Spontaneous quenches of a high temperature superconducting pancake coil

Author

Lue, J.W. ; Lubell, M.S. ; Aized, D. ; Campbell, J.M. ; Schwall, R.E.

Author_Institution

Oak Ridge Nat. Lab., TN, USA

Volume

32

Issue

4

fYear

1996

fDate

7/1/1996 12:00:00 AM

Firstpage

2613

Lastpage

2616

Abstract

A double-pancake coil made of Bi-2223/Ag high temperature superconducting (HTS) tape was constructed with an embedded heater and graded conductors to study the stability and quench propagation in HTS coils. The experiments were performed with liquid nitrogen and gaseous helium cooling in temperatures ranging from 5 to 77 K. The coil was very stable, and no “normal” zone was sustained or propagated with local pulsed heating. However, spontaneous quenches of the coil were experienced. This was found to be the result of having the coil current higher than that of the lower I_c sections of the coil for a long time. This quench process took minutes to develop-much longer than would be expected in a low temperature superconducting coil. The quench behaved more like a spreading and continuous heating of an increasingly larger partially resistive section of the coil than like a sequential “normal” front propagation

Keywords

bismuth compounds; high-temperature superconductors; silver; superconducting coils; superconducting tapes; 5 to 77 K; Bi-2223/Ag high temperature superconducting tape; Bi₂Sr₂Ca₂Cu₃O-Ag; double-pancake coil; embedded heater; graded conductor; local pulsed heating; normal zone propagation; spontaneous quench; stability; Conductors; Cooling; Heating; Helium; High temperature superconductors; Nitrogen; Stability; Superconducting coils; Superconducting films; Temperature distribution;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.511409

Filename

511409