World's First In-Grid High-Temperature Superconducting Power Cable System is

An in-grid superconducting power cable system at the Albany High-Temperature Superconducting (HTS) Cable Project, also known as the Albany Project, in Albany, New York, was recently energized. The system uses high-temperature superconducting cable manufactured by Sumitomo Electric Industries, Ltd. who claims it to be the first in the world to be used in an underground power grid. The superconducting cable system will undergo a demonstration test for the next six months.
Funded by the US Department of Energy (DOE) and the New York State Energy Research and Development Authority (NYSERDA), the Albany Project comprises 350 m of superconducting cable between National Grid's Riverside and Menands substations, installed and connected to the underground electricity grid. Three DOE-funded superconducting cable projects are currently underway. The Albany Project is the first among the three projects to complete the construction of a cable system and commence demonstration tests in a real power grid.

The Albany Project cable system comprises 350 m of 34.5 kV/800 A three-cores-in-one-cryostat type ("3-in-One") superconducting cable. The system also includes a measurement system and a cryogenic system. The superconducting cable is installed in an underground duct about 150 mm in diameter. The cable uses 70 km of Sumitomo Electric's bismuth superconducting wire (DI-BSCCO) manufactured using the company's proprietary "Controlled-over-Pressure (CT-OP)" sintering method.

Sumitomo Electric's "3-in-One" (three-cores-in-one-cryostat type) superconducting cable is designed to have three cable cores stored in one cryostat. This structure is said to have advantages over conventional superconducting cable design in that cable diameter can be made narrower and heat invasion less. The three cable cores are stranded by the "loose stranding" method to suppress thermal elongation/contraction that occurs when a superconducting cable is cooled and experiences a large temperature difference between room temperature and liquid nitrogen temperature (boiling temperature -196 deg C).