Investigation of the Key Factors Affecting the Permanent Damage of the REBCO Coated Conductor in Overcurrent Condition

The effects of inhomogeneous critical current (I_c) and n-value on the degradation or permanent damage of REBCO coated conductors (CCs) were investigated through repetitive quench tests and overcurrent tests. In the repetitive quench tests, the I_c values of the REBCO CC samples at the sections with the high n-values were degraded easily due to the existence of thermal stress. Furthermore, the overcurrent test results showed that the REBCO CC samples burned out only at the section with the highest n-value, regardless of their I_c values and the manufacturing process. Therefore, this study confirmed that the n-value of an REBCO CC is one of the essential factors affecting the degradation or permanent damage of CCs in the overcurrent condition.