Production and Characterization of Strands for a 35 kA HTS DC Cable Demonstrator

Abstract

Over the past years, high temperature superconductors (HTS) Direct Current (DC) power distribution has received increased attention. One particular scenario is the application of HTS in energy-intensive industries to substitute conventional copper or aluminum bus bar systems. The use of HTS in these scenarios creates significant benefits regarding space, weight, and system losses. In industrial electrolysis, currents of up to several hundred kiloamperes are commonly encountered. One way toward a HTS cable with such high currents is to assemble multiple high current HTS strands into a cable. The HTS CroCo, developed at KIT, can serve as a high current strand for such cables. This paper reports on the progress in HTS CroCo manufacturing as well as the results of the CroCo characterization. With a new manufacturing machine, 8-m-long HTS CroCos within a round solder matrix were produced and cut into pieces, each 3.6 m in length. Twelve HTS CroCo pieces were characterized at 77 K, self-field. The tested HTS CroCos will be assembled to a HTS dc cable demonstrator that is designed to have a critical current of 35 kA at 77 K in self-field. To allow an individual measurement of the different HTS CroCos within the cable assembly, the strands will be connected in a first step individually to the feeding bus bar. The impact of the lead resistance and critical current distribution of the individual HTS CroCos on the current distribution within the assembled 35 kA cable demonstrator is discussed.