Measurements of ramp-rate limitation of cable-in-conduit conductors

Takayasu, M.; Ferri, M.A.; Gung, C.; Painter, T.A.; Steeves, M.M.; Minervini, J.V.

doi:10.1109/77.233742

Cited by 29 publications

(5 citation statements)

References 1 publication

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“…If a large project like ITER-FEAT will not be realized, there is the risk that all the specific know how developed in the industry will be dispersed or cancelled in a relatively short time. Even though experimental coils, some of significant size, have been manufactured and operated with variable success especially in pulsed mode [29,30], little experience exists about these cable in conduits. This technology is slowly merging mainly in relation to magnets for fusion application.…”

Section: Discussionmentioning

confidence: 99%

Development of high-current high-field conductors in Europe for fusion application

Duchateau

Spadoni

Salpietro³

et al. 2002

Supercond. Sci. Technol.

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In the framework of the preparation for the realization of the international thermonuclear experimental reactor (ITER), the construction and test of relevant models of seven different parts of the reactor was decided. Two of them are related to the superconducting coils: the toroidal field model coil (TFMC) and the central solenoid model coil (CSMC). For these superconducting coils, due to the expected high values of the current (≥60 kA) and voltage (≥5 kV with respect to the ground) the adopted technology was that of cable in conduit conductor (CICC). Until recently, little experience of this technology existed. Therefore, an extensive research and development programme has been carried out, in the last 10 years, by the ITER partners and particularly in Europe, to design, industrialize and test these large conductors and their joints. The EURATOM associations CEA and ENEA played a leading part in this phase. The CICC concept is described and the results of the developments are presented. About 7 km of conductors were manufactured in the industry and for that more than 10 tonnes of Nb3Sn strands were produced in Europe. In this large programme, Europe is particularly in charge of the TFMC, which will be tested this summer at Forschung Zentrum Karlsruhe (Germany). In the framework of this programme, three full size conductors and joint samples were tested at the European Sultan test facility (Centre de Recherches de Physique des Plasmas, Villigen, Switzerland), to validate the technological choices and check that the ITER specifications were met. The results of these tests are presented in detail. Starting from the strand critical properties, the conductors made of about 1000 strands did reach their expected performance. The joints of these large conductors are very special and delicate components. Their behaviour was quite successful and the joint resistance of these samples (of the order of 1 nΩ) was well within the specifications.

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Section: Discussionmentioning

confidence: 99%

Development of high-current high-field conductors in Europe for fusion application

Duchateau

Spadoni

Salpietro³

et al. 2002

Supercond. Sci. Technol.

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“…The experiments were performed using the same 27 (3x3~3) strand CICC used in previous RRL experiments [2]. At the terminations, however, a single strand was separated from the other 26 and was connected to an independent power supply [3].…”

Section: Experimental Set-upmentioning

confidence: 99%

“…Evidence considered in [2]-- [5] shows that non-uniformity of current distribution in strands may be responsible for the degradation of AC operation current in multistrand cables. A non-uniform current distribution implies some strands are carrying higher than average current and thus are more susceptible to quench.…”

Section: Introductionmentioning

confidence: 99%

“…The ramp rate limitation (FUU) phenomenon [l], [2] and AC current degradation in multistrand cables [4] are of general importance for all applications of superconductivity connected with non-steady state operational conditions. Evidence considered in [2]-- [5] shows that non-uniformity of current distribution in strands may be responsible for the degradation of AC operation current in multistrand cables.…”

Section: Introductionmentioning

confidence: 99%

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New method of current distribution studies for ramp rate stability of multistrand superconducting cables

Vysotsky

Takayasu

Ferri

et al. 1995

IEEE Trans. Appl. Supercond.

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The Ramp Rate Limitation phenomena were studied using local field sensors to observe the intrinsic processes within the cable. Sensitive miniature Hall sensors and small pick-up coils placed around Cable-in-Conduit Conductor were used to measure local magnetic fields and field derivatives associated with currents in the cable. Using this method both fast jumps and slow changes in local magnetic fields at different conditions were observed. Fast jumps occured during ramping background magnetic field and may indicate a fast current redistribution processes. Slow changing of local fields may be associated with current loops closed through the current lead joints. Such current loops may also indicate the non-uniformity of current distribution in the cable strands. The new method is a promising tool for future investigations of stability of multistrand cables.

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“…While defects pose particularly severe operational risks in LTS cables, the operating conditions and design of REBCO tapes and cables offer the opportunity for significantly improved defect tolerance: the structural and stabilizer materials in a cable have a higher heat capacity and thermal conductivity at the typical REBCO operating temperature (20 K) than at the typical LTS operating temperature (4 K) [10], giving REBCO cables and magnets greater thermal stability against defect-induced heating; thermal stability is further enhanced by the larger operating temperature margin afforded by REBCO's high critical temperature; electrical and thermal redistribution around defects is more effective in REBCO than in LTS [11][12][13][14][15][16][17], largely because of the flat geometry of REBCO, which provides greater contact surface area between the tapes than between cylindrical LTS strands; further opportunities for greater operational and mechanical robustness and quench stability are provided by various REBCO cable architectures [18][19][20], particularly those that employ soldering to improve the connection between tapes, such as the VIPER cable [21] and NINT coil [22,23].…”

Section: Introductionmentioning

confidence: 99%

A platform to study defect-induced behavior in high-temperature superconductor cables

Ibekwe,

Riva,

Whyte

et al. 2024

Supercond. Sci. Technol.

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High-temperature superconductor (HTS) cables and magnets are enabling a range of high-current and high-field applications, including compact fusion devices aiming to achieve net energy. Defects in HTS pose manufacturing, cost, and operational challenges. A rigorous understanding and predictive capability for defect-induced behavior at relevant scale has not been established. To address this shortcoming, we have developed a cable-level defect characterization experimental platform coupled to high-fidelity computational modeling. The cable (I c ∽ 438 A at 77.4 K, self-field) comprises a non-twisted 70 cm-long copper former containing a soldered stack of five REBCO tapes (each with I c = 115.7 A/4 mm-w at 77.4 K, self-field), which can contain a variety of induced defects. Spatially-resolved electric fields are measured with a high-density voltage tap array and absolute current distribution with six custom-wound embedded Rogowski coils. 3D circuit modeling uses nodal analysis and self-consistently accounts for the magnetic field dependence of critical current. The model successfully predicts the experimentally measured spatial and operating current dependencies of electric field and current distribution with no defects, one defect, and two defects, validating the defect characterization platform as a tool for improving the design, cost, fabrication, and operation of REBCO cables.

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Measurements of ramp-rate limitation of cable-in-conduit conductors

Cited by 29 publications

References 1 publication

Development of high-current high-field conductors in Europe for fusion application

Development of high-current high-field conductors in Europe for fusion application

New method of current distribution studies for ramp rate stability of multistrand superconducting cables

A platform to study defect-induced behavior in high-temperature superconductor cables

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