Investigation on Irregular AC Losses in Large Superconducting Coils

大型超导线圈不规则交流损耗的研究

基本信息

批准号：
15360491
负责人：
HAMAJIMA Takataro
金额：
$ 5.76万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360491/
关键词：
AC loss Irregular coupling loss Cable in conduit conductor Long time constant Sub-cable Displacement Contact resistance Strand locations ケーブル・イン・コンジットケーブル・イン・コンジット(CIC)導体

项目摘要

It is found that irregular AC losses in cable-in-conduit superconductors cannot be estimated from short conductor sample test results. Current loops, which must be irregularly formed in the cable, decay with the long time constants, and hence enhance the AC losses.We propose a mechanism forming the long loops. The cable is composed of several staged sub-cables. If one strand on the surface of a sub-cable contacts with the other strand on the surface of the adjacent sub-cable, the two strands should encounter each other again at LCM distance of all staged cable pitches, and thereby result in forming a pair of a long loop. The time constants of these loops are fundamentally described as ratios of their inductances to their contact resistances.In order to estimate the time constants τ=L/R of the long LCM loops, we measured the cross contact resistance between the two strands in LHe. The test results showed that the cross contacting resistances were about 50 μΩ. The results suggest that the time constants are around 0.1 s, which is shorter than the measured time constants of 5 to 100 s. This stems from the fact that the cross contact area, which is estimated about 10 μm in the elastic limit, is very small compared with the line contact area, which is the order of cm.In order to investigate the contact conditions in more detail, We fabricated a cable composed of 81 strands with 40% void fraction, and identified 3-dimensional locations of all strands in the cable. It is found that some loops have several line contacts with more than 10mm. This fact demonstrates that the loops with long time constants should be formed.

研究发现，电缆套管超导体中的不规则交流损耗无法从短导体样品测试结果中估计出来，电流回路必须在电缆中不规则地形成，随着时间常数的增加而衰减，从而增加交流损耗。我们提出了一种形成长环的机构，该机构由多个分段的子电缆组成，如果子电缆表面上的一根绞线与相邻子电缆表面上的另一绞线接触，则两根子电缆形成长环。绞线应在所有分级电缆节距的 LCM 距离处再次相遇，从而形成一对长环路。这些环路的时间常数基本上被描述为它们的电感与其接触电阻的比率。长LCM环路的时间常数τ=L/R，我们测量了LHe中两条线之间的交叉接触电阻，测试结果表明交叉接触电阻约为50μΩ。时间常数约为 0.1 s，比测量的 5 至 100 s 时间常数要短，这是因为在弹性极限下估计的交叉接触面积约为 10 μm，与实际情况相比非常小。线接触面积，单位为厘米。为了更详细地研究接触条件，我们制造了一条由 81 股空隙率 40% 组成的电缆，并确定了所有电缆的 3 维位置发现一些环路有多个超过10mm的线接触，这表明应该形成具有长时间常数的环路。

项目成果

期刊论文数量（25）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

対称性を持ったCIC導体構成の比較

对称 CIC 导体配置的比较

DOI：
发表时间：
2004
期刊：
第71回春季低温工学・超電導学会講演概要集 1
影响因子：
0
作者：
谷貝剛;濱島高太郎;他
通讯作者：
他

Contact condition between strands of a model CIC conductor

CIC 模型导体绞线之间的接触条件

DOI：
发表时间：
2004
期刊：
Abstracts of CSJ Conference Vol.70
影响因子：
0
作者：
Makoto Tsuda;谷貝剛;谷貝剛;Makoto Tsuda;T.Yagai;T.Yagai;M.Tsuda;谷貝剛;高畑一也;津田理;谷貝剛;谷貝剛;津田理;M.Tsuda
通讯作者：
M.Tsuda

CIC導体の素線軌跡調査と接触抵抗の検討

CIC导体绞线轨迹研究及接触电阻检验