Estimation of AC transport current loss generated in Bi2223 bulk for fault current limiter

Noda, Takeshi; Shimizu, Hirotaka; Yokomizu, Yasunobu; Matsumura, Toshiro; Murayama, Norimitsu

doi:10.1016/s0921-4534(02)01550-2

Cited by 2 publications

(1 citation statement)

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“…Bulk materials of high-T c superconductors (HTS) are promising for current leads of superconducting magnets [1] and fault-current limiters of electric power systems [2,3], because of negligibly small Joule heating under current transport and also because of very low thermal conductivity. However, the realization of such devices on an industrial scale requires further elucidation on the HTS bulks, to make clear the mechanism of loss generation under alternating-current (ac) transmission and also to enhance the current capacity approaching the demands for practical applications.…”

Section: Introductionmentioning

confidence: 99%

Alternating-current transport losses of melt-cast processed Bi-2212 bulk superconductor bars

Tsukamoto

Inada

Inagaki

et al. 2003

Supercond. Sci. Technol.

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Using a melt-casting method, we have fabricated two pieces of Bi-2212 bulk superconductor bar with square and rectangular cross-sections, and we have investigated the alternating-current (ac) transport self-field losses at 77 K. Despite the main contribution of hysteresis loss of the superconductor, there is some difference in the loss behaviour between these two samples. To elucidate the origin, we make numerical calculations on the ac transport self-field losses as a function of current amplitude I0 below the critical current Ic. At a fixed I0, the calculated values using the uniform Jc distribution and the actual cross-sectional geometry are much higher than the experimental data for the sample with a square cross-section 7.5 × 7.5 mm2, while there is good agreement between the calculation and the experiment for the sample with a rectangular cross-section 4.5 × 13.6 mm2. The discrepancy appearing in the sample with a square cross-section is ascribed to the actual Jc distribution, which is confirmed by critical current measurements when scraping off the sample. The local Jc value decreases significantly in going from the surface to the interior of the sample. This suppresses the extension of the flux-penetration region to the interior under ac current transmission and lowers the loss generation compared with the calculated results obtained by the uniform Jc distribution.

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Section: Introductionmentioning

confidence: 99%