Lécrevisse Thibault, Iwasa Yukikazu
Service des Accélérateurs, de Cryogénie et de Magnétisme, Institut de Recherche sur les lois Fondamentales de l'Univers, Commissariat à l'énergie atomique et aux énergies Alternatives, 91191 Gif-sur-Yvette, France.
Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
IEEE Trans Appl Supercond. 2016 Apr;26(3). doi: 10.1109/tasc.2016.2522638. Epub 2016 Jan 27.
In this paper, we report preliminary experimental results on protection study of two REBCO pancake coils based on the metal-as-insulation (MI) winding technique, a variant of the no-insulation (NI) winding technique, in which a metallic tape is cowound. Against the more-proven NI technique, our results demonstrate that the MI technique, too, is quite viable for HTS pancake coils with the following features: 1) nearly self-protecting;2) significantly smaller charging-delay time constant; and 3) better control of coil parameters. It also permits stable operation at 97% of a quench current. We present 77-K results of NI and MI pancakes: first, comparing the advantages and drawbacks of the two winding techniques and, second, dealing with stability and quench parameters. Finally, using a simple circuit model, we quantitatively show that metallic tape thickness has little detrimental effect on the self-protecting feature of the MI pancakes.
在本文中，我们报告了基于金属作为绝缘（MI）绕组技术对两个REBCO饼式线圈进行保护研究的初步实验结果，MI绕组技术是无绝缘（NI）绕组技术的一种变体，其中金属带是共绕的。与更成熟的NI技术相比，我们的结果表明，MI技术对于具有以下特点的高温超导饼式线圈也非常可行：1）几乎能自我保护；2）充电延迟时间常数显著更小；3）对线圈参数的控制更好。它还允许在失超电流的97%下稳定运行。我们展示了NI和MI饼式线圈在77K时的结果：首先，比较两种绕组技术的优缺点；其次，讨论稳定性和失超参数。最后，使用一个简单的电路模型，我们定量地表明金属带厚度对MI饼式线圈的自我保护特性几乎没有不利影响。
