SmartCoil - Concept of a Full-Scale Demonstrator of a Shielded Core Type Superconducting Fault Current Limiter

Within a German government funded project with the partners Siemens and KIT, we present the concept and first results for a full-scale inductive superconducting fault current limiter. It is based on the well-known shielded core concept but does not need the deployment of an iron core. Aim of the project is the construction and test of one phase with a nominal current I = 600 A and a voltage of U = 10 kV, i.e., a protected power of P = 10 MVA for the three-phase system. The shielding is provided by a stack of superconducting rings, i.e., YBCO-tapes soldered to closed rings, with a radius of R = 0.7 m. To obtain a sufficient coupling between the reactor (primary coil, warm) and the shielding stack, the minimization of the gap between both is crucial. The paper presents numerical work with respect to the overall geometry and the physical properties (limitation behavior, ac-losses) of the device. Also a suitable superconducting material had to be qualified. Finally, a test equipment for single components (rings) was built up and successful tests of first superconducting full size components are reported.