Parameter Determination of a Condition for Simultaneous Quench in Series-Connected YBCO Coated Conductors

A simultaneous quench has been one of challenging issues in a development of a superconducting fault current limiter (SFCL) as long as series-connected superconducting materials are not identical each other. This paper deals with a parameter determination of a condition for simultaneous quench in series-connected YBCO coated conductors (CC), as a preliminary step to develop its faculties for high voltage CC applications. An electrical and thermal analysis based on the finite element method (FEM) showed that decisive parameters were critical current and n-value. For verifying the analysis, two sets of series-connected samples from a batch of AMSC 344S, which is clad on stainless steel, were short-circuit tested. One set has quite different critical current, whereas the other similar ones. The analysis estimated the quench initiation characteristics among the samples in both cases. After the verification, the condition for simultaneous quench, i.e. allowable deviation of critical current and n-value, has been obtained.