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Caractérisation et modélisation du comportement diélectrique d'un matériau composite soumis à un vieillissement hydrothermique

Abstract : The purpose of this work is to study water diffusion (hydrothermal ageing ) into epoxy composite materials used as groundwall insulation in statorbars of turbine generator and its effect on the dielectric and electric properties of the material.
Breakdown voltage is found to be strongly decreased with water uptake. Dielectric spectroscopy at low frequency (below 10-1Hz) and at low field shows a large sensitivity of the dielectric properties (Ε' et tanΔ) to water uptake, while the same mesurements performed at high field do not show any variation with respect to the former. With the help of DC current measurements, the material is appeared to be constituted of water clusters wherein the charge transport between them is favored by temperature and field direction.
A model have been develloped to calculate the potential distribution and electric field in aged material in statorbar structure. The calculation of electric field clarified the drop of reliability when the material is subjected to hydrothermal ageing. This result also suggests a new diagnostic method of insulation.
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https://tel.archives-ouvertes.fr/tel-00011163
Contributor : Thinh Pham Hong <>
Submitted on : Wednesday, December 7, 2005 - 3:48:47 PM
Last modification on : Wednesday, November 4, 2020 - 2:43:55 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 4:25:01 PM

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  • HAL Id : tel-00011163, version 1

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Thinh Pham Hong. Caractérisation et modélisation du comportement diélectrique d'un matériau composite soumis à un vieillissement hydrothermique. Autre. Université Joseph-Fourier - Grenoble I, 2005. Français. ⟨tel-00011163⟩

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