Demonstration and verification tests of a 500Â m HTS cable in the super-ACE project

A high-Tc superconducting cable (HTS cable) can transmit more power with lower loss than conventional cables. HTS cable is expected to be a compact and economical transmission line to meet the increasing electrical demands of cities. However, some technical problems must be solved to bring the HTS cable into practical use. Demonstration and verification tests of the world's longest (500 m) HTS cable have been carried out as part of the Super-ACE project. The 500 m cable was a single-core, cold-dielectric type with a small enough diameter to be installed inside a 150 mm cable duct. We have already successfully completed the production and installation required for the field tests at the Yokosuka laboratory of CRIEPI. The test layout included a 10 m high section, an underground section and an offset section for absorbing the thermal contraction, so as to simulate real transmission lines. Over the course of a year, CRIEPI and Furukawa Electric have conducted numerous experiments on the thermo-mechanical behavior and operating characteristics of the cooling system and the electrical and superconducting properties of the cable, both at its rated load and with a fluctuating load and an overload.