Topics The World’s Largest 5 kArms-class Yttriumbased High-temperature Superconducting (HTS) Yttrium-based coated conductors are expected to be adapted to the various superconducting applications. They have a high current density and show high performance in liquid nitrogen, which is much cheaper than liquid helium used for the conventional superconductors. In 1991, Fujikura succeeded in developing the key original technology to fabricate yttrium-based coated conductors, which is ionbeam-assisted deposition (IBAD) method. An 816.4 m long wire with end-to-end critical current (Ic) of 572 A/cm-width, corresponding to the world record Ic ¥ L value of 466,981 Am/cm, was achieved by Fujikura. In the NEDO project (Apr. 2012 ~ Feb.2013), yttrium-based IBAD wires with high Ic=600A class/cm-width (@77K,s.f.) was applied to an HTS power cable for the first time in order to verify the merit of large current capacity and extremely low loss. We designed and fabricated the power cable with 4-mm wide tapes that have higher Ic of 240 A at 77K,s.f. as shown in Fig.1 and Table. The layout of current loading test line is shown in Fig.2. We built the 66kV 5kArms HTS cable system at Sakura Plant of Fujikura Ltd. as shown in Fig3. The current loading test of the cable proved that the measured AC loss of the cable in Fig.4 was sufficiently less than the target value of 2W/m/ph@5kArms at 77K. These results indicate that we can extremely reduce AC loss at the world’s largest current 5kArms by applying high Ic yttrium-based IBAD tapes. Acknowledgment This work was supported by the New Energy and Industrial Technology Development Organization (NEDO). Power Cable High Ic yttrium-based IBAD tape Cryostat Core protection HTS shield HTS conductor Former Electric insulation Copper shield Fig. 1. Appearance of yttrium-based HTS cable. Table. Specifications of the cable. Fujikura Technical Review, 2014 Items Specifications Former Stranded copper wires, 20 mm f HTS conductor (Ic=14 kA) All 4 mm-wide tapes, 4 layers Ic=240 A/4 mm-wide (77 K,s.f.) Electric insulation Craft papers HTS shield (Ic=12.7 kA) All 4 mm-wide tapes, 2 layers Ic=240 A/4 mm-wide (77 K,s.f.) Copper shield Copper tapes, 44 mm f Core protection Non-woven fabric tapes, 45 mm f Cryostat/Outer sheath Stainless steel double corrugated pipes with PE jacket, 114 mm f 43 Current lead cable Terminal vessel HTS cable 20 m Current transformer Cooling system Topics Power supply Power amplifier The World’s Largest Fig. 2. Layout of current loading test line of the HTS cable. 5 kArms-class Yttriumbased High-temperature Superconducting (HTS) Power Cable Terminal vessel Cooling system Cooling system HTS cable Terminal vessel Current transformer Fig. 3. The whole view of verification system. Target AC loss : <2 W/m @5kArms AC loss (W/m) 2 Measured AC loss 1.5 Conductor loss + Shield loss 1 77 K 67 K 0.5 0 0 1000 2000 3000 4000 5000 6000 Current (Arms) Fig. 4. Measurement result of AC loss of HTS cable. 44