Sumitomo Electric Industries Ltd, Fujikura Ltd and International Superconductivity Technology Center (ISTEC) developed large-current, low-loss 66kV superconducting power cables by using yttrium (Y)-based high-temperature superconducting wire materials.

Especially, the cable developed by Fujikura enables to reduce power transmission loss (in consideration of cooling efficiency) by 75% or more.

Sumitomo Electric
Sumitomo Electric established a 15m-long 66kV three-core superconducting cable system by using an Y-based superconducting wire material developed by the company (Three high-temperature superconducting cable cores are stored in one insulated pipe). It has the world's highest power transmission density and can be stored in a 150mm-diameter pipe line.

The company conducted a long-term electric current application test with an acceleration condition equivalent to 30 years of use and confirmed the stability of the system and that its alternating-current loss is 2W/m or less per phase when the current is 5kA.

Furthermore, Sumitomo Electric developed elemental technologies that help commercialize superconducting cable systems such as a current lead for the terminal connection part (for high-current connection) and a technology for interconnection.

Fujikura formed a 20m-long 66kV superconducting cable by using an Y-based superconducting wire material whose critical current is 500A/cm or higher. The company applied a current of 5kA and confirmed that its power loss is 1W/m or less per phase in a condition close to real environment.

When the alternating-current loss is 1W/m or less per phase with a current of 5kA, it is possible to reduce power transmission loss by 75% or more (in consideration of cooling efficiency), compared with existing superconducting power cables, Fujikura said.