Thermal recovery of an inductive fault current limiter under different refrigeration conditions

We report new experimental results on the thermal behaviour of an inductive fault current limiter prototype based on a superconducting Bi-2223 tube. Our studies mainly focus on the recovery after a fault of relatively long duration (of the order of seconds). Tests have been made with the device submerged in a liquid nitrogen bath, and also in He gas and vacuum environments. We analyse the advantages of the increase of the limitation in He gas and vacuum environments as a consequence of the heating in the superconductor but also the problem of the very slow thermal recovery of the limiter, in the range of tens of minutes for a dissipated power around 30 W.