Performance tests of an HTS power transmission cable splice

Practical applications of high-temperature superconducting (HTS) transmission cables require that cable sections be periodically spliced together. An HTS transmission cable splice with a cold dielectric construction rated at 1250-A phase current and 7.5-kV phase-to-ground voltage has been fabricated by Southwire Company and tested at Oak Ridge National Laboratory. The splice joins the HTS phase and the neutral conductors as well as the Cryoflex™ dielectric tapes between the HTS conductors. Testing has demonstrated the nominal operating capability of the HTS cable splice and consisted of direct-current characterization and alternating-current high-voltage withstand testing at 18 kV. In addition, overcurrents up to 14 kA for 2 s were applied to the cable splice repeatedly without impacting the performance. The splice generates less than 1 W of heat into the cable at rated current. The results of these tests demonstrate the feasibility of splicing HTS power transmission cables.