Electromagnetic and thermal performance study on the canted stack of REBCO tapes

Abstract Due to the critical current limitation of a single rare-earth barium copper oxide (REBCO) tape, stacking methods are generally employed to increase the current carrying capacity in practical high-temperature superconducting (HTS) applications. However, the overall critical current is strongly dependent on the self-magnetic field, which is influenced by the geometrical arrangement of conductors in the stack. Due to their brittle ceramic properties, REBCO tapes are conventionally bent along the thickness side of the tape. However, the difference in bending radii of the outer and inner tape surfaces in the stack may lead to fracture deformation, thereby limiting the stacking number of REBCO tapes. To balance the stacking number with the bending issue, a canted stack is proposed as a variant of the normal stack for REBCO tapes. As a potential HTS intermediate component, it is imperative to conduct a comprehensive study on the electromagnetic and thermal performance of the canted stack. The unique geometrical arrangement of the canted stack introduces new factors that affect the critical current and transport AC loss. This paper concludes with the special influencing factors of canted stacks, including canted angle, stacking number, tape width, and spatial structure. The metal interleaving method is introduced for spatial distribution changing and thermal stability. Furthermore, orthogonal analysis is performed to elucidate the comprehensive correlation among these multiple factors. This study provides insights into the overall critical current and transport AC loss for different combinations of canted stack and establishes a predicting function for critical current to support the structural design of canted stacks. Based on the specific case study, the improved capability of the canted stack is confirmed by both experiments and simulations.