Width-bending characteristic of REBCO HTS tape and flat-tape Rutherford-type cabling

Abstract

The width-bending behaviors for a rare earth barium copper oxide (REBCO) high-temperature superconducting (HTS) tape have been investigated. It has been found experimentally that the width-bending strain of a Yttrium Barium Copper Oxide (YBCO) tape does not degrade the critical current as much as is expected from the axial strain. The critical current is not directly affected by the width-bending strain but by the axial strain, which the width-bending strain generates by the Poisson effect. Since Poisson’s ratio is about 0.3, the axial strain effective on the critical current is about 30% of the width-bending strain. Therefore, the width-bending strain of even 1.5% degrades the critical current by only 15% if the REBCO layer side is bent inward. However, the critical current degraded by more than 70% when the REBCO layer is outward. The width-bending effects on the critical current have been further examined, considering Poisson’s ratio changes and the neutral plane shift of the REBCO tape substrate. Those changes would occur when the material yields due to severe width-bending. Based on the width-bending of REBCO tapes, flat-tape Rutherford-type cabling is discussed. A REBCO Rutherford-type cable can provide various advantages, especially for narrow-tape cabling. The flat-tape Rutherford-type cable has better characteristics against an electromagnetic transverse Lorentz force. Furthermore, the tape length of the cable can be approximately the same as the cable length allowing for excellent tape usage. REBCO Rutherford-type cabling will be a promising high-current, high-field cabling method using thin substrate REBCO tapes. It will be useful for AC ramp-field and pulse-field applications with low AC losses and low shield currents. It notes that the filaments in the cable are symmetrically distributed in parallel. Therefore, each filament’s inductance is uniform, and a uniform current distribution among the filaments can be obtained.

Effect of off-axis bending on microstructural and transport properties of coated conductor tape

“…As shown from figure 12, the powerlaw exponent n followed the critical current I c behaviour of the tapes during the bending process in all cases. This behaviour of the superconducting properties of the bent tapes was also observed in other studies [15,32]. The critical current and power-law exponent of the tape tolerated bending in the IN configuration at much lower former diameters, i.e.…”

A 6-around-1 cable using high-temperature superconducting STAR ® wires for magnet applications

“…Rutherford cable, ubiquitous in superconducting accelerator magnets since the Tevatron, is a classic example of a transposed cable [18,20]. Rutherford-type cable using stacked rebco tapes have also been successfully demonstrated [21][22][23][24].…”

High temperature superconducting CORC cable with variable winding angles for low AC loss and high current carrying SMES system

“…Illustrated in figure 6(b), the outermost tapes bear the brunt of the highest induced current, given their direct exposure to the alternating magnetic field. Furthermore, a distinct induced current loop takes shape on the side facing the magnetic field [21]. AC losses of four different cable structures were simulated.…”

“…The HTS cable with high current capacity is desirable for the SMES system, as it allows for low inductance and high stored energy. Several composite HTS cables with high critical current (about several kA) have been proposed, including twisted stacked-tape cable (TSTC) [16], Roebel assembled coated conductor [17], conductor on round core (CORC) [18,19], SCSC CABLE from Kyoto University [20] and Rutherford cable [21]. The CORC cables manufactured by D C van der Laan et al had a critical current of 4404 A under 14 T [18].…”