Protection and quench detection of YBCO coils results with small test coil assemblies

Frederic Trillaud, Ing Chea Ang, Woo Seok Kim, Haigun G. Lee, Yukikazu Iwasa, John P. Voccio

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

This paper presents the results of an experimental and theoretical study of the stability and protection of small test coil assemblies wound with second-generation (2G) High-Temperature Superconducting (HTS) wires. The study, conducted as a part of the efforts to improve the design and applicability of YBCO wire technology to real-life power devices, such as magnets, focused on two specific issues: 1) internal voltage developed within the winding resulting from a spatially nonuniform normal zone in a coil that is effectively short-circuited across its terminals; and 2) detection of a localized "hot spot" with Acoustic Emission (AE) signals to complement the usual resistive voltage technique. Each test coil assembly, a stack of four single YBCO pancakes electrically connected in series and shunted by a "persistent- mode" switch, simulated a power-supply driven magnet a moment after a quench zone appeared within the winding. A heater was incorporated into each pancake coil to drive 25% (one pancake), 50%, 75%, or 100% (four pancakes) of the test coil assembly. Measured internal voltages arising from different quench sizes and distributions are compared with the results of the simulation. "Hot-spot" induced AE signals are also presented on a single coil to determine if AE signals may be useful to facilitate the early detection of a normal zone in HTS windings.

Original languageEnglish
Pages (from-to)2450-2453
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Volume17
Issue number2
DOIs
Publication statusPublished - 2007 Jun

Keywords

  • HTS magnet
  • Internal voltage
  • Quench detection
  • Quench protection
  • YBCO wires

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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