TY - JOUR
T1 - Numerical analysis of current-limiting cooperation of a 20 mva superconducting transformer and cable
AU - Nakamura, Fumiya
AU - Iwakuma, Masataka
AU - Miura, Shun
AU - Yoshida, Kohichi
AU - Tomioka, Akira
AU - Konno, Msayuki
N1 - Funding Information:
Manuscript received October 30, 2018; accepted March 2, 2019. Date of publication April 4, 2019; date of current version June 28, 2019. This work was supported in part by the Advanced Low Carbon Technology Research and Development Program of the Ministry of Education, Culture, Sports, Science, and Technology, Japan, and in part by the Japan Society for the Promotion of Science KAKENHI under Grants JP18H03783 and JP17H06931. (Corresponding author: Shun Miura.) F. Nakamura, M. Iwakuma, S. Miura, and K. Yoshida are with the Institute of Superconductor Science and Systems, Kyushu University, Fukuoka 819-0395, Japan (e-mail:,miura@sc.kyushu-u.ac.jp).
Publisher Copyright:
© 2002-2011 IEEE.
PY - 2019/8
Y1 - 2019/8
N2 - In a previous study, we developed a 66/6.9 kV-2 MVA REBa2Cu3Oy (REBCO) superconducting transformer with a current-limiting function that was cooled with subcooled liquid nitrogen at 65 K. By considering the flux-flow state, it is possible to quantitatively explain the behavior of REBCO superconducting transformers and cables subjected to a sudden short circuit. Our goal was to demonstrate that limiting an excess fault current to triple the rated current after 0.2 s (while maintaining a superconducting state) was possible with the cooperation of superconducting transformers and cables. For that purpose, a numerical analysis was performed by coupling thermal equations and circuit equations. Consequently, the numerical analysis demonstrated that limiting the excess fault current to triple the rated current after 0.2 s can be achieved by adjusting the thickness of the stabilizing copper layer of REBCO superconducting tapes and the length and critical current, Ic, of the superconducting cable. Through these simulations, the balance of Ic and thickness of copper layers was shown to be important in limiting overcurrent and normal transition rates of the superconducting winding of the transformer and cable.
AB - In a previous study, we developed a 66/6.9 kV-2 MVA REBa2Cu3Oy (REBCO) superconducting transformer with a current-limiting function that was cooled with subcooled liquid nitrogen at 65 K. By considering the flux-flow state, it is possible to quantitatively explain the behavior of REBCO superconducting transformers and cables subjected to a sudden short circuit. Our goal was to demonstrate that limiting an excess fault current to triple the rated current after 0.2 s (while maintaining a superconducting state) was possible with the cooperation of superconducting transformers and cables. For that purpose, a numerical analysis was performed by coupling thermal equations and circuit equations. Consequently, the numerical analysis demonstrated that limiting the excess fault current to triple the rated current after 0.2 s can be achieved by adjusting the thickness of the stabilizing copper layer of REBCO superconducting tapes and the length and critical current, Ic, of the superconducting cable. Through these simulations, the balance of Ic and thickness of copper layers was shown to be important in limiting overcurrent and normal transition rates of the superconducting winding of the transformer and cable.
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U2 - 10.1109/TASC.2019.2909236
DO - 10.1109/TASC.2019.2909236
M3 - Article
AN - SCOPUS:85068178889
VL - 29
JO - IEEE Transactions on Applied Superconductivity
JF - IEEE Transactions on Applied Superconductivity
SN - 1051-8223
IS - 5
M1 - 8681412
ER -