Engineering of second generation HTS coated conductor architecture to enhance the normal zone propagation velocity in various operating conditions

Abstract

The effects of operating conditions, critical current and stabilizer geometry on the normal zone propagation velocity (NZPV) of second generation (2G) high-temperature superconductor (HTS) coated conductors (CCs) are investigated using finite element simulations. The NZPV of tapes with a low interfacial resistance between the HTS and stabilizer layers are first compared with tapes with a current flow diverter (CFD) architecture. Our results indicates that the CFD concept increases the NZPV for the whole range of operating temperatures investigated (10–77 K). In particular, for an operating temperature of 77 K and an operating current of 0.9Ic, our numerical results indicate that the NZPV of a 2G HTS CC with a CFD architecture and a 2 μm thick stabilizer layer could reach a value of 50 m s−1. Furthermore, numerical simulations realized on the effect of the stabilizer geometry on the NZPV of 2G HTS CCs revealed that putting most of the stabilizer on the substrate side can enhance the NZPV by a factor of 7 or more, even for tape with thick stabilizer (20 μm or more). This is particularly promising for improving quench detection in applications requiring a thick stabilizer such as superconducting coils.