Discharge Voltage Effects on High- \text Superconducting Tapes With Respect to Tensile Stress

Breakdown voltage can occur in a superconducting magnet system under high electric field conditions caused by inductive voltage, high-voltage operation, quench resistance, and keen edge of high-T C superconducting (HTS) tapes. Discharge voltage on a superconducting coil can degrade the critical current and the index number of HTS tapes. In this paper, HTS tape experiments are conducted to confirm the degradation characteristics of HTS tapes under dc breakdown voltage. In real systems, winding tension is applied in magnet systems. Therefore, tensile stresses were applied in the HTS tape when testing the degradation by breakdown voltage. The tension was controlled by using the bolt torque of a fabricated sample. In addition, degradation characteristics of BSCCO and YBCO tapes under dc breakdown voltage were compared. Our results revealed that HTS tape could affect breakdown voltage and tensile stress.