Suitable Structure of Triaxial HTS Cable with Low Thermal Conductive Layer for Increasing Power Transmission Cable Length

We have investigated the effectiveness of the insertion of a low thermal conductive layer (LTCL) in a triaxial high temperature superconducting (HTS) cable to realize a long-length triaxial HTS cable. This article analyzed the relationship among intrusion heat from outside of the cable, ac loss, temperature distribution, and the maximum temperature within a triaxial HTS cable with the LTCL to clarify the suitable insertion position and thickness of the LTCL for a long-length triaxial HTS cable. Analysis results showed that inserting the LTCL inside the HTS layers was effective for the long-length triaxial HTS cable. In addition, there was a tradeoff relationship between the effects of suppressing the thermal conduction from the outer refrigerant to the inner refrigerant and increasing the intrusion heat from outside of the cable by inserting the LTCL. The suitable thickness of the LTCL can be obtained by considering this tradeoff relationship.