Thermal recovery of inductive superconducting fault current limiters with weak zones in the secondary

We study here the limitation performance and the thermal recovery of inductive superconducting fault current limiters (SFCL) with special emphasis on the case in which the superconducting element (i.e. the secondary) has weak zones. Our experimental results indicate that the conduction of heat between a hot weak zone and its cold surroundings plays an important role in its refrigeration. This suggests that it could be interesting to design superconducting elements based on an appropriate distribution of artificial weak zones. In this way, the heat would be removed more efficiently than in the case of homogeneous samples, where the heating would be uniform. By using a numerical simulation it is found that, with a proper distribution of artificially created weak zones, it could be feasible to simultaneously get a good current limitation (as big as with homogeneous secondaries) and a shorter recovery time. These results suggest an unexpected way to improve the performance of any SFCL.