Finite-element modelling of YBCO fault current limiter with temperature dependentparameters

Abstract

In this paper, we present a numerical model which takes into account both the thermal andthe electromagnetic aspects of the over-critical current regime for high-temperaturesuperconducting (HTS) materials. The electromagnetic and thermal equations have beenimplemented in finite-element method (FEM) software in order to obtain a novelmodel for investigating the behaviour of the materials when the current exceedsIc and the superconductor material goes to the normal state. The thermaldependence of the electrical parameters, such as the critical current densityJc, has been introduced. This model has been used to analyse the behaviour of strip lines of aYBCO/Au fault current limiter (FCL) on a sapphire substrate. Simulations with currents exceedingIc have been performed, showing that the current limitation phase can be correctlyreproduced. Such a model can be used to study the influence of the geometry onthe performance of the FCL. It can replace experiments with currents exceedingIc which may damage or destroy HTS samples and devices.