Test operation of 500 m /100 MW Ishikari high-temperature superconducting DC transmission line to demonstrate the required cost reduction and robustness

Abstract This paper presents the results of the Ishikari Line 1 restart test conducted in 2021 to collect basic data for cost reduction, improved efficiency, and confirm the integrity of the equipment. The Ishikari Superconducting DC transmission (SCDC) demonstration test facility was constructed in 2013 in Ishikari, Hokkaido. It comprises the world’s longest class of 500 m (Line 1) and 1000 m (Line 2) SCDC systems. In 2015, Line 1 successfully demonstrated the world’s first power transmission from a solar power plant to an Internet data center. The restart test was conducted approximately six years after shutdown, and a strong earthquake occurred during the shutdown period. The restart test operation confirmed the integrity and robustness of the facility, which had experienced a major earthquake. Cooling tests and electrical tests were conducted, and useful data were obtained, including efficient cooling operation and the integrity and shunt current of the superconducting cables. Based on these results, we aim to promote the social implementation of SCDC by compiling a database for the quantitative evaluation of reliability, safety, and cost.