Degradation Characteristics of REBCO Tapes According to Electrical Breakdown

Second-generation (2G) high-temperature superconducting (HTS) coated conductors are widely used to develop high-voltage superconducting apparatuses, such as HTS fault current limiters and HTS cables. In this study, experiments on electrical breakdown were performed in saturated liquid nitrogen (LN ₂ ) at a temperature of 77K to verify the relation between the applied voltage and electrically degraded characteristics of REBa ₂ Cu ₃ O _x (REBCO, RE: rear earth) tapes, such as the critical current (I _c ) and index n. We used three types of REBCO tapes to determine the effect of the stabilizer material on the electrical degradation characteristics of silver, copper, and brass. A sphere electrode system was used to conduct electrical breakdown experiments under AC and lightning impulse voltages. Accordingly, we determined that the electrical degradation characteristics of REBCO tapes depend on the stabilizer material according to the applied voltage.