Characterization and Tests of the HTS Tape and the Preliminary Pancake for the RSFCL of the SCARLET Project

Resistive Superconducting Fault Current Limiters (RSFCL) are a promising solution for the protection of medium and high voltage DC and AC power links. They are particularly needed if superconducting power cables are integrated into the DC grid to ease design requirements of the electrical system. In the framework of the European project SCARLET, this solution is studied for the protection strategy of a 1GW offshore wind power export system employing MVDC superconducting cable operating at 50 kV DC. This is achieved by selecting an HTS tape with suitable properties and designing the RSFCL with a proper number of parallel tapes wound in bifilar pancake coils. This work reports on the test characterization campaign carried out for an HTS tape candidate for the RSFCL for the SCARLET project. DC and AC tests are performed at both low current and overcurrent regimes, and the temperature-dependent resistance of the tape was also determined. A demonstrator pancake with 6 stainless-steel tapes and 4 HTS tapes was manufactured, intentionally limiting the HTS content as this preliminary stage of the project focused primarily on validating the feasibility of the manufacturing process. The results of the experimental campaign on this pancake are also presented, highlighting key design considerations for the subsequent fabrication of the final device.