Feasible voltage-tap based quench detection in a Ag/Bi-2212 coil enabled by fast 3D normal zone propagation

Abstract

Feasible voltage-tap based quench detection in a Ag/Bi-2212 coil enabled by fast 3D normal zone propagation To cite this article: Tengming Shen et al 2016 Supercond. Sci. Technol. 29 08LT01 View the article online for updates and enhancements. Related content High-field quench behavior and dependence of hot spot temperature on quench detection voltage threshold in a Bi2Sr2CaCu2Ox coil Tengming Shen, Liyang Ye, Daniele Turrioni et al. -Strain control of composite superconductors to prevent degradation of superconducting magnets due to a quench. I. Ag/Bi2Sr2CaCu2Ox multifilament round wires Liyang Ye, Pei Li, Jan Jaroszynski et al. -Quench degradation limit of multifilamentary Ag/Bi2Sr2CaCu2Ox round wires Liyang Ye, Pei Li, Tengming Shen et al. -Recent citations Very-high thermal and electrical conductivity in overpressure-processed Bi 2 Sr 2 CaCu 2 O 8+x wires M Bonura et al -Strain control of composite superconductors to prevent degradation of superconducting magnets due to a quench: I. Ag/Bi 2 Sr 2 CaCu 2 O x multifilament round wires Liyang Ye et al

Stable, predictable and training-free operation of superconducting Bi-2212 Rutherford cable racetrack coils at the wire current density of 1000 A/mm2

“…An important advantage of Bi-2212 coils revealed by this work is that their quench is global and essentially predictable. Several meters of the Bi-2212 cable in the high field region developed stable voltages (tens to hundreds of µV) well before thermal runaway and they then enter thermal runaway nearly simultaneously, as observed in RC1, RC2, and RC3 33 and a single-strand (140 m long), epoxy impregnated Bi-2212 solenoid tested in a background field of 14 T 35 . The predictable quench behavior of these Bi-2212 coils is due to the uniqueness of Bi-2212 as a round, isotropic multifilament HTS wire, now available in km-lengths with excellent current sharing in classic Bi-2212 Rutherford cables (evidenced by a n-value of greater than 20 (Figure 6)).…”

Quench Detection and Protection for High-Temperature Superconductor Accelerator Magnets

“…It is also in contrast to that of LTS conductors, where the voltage rise is typically associated with a formation of the normal zone that either shrinks or expands rapidly, without exhibiting an intermediary stable configuration for the hot spot. While voltage developed in the "slow" regime can be very low, the advantage of its persistence may be taken, and multiple voltage measurements can be averaged together to improve sensitivity of the quench detection [26]. In order to estimate the voltage developing across the hot spot, normal zone propagation velocity (NZPV) should be considered.…”

Very-high thermal and electrical conductivity in overpressure-processed Bi2Sr2CaCu2O8+x wires

“…The increase of mass density, electrical connectivity and critical current density (J C ) induced by overpressure processing has made Bi 2 Sr 2 CaCu 2 O x 8+ (Bi-2212) a credible candidate for solenoids and accelerator magnets able to generate magnetic fields unattainable with low-temperature superconductors [1,2]. Whether Bi-2212 can be preferred to other high-temperature superconductors (HTS) for high-field applications depends also on the mechanical, thermal and electrical stability of the conductor [3][4][5]. The residual-resistivity ratio (RRR) of the normal-metal matrix is a key parameter for both the thermal and the electrical properties.…”