Published by Eric Bogatin on 04 Jul 2008
I wrote a column in 2001 on the first commercial use of high temperature superconductors (HTS) and have followed the technology since its creation in 1987. It was with great interest I read about a superconducting power transmission cable installed in Long Island, NY. This is a joint project between the Long Island Power Authority (LIPA) and the American Superconductor Corp (ASC). It was commissioned on April 22, 2008.
The cable is basically a pipe for liquid nitrogen with layers of high temperature superconductor (HTS) and insulation wrapped around the outside. As a power transmission system, the voltage rating is 138 kV, carrying 574 MegaWatts. This comes out to about 4kA. It’s only 2,000 feet long, but is a start.
While transmission losses from IR drop are typically 7-10% of the power transmitted, superconducting cables are lossless in principle. However, there is still the energy used in refrigerating the cable. There is a lot of room for improvement in insulation and heat pipe design, so in the long term, superconductor cabling for power transmission will be an important element to a large sacle, efficient power distribution network.