Frequency-Domain Diagnosis Methods for Quality Assessment of Nb3Sn Coil Insulation Systems and Impedance Measurement

In recent years, the superconducting Nb 3 Sn cable material became the privileged mature candidate for the high-field magnets in new projects like high-luminosity LHC (HL-LHC) accelerator at CERN, Geneva, Switzerland. The technology in 2017-2021 needs to be deployed through an unprecedented magnet s...

Full description

Saved in:
Bibliographic Details
Published in:IEEE transactions on applied superconductivity 2018-04, Vol.28 (3), p.1-5
Main Authors: Foussat, Arnaud, Grand-Clement, Ludovic, Smekens, David, Pincot, Francois Olivier, Bortot, Lorenzo, Savary, Frederic
Format: Article
Language:English
Subjects:
Capacitance
capacitance measurement
Dielectrics
frequency dielectric response
Insulation
Nb<named-content xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" content-type="math" xlink:type="simple"> <inline-formula> <tex-math notation="LaTeX"> _3</tex-math> </inline-formula> </named-content>Sn accelerator coils
Permittivity
Resins
Superconducting magnets
Temperature measurement
vacuum pressure impregnation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In recent years, the superconducting Nb 3 Sn cable material became the privileged mature candidate for the high-field magnets in new projects like high-luminosity LHC (HL-LHC) accelerator at CERN, Geneva, Switzerland. The technology in 2017-2021 needs to be deployed through an unprecedented magnet series production with dedicated online quality control. The key fabrication stage of the vacuum pressure impregnation (VPI) after the heat treatment reaction of Nb 3 Sn coils, as on the new 11-T dispersion region dipole, enhances both the structural integrity and the dielectric strength of the winding packs. The global vacuum impregnation pressure method exhibits various merits in insulation performance and high dielectric strength reliability, which is strongly dependent on the success of the resin filling cycle. This online capacitive measurement method enables one to derive comparative master trend curves of various impregnated coils and possibly optimize the curing cycle. Ultimately, a combination of the above methods with a dielectric frequency response can bring insights on the impregnation process, the impacts from the resin choice and insulation material quality on the degree of curing, and the coil assembly geometry. The frequency impedance measurement of the first short dipole models DP101-102 provides the distributed lumped circuit fitting electrical parameters for the transient characterization of produced magnets.
ISSN:1051-8223
1558-2515
DOI:10.1109/TASC.2017.2787748