Test Results of the 100 kWh SMES Model Coil. AC Loss Performance.

Hamajima, T.; Hanai, S.; Wachi, Y.; Kyoto, M.; Shimada, M.; Ono, M.; Shimada, Kazuhiko; Kushida, L.; Tezuka, M.; Martovetsky, N.; Zbasnik, J.; Moller, J.M.; Hirano, Naoki; Shinoda, Kimiyuki; Yamamoto, Masahiro; Takano, Ichiro; Himeno, Takashi; Satow, T.

doi:10.2221/jcsj.34.286

Cited by 11 publications

(13 citation statements)

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“…The measurements indicated that time constants for magnetic field variations differed at each position of the model coil, and the range of the time constants was 17-571 s, as listed in Table 3. Consequently, many current loops with various time constants would be induced in the model coil [7].…”

Section: Comparison Of Time Constants Between the Model Coil And A Shmentioning

confidence: 99%

“…In our investigative research of coils, five instances were found. The first instance is an SMES model coil for a small-scale 100 kWh SMES device, which was launched by the Ministry of International Trade and Industry of Japan [7,10,11]. The second and third are the CS insert and Nb 3 Al insert coils, respectively [12][13][14][15][16].…”

Section: Investigation Of Coils Having Long Time Constants and Consismentioning

confidence: 99%

“…The fifth is the inner shaping (IS) coil for the LHD poloidal coil [19,20]. Specifications of these coils are listed in Table 4 [7,[10][11][12][13][14][15][16][17][18][19][20].…”

Section: Investigation Of Coils Having Long Time Constants and Consismentioning

confidence: 99%

“…The longest measured time constants of these five instances and that of the JT-60SA CS model coil are listed in Table 5 [7,11,13,16,18,[21][22][23]. Each coil has an inherent time constant because the coils are composed of several different strands, conductors, and configurations, as listed in Tables 1, 2 and 4.…”

Section: Investigation Of Coils Having Long Time Constants and Consismentioning

confidence: 99%

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Magnetic field measurements of JT-60SA CS model coil

Obana

Takahata

Hamaguchi

et al. 2015

Fusion Engineering and Design

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Section: Comparison Of Time Constants Between the Model Coil And A Shmentioning

confidence: 99%

Section: Investigation Of Coils Having Long Time Constants and Consismentioning

confidence: 99%

“…The fifth is the inner shaping (IS) coil for the LHD poloidal coil [19,20]. Specifications of these coils are listed in Table 4 [7,[10][11][12][13][14][15][16][17][18][19][20].…”

Section: Investigation Of Coils Having Long Time Constants and Consismentioning

confidence: 99%

Section: Investigation Of Coils Having Long Time Constants and Consismentioning

confidence: 99%

See 2 more Smart Citations

Magnetic field measurements of JT-60SA CS model coil

Obana

Takahata

Hamaguchi

et al. 2015

Fusion Engineering and Design

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“…These resistances are not so small corresponding to time constants for the SMES and LHD-IV conductors of less than and 0.3 s, respectively. Because the cross over contact is a point less than 0.1 mm in length, this observation lead us to in- On the other hand, we have also measured the cross-over contact resistance of CuNi coated strands used for the improved SMES coil (Table II), where the irregular AC losses were not observed [2], [3]. The resistance was about 1 m that is about 20 times as large as those of strands in the SMES and LHD-IV conductor.…”

Section: Contacting Resistances Of the Loopsmentioning

confidence: 99%

Irregular AC losses with long time constants in large cable-in-conduit conductors

Hamajima

Kakusho

Hoashi

et al. 2003

IEEE Trans. Appl. Supercond.

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A large superconducting coil wound with Cable-in-Conduit (CIC) conductor causes both irregular AC losses that cannot be estimated from short conductor sample test results, and regular AC losses that are proportional to cable twisting pitch squared. We proposed a mechanism forming loops that generated the irregular losses. The CIC conductor is composed of several stages of sub-cables. If one strand on the surface of a sub-cable contacts another strand on the surface of the adjacent sub-cable, the two strands must encounter each other again at the LCM (Least Common Multiplier) distance of all staged cable pitches, and thereby a long loop is formed. We orderly labeled all strands in CIC conductors for the SMES and the LHD. It was found that strands in a triplet were widely displaced from their original positions on one cross section, but contacted each other tightly on the other cross section. This fact suggests that the loop with the large displaced strand links irregularly with external field so that the loops cause the irregular AC losses. Moreover, it indicates that a contacting length of the large displaced strands can be quite long, giving rise to a low contact resistance for the loop, and leading to the long time constants. It is believed that the widely displaced strand are inherent in a CIC conductor. It was demonstrated that the strand surface coated with CuNi was effective to suppress the irregular AC losses.

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Long‐time constants of irregular AC losses in a large superconducting coil

Hamajima

Yoshida

Shimamura

et al. 2003

Electrical Engineering Japan

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A large superconducting coil wound with a Cable‐in‐Conduit (CIC) conductor caused an additional AC loss, which cannot be estimated from the short conductor sample test results. It was confirmed that the additional AC loss was generated by long current loops in the CIC conductor. Magnetic field decays of the loops with various long‐time constants were observed through Hall probes. We propose a mechanism for the formation of the long loops. The CIC conductor is composed of several staged subcables. If one strand on the surface of a subcable contacts the other strand on the surface of the adjacent subcable, the two strands must encounter each other again at the LCM (Least Common Multiplier) distance of all staged cable pitches and thereby form a pair of long loops. We numerically traced each strand in the CIC according to a method in which the subcables at all substages rotate around the center of inertia. The calculated long‐time constants of the long loops were slightly shorter than the observed ones. We labeled all strands by order in a real CIC conductor, disassembling the cable carefully after peeling the conduit. It was found that the strands in a triplex were widely displaced from their original positions, so that their contacting lengths became longer than the calculated ones. This fact makes the time constant of the loop longer and hence can explain the observed long‐time constants. The proposed mechanism is effective for estimating the long loops causing additional AC losses in the coil. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(1): 50–57, 2003; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.10064

show abstract

Test Results of the 100 kWh SMES Model Coil. AC Loss Performance.

Cited by 11 publications

References 0 publications

Magnetic field measurements of JT-60SA CS model coil

Magnetic field measurements of JT-60SA CS model coil

Irregular AC losses with long time constants in large cable-in-conduit conductors

Long‐time constants of irregular AC losses in a large superconducting coil

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