The short-circuit test results of 6.9kV/2.3kV 400kVA-class YBCO model transformer with fault current limiting function

Tomioka, Akihiro; Bohno, T.; Kakami, S.; Isozaki, Masaru; Watanabe, Kazuo; Toyama, K.; Sugiyama, S.; Konno, Masayuki; Gosho, Yoshihiro; Okamoto, Hiroshi; Hayashi, H.; Tsutsumi, T.; Iwakuma, Masataka; Saito, Takashi; Tanabe, K.; Shiohara, Y.

doi:10.1016/j.physc.2012.02.035

Cited by 7 publications

(4 citation statements)

References 5 publications

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“…On the other hand, the dielectric loss was as low as 0.6 W/m with the use of polypropylenelaminated paper, PPLP ® -C as the insulation material of the choice. [4,18] In this project, the several important technologies aiming at a 20 MVA were investigated and a 2MVA transformer using CCs were designed, fabricated, and verified as a demonstration device.…”

Section: Superconducting Transmission Cablementioning

confidence: 99%

Progress in R＆D of coated conductor in M-PACC project

Izumi¹,

Ibi²,

Nakaoka³

et al. 2014

Progress in Superconductivity and Cryogenics

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The five-year national project in Japan for R&D of coated conductors and applications, named as the Materials and Power Applications of Coated Conductors (M-PACC) project, was finished at the end of FY2013. The project consists of four sub-themes as cable, transformer, SMES and coated conductors. In the theme of coated conductors, the fabrication process had been developed to satisfy the requirements from the applications such as in-field I c performance, low AC loss in the long tapes etc. Through the project, the remarkable progress was achieved as follows; a high in-field minimum I c value over 54A/cm-width under 3T at 77K was realized in a 200m long EuBCO tape with artificial pinning centers of BaHfO 3 by the pulsed laser deposition (PLD) technique on the IBAD template. On the other hand, the AC loss reduction was confirmed in the tapes fabricated by both PLD and the metal organic deposition (MOD) techniques by scribing 100m tapes into 10-filamments. Additionally, the mechanism of the delamination phenomenon was systematically investigated and the strength was improved by eliminating the origins of the weak points in the films. Through the development, all targeted goals were accomplished and the several results were appreciated as a world champion data.

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Section: Superconducting Transmission Cablementioning

confidence: 99%

Progress in R＆D of coated conductor in M-PACC project

Izumi¹,

Ibi²,

Nakaoka³

et al. 2014

Progress in Superconductivity and Cryogenics

Self Cite

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“…A group at Nagoya University [5,6] has investigated the boundary between recovery and non-recovery after a fault as a function of the degree of fault current limitation and recovery load. A Fuji Electric/ Kyushu University group has demonstrated fault current limiting in a 0.25 s duration short circuit test of a 400 KVA transformer, with 10% fault impedance of the first peak rising to 33% at the end of the short [7,8]. Recovery with load current was not tested.…”

Section: Introductionmentioning

confidence: 99%

“…The LV former was designed to make allowance for the thermal expansion of the conductor when quenched [11]. Of the studies of fault current limiting transformers cited, only two [7,8] used subcooled liquid nitrogen, and the impact of the subcooled conditions on heat transfer and recovery was not investigated.…”

Section: Introductionmentioning

confidence: 99%

Fault current limiting HTS transformer with extended fault withstand time

Yazdani-Asrami

Staines

Sidorov

et al. 2019

Supercond. Sci. Technol.

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We describe the design, construction, and testing of a proof-of-principle 45 kVA, 450/450 V, single phase superconducting transformer with fault tolerant capability. This small-scale transformer demonstrates extended short circuit withstand time as a result of the high thermal mass of the windings as well as improved recovery under load due to the high heat transfer achieved in subcooled liquid nitrogen with wire coated to optimise boiling heat transfer. Primary and secondary windings consist of 38-turn single layer solenoids wound in helical trenches milled in glass-reinforced epoxy formers. The thermal mass of the 0.4 mm thick brass-laminated conductor provides for adiabatic fault withstand times over 1 s, allowing greater flexibility in the design of protection systems required to isolate faults. Enhanced heat transfer from the windings to the liquid nitrogen coolant allows the transformer to recover from the short circuit event, cooling from around 300 K to return to the superconducting state even while current close to the rated current continues to flow. Two factors contribute to the high heat transfer. Firstly the HTS transformer operates in subcooled liquid nitrogen, at 65 K–66 K at atmospheric pressure, significantly increasing the heat transfer compared to operation at saturated vapour pressure. Secondly, the HTS conductor is coated with solid polymer insulation with optimised thickness, which allows efficient cooling by nucleate boiling to take place over an extended range of conductor temperature.

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“…In addition, we succeeded in controlling the short circuit current into around three times as much as the rated current. The experimental results were reported in detail [5], [6]. However the theoretical analyses, in which flux-flow state was taken into account, have not been reported yet.…”

Section: Introductionmentioning

confidence: 99%

Development of REBCO Superconducting Transformers With a Current Limiting Function—Fabrication and Tests of 6.9 kV-400 kVA Transformers

Ohtsubo

Iwakuma

Sato

et al. 2015

IEEE Trans. Appl. Supercond.

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We are developing RE 1 Ba 2 Cu 3 O 7−δ (REBCO, RE: Rare Earth, Y, Gd, etc.) superconducting transformers with a current limiting function. The target is a 3φ-66 kV/6.9 kV-20 MVA one for a distribution power grid. We designed and built two pieces of 1φ-6.9 kV/2.3 kV-400 kVA superconducting transformers with YBCO superconducting tapes. One was wound with a YBCO tape with a copper stabilizing layer with a thickness of 300 μm. The other was 50 μm in thickness of copper. Making sudden short-circuit tests with a 200 MVA short circuit generator, we investigated the response of the YBCO superconducting windings against the fault excess current over the critical current. Repeated sudden short-circuit tests revealed the quite different response between them. In the case of fully stabilized with copper 300 μm thick, short circuit current flowed without decay. On the other hand, in the case of copper 50 μm thick, short circuit current was reduced around three times as much as the rated current. Using the numerical simulation program, which we made up on the basis of the results of sudden short-circuit tests of a 10 kVA test transformer, we quantitatively investigated the transition phenomenon of REBCO superconducting windings to normal state through flux-flow state due to fault excess current. As a result, theoretical simulation explained experiment quantitatively and clarified how to control the short circuit current.

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The short-circuit test results of 6.9kV/2.3kV 400kVA-class YBCO model transformer with fault current limiting function

Cited by 7 publications

References 5 publications

Progress in R＆D of coated conductor in M-PACC project

Progress in R＆D of coated conductor in M-PACC project

Fault current limiting HTS transformer with extended fault withstand time

Development of REBCO Superconducting Transformers With a Current Limiting Function—Fabrication and Tests of 6.9 kV-400 kVA Transformers

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