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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. [ABSTRACT FROM PUBLISHER]

In this contribution, we develop a refined numerical model of pancake coils assembled from a coated conductor Roebel cable, which includes the angular dependence of the critical current density Jc on the magnetic field and the actual (three-dimensional) shape of the current lead used to inject the current. Previous works of ours indicate that this latter has an important influence on the measured value of the AC losses. For the simulation of the superconductor, we used two alternative models based on different descriptions of the superconductor’s properties and implemented in different mathematical schemes. For the simulation of the current lead we use a full three-dimensional finite-element model. The results of the simulation are compared with measurements and the main issues related to the modeling and the measurement of Roebel coils are discussed in detail. [ABSTRACT FROM PUBLISHER]

A homogenization method to model a stack of second generation High Temperature Superconducting tapes under AC applied transport current or magnetic field has been obtained. The idea is to find an anisotropic bulk equivalent for the stack such that the geometrical layout of the internal alternating structures of insulating, metallic, superconducting, and substrate layers is 'washed' out while keeping the overall electromagnetic behavior of the original stack. We disregard assumptions upon the shape of the critical region and use a power law E-J relationship allowing for overcritical current densities to be considered. The method presented here allows for a computational speedup factor of up to 2 orders of magnitude when compared to full 2-D simulations taking into account the actual dimensions of the stacks without compromising accuracy. [ABSTRACT FROM AUTHOR]