Thermal and Electrical Stabilities of Solid Nitrogen (SN2) Cooled YBCO Coated Conductors for HTS Magnet Applications

Abstract

Recently, a cooling system using a solid cryogen such as solid nitrogen (SN2), was introduced for high temperature superconducting (HTS) magnet applications. In order to apply the SN2 cooling system successfully to HTS applications, it is essential to obtain sufficient data regarding the characteristics of the SN2-cooled YBCO-coated conductor (CC), including the thermal and electrical properties. Therefore, this study examined the effect of SN2 on the thermal/electrical stability of YBCO CC tape. The SN2 was produced by conduction cooling using a GM-cryocooler and cooled to 58 K. The voltages and temperatures of the YBCO CC tapes were measured while applying an over-current. The results showed that the thermal and electrical stability of the YBCO CC tape were improved considerably in the SN2 cooling system compared to that in the conduction cooling system. Index Terms-Over-current, solid nitrogen (SN2), thermal /electrical stability, YBCO coated conductor (CC).

Thermal and Electrical Stabilities of YBCO Coated Conductor Tapes in a Solid Argon-Liquid Nitrogen Mixed Cooling System

“…where D th is the thermal diffusivity of SAr and is given by [14] D th = k ρc p (8) where k and ρ are SAr's thermal conductivity and density, respectively. The total volume of SAr and the diffusion time were determined here using (1)- (8).…”

“…The total volume of SAr and the diffusion time were determined here using (1)- (8). Tables 1 and 2 summarize the design parameters of the mixed cryogen vessel and the thermal properties of Ar, respectively, used in this study.…”

“…Lee ( ) Division of Materials Science and Engineering, Korea University, Seoul, Korea e-mail: haigunlee@korea.ac.kr Solid cryogens (SCs) have recently been introduced for cooling HTS power devices. They can enhance thermal stability and protection in cooling systems because they have excellent heat capacity [1][2][3][4][5][6][7][8][9]. SC systems provide large amounts of enthalpy with minimal weight, enabling portability in systems by increasing the recooling to recooling time period (RRTP) [9][10][11][12].…”

Effective potential for many-body interactions in some properties of the HFD-like solids

“…Recently, a cooling system using a solid nitrogen, was introduced for high temperature superconducting (HTS) magnet applications. In order to apply the solid nitrogen cooling system successfully to HTS applications, it is essential to obtain sufficient data regarding the characteristics and phase behavior of the solid nitrogen system [17]. The structural and phase behavior of solid oxygen have also been matters of continuous investigations and debates [18].…”

The Effects of External Pressure on the Thermal and Electrical Properties of Stacked GdBCO Coated Conductor Tapes

“…This higher stability is due to their large heat capacities, high operating temperatures, and lower dependence on an external magnetic field for a workable critical current value [1]- [8]. However, HTS magnets wound with 2G HTS tape are unlikely to be self-protecting due to their low normal zone propagation velocity (NZPV), which may lead to permanent damage of the magnets [8]- [14]. In addition, the 2G HTS CC may experience mechanical pressures induced by the magnetic field during the HTS magnet's operation.…”