Reel-to-Reel Fabrication of HTS CroCo Strands and Test of HTS CroCo Demonstrator Coils

Abstract

The High Temperature Superconductor (HTS) CrossConductor cable concept (HTS CroCo) was developed by the Karlsruhe Institute of Technology. Meanwhile the HTS CroCo manufacturing process is advanced to produce CroCo strands in a reel-to-reel process, with which a HTS CroCo was produced over 50 meters in length. In order to characterize the fabricated whole length of conductor, it is wound in a single layer solenoid geometry with a diameter of ∼97 cm that corresponds roughly to that from the production reel. The windings were arranged on the support structure of the coil in 13.75 turns first in a non-insulated manner. The assembly was cooled down to T = 77 K in a liquid nitrogen bath and then energized with current. After warming-up, the turns were insulated against one another by introducing a defined distance between the windings and the test procedure was repeated. In this contribution the results of current tests with the different demonstrator coils are presented. The current test program included charging and discharging, transient response and steady state operating conditions of both coil configurations. As the electrical behavior of a non-insulated HTS coil is different from an insulated one, further investigations are carried out by modelling of the electric performance of the coil.