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High-temperature superconducting cable

superconducting cable

Today, superconductivity technology is receiving much attention. This technology that realizes zero electrical resistance is now reaching full flower. This article will invite you to the world of superconductivity.

 Sumitomo Electric Industry (SEI) started research and development of the superconductivity technology in 1960's. This technology, which came to worldwide attention after the discovery of high-temperature superconductive material in 1986, is having great technical potential in the fields of energy and electronics. Based on this belief, SEI has been promoting the research on practical application of superconductivity. The superconductivity technology is applicable to the essentials of our life, such as compact power cables for large-capacity power transmission, super-express linear motorcars, jumbo magnetic-field application equipment for manufacture of best-quality LSI materials, and high-frequency filters that improve cellular phones "sound quality.

History of Superconductivity Technology (Titles omitted from names)


Discovery of the superconductivity phenomenon by Kamerlingh Onnes (Leiden University, Netherlands).


Establishment of the *BCS Theory by Bardeen, Cooper, and Schrieffer.

*BCS Theory:
The theory of superconductivity that is based on a "pair" hypothesis, which asserts that electrons become the pairs (Cooper pairs) in the superconducting state. Zero electrical resistance and Meissner effect can be explained by this theory.


  • Discovery of high-temperature superconductive materials by Bedrnoz and Muller.
  • Verification and structural identification of high-temperature superconductive materials by Tanaka's group (University of Tokyo).


  • Discovery of Y-Ba-Cu-O superconductor by Chu (University of Huston) and others.Critical temperature was 90K, which exceeded the temperature of liquid nitrogen (77K).
  • " Superconductivity Fever (Superconductivity Boom) ".


  • Critical temperature 110K was achieved in Bi-Sr-Ca-Cu-O superconductor by Maeda (National Research Institute of Metals) and others.
  • Establishment of International Superconductivity Technology Center (ISTEC).
  • Establishment of Superconductivity Research Laboratory (SRL), an organization attached to ISTEC. (SEI is a special supporting member.)


Critical temperature 120K was achieved in Tl superconductor by Harman (University of Arkansas) and others.


Critical temperature 134K was achieved in Hg superconductor by Putilin (Moscow State University) and others.


Discovery of MgB2 superconductor by Akimitsu (Aoyama Gakuin University) and others. Critical temperature 40K was achieved, which was the highest in the intermetallic compounds.

The historical milestones of Sumitomo Electric’s BSCCO


DI-BSCCO Type HT-CA, ACT-CA were produced for Yokohama project Japan/TEPCO)


10kV HTS DC cable were shipped (Japan/Chubu Univ.)
DI-BSCCO Type HT-CA were supplied to Russian HTS cable project. (Russia/VNIIKP)


DI-BSCCO Type HT-CA on Sale


World’s first Superconductor EV (Electric Vehicle with HTS motor)
365kW motor (IHI et al.)
8T Magnet with 200mm RT bore


World's first underground in-grid HTS cable (SuperPower et al..)
100m Power Cable (Korea EPCO)
200A class DI-BSCCO


DI-BSCCO on Sale HTS Transformer for High Speed Train (Railway Technical Research Institute) HTS motor for Ship propulsion cooled by LN2 (IHI et al.)


1500m BSCCO wire by CT-OP on Sale




100m 3-in-One Power Cable (Tokyo EPCO)


Magnet for Silicon Pulling (Toshiba et al.)


1MVA Transformer (Kyushu EPCO et al.)
Magnet for Separation (NIMS)


30m 1-Phase Power Cable (Tokyo EPCO)


7T Magnet


Power Lead for SR ring


Discovery of BSCCO and R&D start in Sumitomo Electric

Critical Temperature

Critical Temperature

Critical Temperature
Red line: Superconductor
Yellow line: Oxide superconductor

 When a superconductor is cooled, its electrical resistance is lost at a certain temperature. This temperature is called critical temperature. Before the discovery of high-temperature superconductors, superconductors were cooled by liquid helium (boiling point is 4K).

 Oxide superconductors discovered in 1986 have the critical temperatures higher than those of conventional superconductors and becomes superconductive in liquid nitrogen (boiling point 77K). They are called the high-temperature superconductors. Nitrogen exists abundantly in the air and therefore is low cost. The discovery of the materials that become superconductive in liquid nitrogen raised the expectations that superconductivity technology would become practical.

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