THERMAL CONDUCTIVITY OF HIGH TEMPERATURE SUPERCONDUCTOR COATED CONDUCTORS

High temperature superconductor coated conductors become more and more applicable, e.g. in transformers, power transmission lines or magnets. However, the question of electrical and thermal stability is still an important one. Thermal instabilities during operation can destroy the conductor. This can be prevented by adding a stabilizing metal layer improving the thermal conductivity of the conductor. Of course the thermal conductivity depends not only on the purity of the components but also on the manufacturing process of the composite tape, which alter the purity of the starting materials significantly. Consequently the thermal conductivity has to be measured. In this investigation superconducting tapes from different manufacturers are examined with the axial-heat-flow method. The measurement provides a quality rating of the stabilizing metal layer. The results allow for finite element analysis to predict the behaviour of the superconductor under thermal disturbances or at transient operating states.