FEM analysis of current limiting devices using superconducting thin film and AC losses of YBCO coated conductor

A numerical analysis tool has been developed to study electromagnetic characteristics of high-temperature superconducting thin film used for a resistive-type fault current limiter (FCL) and coated conductor. It adopts the finite element method based on current vector potentials with thin-plate approximation. Transport current, temperature dependence and strong non-linearity of electromagnetic properties, and state transition of superconductor are taken into account by solving a three-dimensional coupled problem of electromagnetic field, an electric circuit and thermal field. Then using this numerical analysis tool the current imbalance and current limiting characteristics of a FCL device, the influence of inhomogeneity of superconducting properties on them, and AC losses in YBCO coated conductor are studied.