DOI  :  10.1088/1757-899X/171/1/012123

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Superconducting wires are not perfectly homogeneous in term of critical current as well as stabilization. In resistive fault current limiter applications this could lead to hot spots if the fault current is only slightly above the nominal current of the device. Increasing stabilization by using thicker silver coating for example may prevent this problem but this method implies longer wire length to maintain the same impedance during a fault. Very efficient cooling in another way to prevent hot spots, this can be achieved in nucleate boiling regime. Optimal insulation can be used to prevent film boiling regime, staying in nucleate boiling regime in a much broader temperature range. In this work a novel technique is used to monitor in real time the temperature of the wire during the quench. Using this method several increasing insulation thicknesses are tested, measuring for each the heat exchange rate to the nitrogen bath. Exchange rate measurements are made in quasistatic regime and during the re-cooling of the wire. SuperOx wires provided with different insulation thicknesses exhibit an excellent stability, far above a bare wire. On the other side, for very thick insulations the stability gain is lost. Re-cooling speeds dependency on insulation thicknesses is measured too.