Study of the Applicable Frequency Band of the YBCO Coil

Nowadays, copper Litz wire is widely used in the electrical applications. This wire is a particular type of multistrand wire, which is designed to reduce the skin effect and proximity effect losses in conductors. As the frequency dependence of losses in YBCO coils and Litz coils is different, how to determine the frequency band in which superconducting coils have an efficiency advantage over copper coils is a problem that needs to be solved. In response to the above concerns, a theory of the applicable frequency band of YBCO coils is proposed. Both experimental and numerical methods are used to study the characteristics of the applicable frequency band. Results show that the applicable frequency band of the YBCO coil decreases as the transport current increases, while its dependence on the radius of the coil is small. The obtained conclusions can be used as a reference when superconducting coils are used to replace copper coils.