Study of the First Russian Triaxial HTS Cable Prototypes

Triaxial HTS power cables are the optimal solution for low and medium voltages. This design permits to save expensive HTS conductor and to increase the power density transmitted. They could be used at medium voltages ~10-20 kV for distribution grids. At relatively low voltages (<;1-10 kV), triaxial cables could be used for ship propulsion systems or in electrical aircraft, where higher voltages are prohibited due to operational conditions. Prototypes of HTS “triaxial” cables made of both Bi-2223 and ReBaCuO HTS wires have been developed and tested in the Russian Scientific R&D Cable Institute. The calculations to optimize the cables with three superconducting layers and outer copper shield have been performed. The optimal parameters have been determined. The Bi-based 10-m cable has been inserted in a full-size flexible cryostat with current leads developed and has been tested at dc and ac conditions. The 4-m ReBaCuO cable has been tested in a laboratory cryostat and tested at dc and ac conditions also. AC tests of both cables were performed at different frequencies from ~37 to ~400 Hz. The cables designs, test results, and their analysis are presented.