New Material Requirements for Superconductor Grid Technology

AbstractSuperconductor ac and dc cables, fault current limiters and wind turbine generators offer solutions to key challenges in modernizing electric power infrastructure around the world. High critical current Jc is an essential requirement for the practical commercial operation of such systems. High temperature superconductor (HTS) wires have met the basic Jc requirements, and some initial systems have been successfully installed in the power grid. From an applications perspective, further progress in increasing the superconductor critical temperature Tc and critical current Jc could open up an even broader impact. However, thermal fluctuations and the resulting flux creep depress critical current, creating a trade-off between higher temperature and higher critical current. The origins of this trade-off are discussed. The YBCO material used in today's second generation HTS wires strikes a good compromise between these competing effects, and because of the flux creep problem, applications needs call for further research to be focused more on increasing Jc than on increasing Tc