A Numerical Model Comprising the Effect of Number of Turns on AC Losses in 2G HTS Coated Conductor at 77K using H-formulations

A 32 Tesla, all-superconducting user magnet, which consists of two high temperature superconductor YBCO inner coils producing a field of 17 T in an low temperature superconductor Nb3Sn and NbTi outer magnet producing a background field of 15 T, is being developed at the National High Magnetic Field Laboratory. The YBCO inner coils are pancake-wound with YBCO coated conductor tapes with an interleaved insulation of sol-gel coated stainless steel tapes. The coils are to be cooled directly in liquid helium bath. Heat losses in the windings, such as ac losses during ramping and heat loss in the internal joints, are supposed to be transferred to the coil external surfaces through heat conduction. Thus, thermal conductivity of the coil structure is critical for the internal cooling of the coil and also quench propagation if any. Thermal conductivity measurements were carried out in the radial direction on stacks of alternating YBCO tapes and stainless steel tapes. This paper presents the test results that showed a very low thermal conductivity in the radial direction. For comparison purposes, calculated thermal conductivities in the axial and azimuthal direction are also presented.

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Measurement of AC Losses in a Racetrack Superconducting Coil Made from YBCO Coated Conductor

Physics Procedia ◽

10.1016/j.phpro.2012.06.092 ◽

2012 ◽

Vol 36 ◽

pp. 980-984 ◽

Cited By ~ 2

Author(s):

Eugen Seiler ◽

Asger B. Abrahamsen ◽

Ján Kováč ◽

Mike Wichmann ◽

Chresten Træholt

Keyword(s):

Ac Losses ◽

Coated Conductor ◽

Ybco Coated Conductor ◽

Superconducting Coil

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Transport AC Losses of YBCO Coated Conductor Coils

MRS Proceedings ◽

10.1557/proc-1001-m11-04 ◽

2007 ◽

Vol 1001 ◽

Author(s):

Francesco Grilli ◽

Stephen P. Ashworth

Keyword(s):

Coated Conductors ◽

Ac Losses ◽

Coated Conductor ◽

Superconducting Tapes ◽

Practical Applications ◽

Superconducting Tape ◽

Ybco Coated Conductor ◽

The Magnetic Field ◽

Ybco Coated Conductors ◽

Transport Ac Losses

AbstractCertain practical applications of YBCO coated conductors (CC) involve superconducting tapes wound in coils. In such a configuration the superconducting tape is arranged as closely packed turns, leading to an increase of the magnetic field generated by the current in the tapes and, consequently, a significant increase in the AC losses, with respect to an ‘isolated’ tape. In order to predict and reduce the refrigeration requirements of applications, it is therefore very important to be able to quantify the magnitude of such AC losses, both experimentally and by means of numerical calculations.

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Coated conductor arrangement for reduced AC losses in a resistive-type superconducting fault current limiter

Superconductor Science and Technology ◽

10.1088/0953-2048/25/1/014005 ◽

2011 ◽

Vol 25 (1) ◽

pp. 014005 ◽

Cited By ~ 14

Author(s):

J Šouc ◽

F Gömöry ◽

M Vojenčiak

Keyword(s):

Ac Losses ◽

Coated Conductor ◽

Fault Current ◽

Fault Current Limiter ◽

Superconducting Fault Current Limiter ◽

Resistive Type ◽

Current Limiter

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Roebel assembled coated conductor cables (RACC): Ac-Losses and current carrying potential

Journal of Physics Conference Series ◽

10.1088/1742-6596/97/1/012147 ◽

2008 ◽

Vol 97 ◽

pp. 012147 ◽

Cited By ~ 10

Author(s):

A Frank ◽

R Heller ◽

W Goldacker ◽

A Kling ◽

C Schmidt

Keyword(s):

Ac Losses ◽

Coated Conductor

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AC Losses of YBCO Coated Conductor with Ferromagnetic Substrate in DC Field

Materials Science Forum ◽

10.4028/www.scientific.net/msf.745-746.191 ◽

2013 ◽

Vol 745-746 ◽

pp. 191-196

Author(s):

Guo Min Zhang ◽

Zhen Ling Xu ◽

Hui Yu ◽

Jin Cheng Li

Keyword(s):

Magnetic Fields ◽

Nickel Alloy ◽

Loss Factor ◽

Coated Conductors ◽

Ac Loss ◽

Ac Losses ◽

Coated Conductor ◽

Background Magnetic Field ◽

Repressive Effect ◽

Transport Loss

As YBCO coated conductors are usually prepared on nickel or nickel alloy substrates, additional ferromagnetic losses are generated in the substrates when the conductors are exposed to AC magnetic fields or carrying alternative currents in practical application. In this work, AC transport loss factors of YBCO tapes with Ni-W alloy substrates were studied in DC magnetic fields. The influence of ferromagnetic substrate on AC loss and the repressive effect of DC background magnetic field on ferromagnetic loss in the substrate were presented and analyzed. The results showed that the AC transport loss factor of YBCO tape with Ni-W substrate decreased gradually with the increasing background field, and the minimum value of AC loss factor appeared as the field reach to about 18 mT and 45 mT for parallel and perpendicular applied field respectively. Based on the analysis, the method to reduce AC transport current loss in coated conductor with nickel alloy substrate is proposed.

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