Superconducting Current Limiter
Friday, January 13 2012
The technology, co-developed by Germany's Karlsruhe Institute of Technology (KIT) and made by Nexans SuperConductors, enhances the intrinsic safety of the grid and may help reduce the investment costs of plants.
“For a long time, high-temperature superconductors were considered to be difficult to handle, too brittle, and too expensive for general industrial applications,” explains project manager Wilfried Goldacker of KIT. “The second generation of high-temperature superconductor wires based on YBCO ceramics is much more robust. Properties have been improved.” Superconducting current limiters work reversibly. In case of current peaks after short circuits in the grid, no components are destroyed. The limiter automatically returns to the normal state of operation after a few seconds only. Consequently, the power failure is much shorter than in case of conventional current limiters, such as household fuses, whose components are destroyed and have to be replaced with a high time and cost expenditure.
“Superconducting current limiters have a number of advantages for the stability of medium- and high-voltage grids,” says KIT's Mathias Noe. Reliable, compact current limiters enhance the operation stability of power grids and allow for a simplification of the grid structure. As they are protected against current peaks, decentralized energy generators - such as wind and solar systems - can be integrated much better in grids. Expensive components in the existing grid are protected efficiently, components in future grids can be designed for smaller peak currents, and transformers will no longer be necessary. Superconducting current limiters on the basis of YBCO can also be applied in high-voltage grids of more than 100 kilovolts for better protection against power failures in the future.