Transport AC Loss Characteristic of $\text{YB}{\mathrm{a}}_{2}\mathrm{C}{\mathrm{u}}_{3}{\mathrm{O}}_{{\rm{7 - \delta \ }}}$ Coils With and Without Magnetic Substrate Up To 10 kHz

Transport ac loss is a crucial reference for evaluating the performance of high-temperature superconducting materials. Although the transport ac loss of $\text{YB}{\mathrm{a}}_{2}\mathrm{C}{\mathrm{u}}_{3}{\mathrm{O}}_{{\rm{7 - \delta \ }}}( {\text{YBCO}} )$ single tapes has been well studied, the transport ac loss characteristic of YBCO coils with different substrates in the kilohertz frequency band is still unclear, which is important for a wide range of applications, such as wireless power supply systems and high-frequency superconducting transformers. In response to the aforementioned concerns, both numerical and experimental methods are used to study the frequency dependence of transport ac loss in YBCO coils with magnetic and nonmagnetic substrate over a frequency range, from 55 Hz to 10 kHz. The mechanism of the loss of each turn and the distribution of the transport current of each turn are clarified. It is found that there is a frequency dependence of the distribution of both the loss and the transport current in each layer of each turn, and this distribution is highly dependent on the spatial location and the magnetic properties of the substrate.