Superconducting fault current limiters can limit short-circuit currents in power transmission and distribution grids very quickly, effectively, automatically and, thus, with a high degree of intrinsic safety, making reliable grid operation possible even under difficult conditions. After a short cooling period, the grids can also return to normal operation without additional measures.
"With our innovative partner, Stadtwerke Augsburg, we have a power utility where we can demonstrate how this advanced technology can help master the challenges of the energy transition and grid upgrades successfully," said Dr. Tabea Arndt, head of Superconducting Components and Applications at Siemens Corporate Technology. "Powerful plants for renewable energies (EEG plants) must be connected to the grid via efficient fault current limiters to protect the electric components," said Jürgen Völkel, technical director of Stadtwerke Augsburg. Project head Thomas Janetschek added, "We already know where these could potentially be installed immediately."
Superconducting fault current limiters also have another advantage: they are "invisible" for the grid in normal operation since they have no electrical resistance at their low operating temperature of -196o Celsius. As a result, the limiters do not negatively impact the power grid's stability – unlike today's conventional short-circuit limiting reactors that have a continuously high resistance. On average, about 25 kilowatts of electricity is lost per conventional limiting reactor.
Superconducting fault current limiters also make it possible to link several different power sub-grids, thereby increasing operational security and grid stability. In addition, using the limiters to link several sub-grids or to connect decentralized energy feeders eliminates the added costs of replacing or upgrading electrical components that are frequently incurred when power grids are strengthened.