Performance degradation of YBa2Cu3O7-δ tapes after suffering lightning impulse current

摘要

Over-current performance of YBa2Cu3O7-δ tapes under power frequency has been well-studied by previous researches. However, in power grid, superconducting apparatus will also experience lightning impulse current under special working conditions. In this paper, two kinds of lightning impulse current are applied to superconducting testing samples. Comparisons between superconducting characteristics before and after the testing are presented in this paper. Explanations of performance degradation are presented from both the perspectives of temperature and stress mathematic calculation. A maximum endurable value of lightning current which may not cause degradation is obtained from the testing results.