Electrical and Mechanical Characteristics of HTS Twisted Stacked-Tape Cable Conductor

Abstract

Electrical and mechanical characteristics of a twisted stacked-tape cable (TSTC) made of REBCO tapes are presented for both power transmission and magnet applications. It was found that the twist-pitch length and bending diameter that results in 2% degradation in the critical current are approximately proportional to the tape width. The critical twist-pitch length and bending diameter are roughly 22 times and 150 times the tape width, respectively. The cable critical-current of a square cross-section TSTC conductor is proportional to the square of the tape width, while the critical engineering-current-density is independent of the width. Both the current and current density are inversely proportional to the tape thickness. Finally, a method to mitigate the thermal contraction of a conductor during cooldown for power transmission applications is also discussed. Using a helically twisted conductor, the thermal contraction can be minimized by designing a cable for which the twisted-cable-diameter is reduced during the cooldown process while maintaining the conductor overall length constant.