TY - JOUR
T1 - Non-uniform ramping losses and thermal optimization with turn-to-turn resistivity grading in a (RE)Ba2Cu3Ox magnet consisting of multiple no-insulation pancake coils
AU - Wang, Yawei
AU - Zhang, Min
AU - Yuan, Weijia
AU - Hong, Zhiyong
AU - Jin, Zhijian
AU - Song, Honghai
N1 - This is the Author Accepted Manuscript of an article published in Wang, Y, Yuan, W & Zhang, M 2017, 'Non-uniform ramping losses and thermal optimization with turn-to-turn resistivity grading in a (RE)Ba2Cu3Ox magnet consisting of multiple no-insulation pancake coils' Journal of Applied Physics, vol 122, no. 5, 053902. The final published version is available via: https://doi.org/10.1063/1.4997738
PY - 2017/8/7
Y1 - 2017/8/7
N2 - This paper presents a study on the ramping losses of a high temperature superconductor (HTS) magnet consisting of multiple no-insulation (NI) (RE)Ba2Cu3Ox coils. The (RE)Ba2Cu3Ox (REBCO) conductor is the second generation HTS thin tape, where RE stands for rare-earth. During a ramping operation of the NI HTS magnet, losses are generated both across turn-to-turn resistances and inside superconducting layers. The former comes with radial current, which is called "turn-to-turn loss;" the latter one is induced by flux creep and jump, called "magnetization loss." The modeling and experimental studies on the ramping losses have been reported on single NI pancake coils in the previous part. In a HTS magnet consisting of multiple NI coils, the electromagnetic coupling between coils has a considerable influence on the distribution of ramping losses. Here, the experimentally validated model is used to investigate a HTS magnet consisting of 14 single pancake REBCO coils. The results show that both the turn-to-turn loss and the magnetization loss present a significant non-uniform distribution among the coils. The highest turn-to-turn loss occurs on the middle coils of the magnet, while the highest magnetization loss happens on the end coils. The non-uniform distribution of ramping losses can result in a considerable temperature difference among coils in the NI HTS magnet. It leads to an additional quench risk on the magnet and requires more attention in design. The distribution of the turn-to-to-turn loss can be optimized by adjusting the turn-to-turn resistivity. A much more uniform turn-to-turn loss distribution among coils is achieved by applying a graded turn-to-turn resistivity on the multiple coils.
AB - This paper presents a study on the ramping losses of a high temperature superconductor (HTS) magnet consisting of multiple no-insulation (NI) (RE)Ba2Cu3Ox coils. The (RE)Ba2Cu3Ox (REBCO) conductor is the second generation HTS thin tape, where RE stands for rare-earth. During a ramping operation of the NI HTS magnet, losses are generated both across turn-to-turn resistances and inside superconducting layers. The former comes with radial current, which is called "turn-to-turn loss;" the latter one is induced by flux creep and jump, called "magnetization loss." The modeling and experimental studies on the ramping losses have been reported on single NI pancake coils in the previous part. In a HTS magnet consisting of multiple NI coils, the electromagnetic coupling between coils has a considerable influence on the distribution of ramping losses. Here, the experimentally validated model is used to investigate a HTS magnet consisting of 14 single pancake REBCO coils. The results show that both the turn-to-turn loss and the magnetization loss present a significant non-uniform distribution among the coils. The highest turn-to-turn loss occurs on the middle coils of the magnet, while the highest magnetization loss happens on the end coils. The non-uniform distribution of ramping losses can result in a considerable temperature difference among coils in the NI HTS magnet. It leads to an additional quench risk on the magnet and requires more attention in design. The distribution of the turn-to-to-turn loss can be optimized by adjusting the turn-to-turn resistivity. A much more uniform turn-to-turn loss distribution among coils is achieved by applying a graded turn-to-turn resistivity on the multiple coils.
KW - insulation
KW - magnets
KW - colis
KW - electrical resistivity
KW - optimization
KW - high temperature superconductor
UR - http://www.scopus.com/inward/record.url?scp=85027180994&partnerID=8YFLogxK
UR - https://researchportal.bath.ac.uk/en/publications/non-uniform-ramping-losses-and-thermal-optimization-with-turn-to-
UR - https://aip.scitation.org/journal/jap
U2 - 10.1063/1.4997738
DO - 10.1063/1.4997738
M3 - Article
AN - SCOPUS:85027180994
VL - 122
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 5
M1 - 053902
ER -