Accurate Predication of Dynamic Loss in Superconductors
High Tc superconducting coated conductors, such as YBCO and GdBCO wires, can be applied to a wide range of novel power applications, such as superconducting machines, fault current limiters, and power cables. However, one key difficulty in designing the HTS devices is that the internal HTS coated conductors present a complicated heat load while carrying transport currents in external magnetic fields, which is inevitable. This loss makes the maintenance of the HTS devices at low operational temperature difficult and expensive. Cooling power, which is up to a hundred times as high as the loss, is required to remove the heat. Therefore it is vital to be able accurately estimate how much loss is dissipated, in order to understand it and reduce it. The loss dissipates in the form of magnetisation loss and dynamic loss (transportation loss), with the latter one only exists under certain conditions which depend heavily on transport current and external magnetic field.
This talk presents a numerical method for accurate prediction of the dynamic loss in HTS coated conductors. We then compare our calculations with experimental values of the dynamic loss of a SuperPower YBCO wire at different transport currents under a selection of AC magnetic fields. Through this study, we are aiming at clear explanation of how dynamic loss occurs, and how it changes within a complex environment when both transport current and external magnetic field varies.