Anthony JEANNETON defends his PhD on March 6th, 2023 at 09:30AM.
Place : Ecole Centrale de Lyon, bâtiment W1, Amphi 201, Ecully
Jury :
Rapporteurs
S AGNEL, Professeur à l’Institut d’Electronique du Sud (IES) - GEM - Université de Montpellier
N. BONIFACI , Chargée de Recherche CNRS au G2ELab, Grenoble
Examinateurs:
C. MOLLE-EPAIN, Docteure, GE Renewable Energy
C. PERRIER, Docteur, GE Grid Solutions, Villeurbanne
Encadrement
J. MARTINEZ, Professeur des Universités, laboratoire Laplace, Université Paul Sabatier (UPS)
A. BEROUAL, Professeur des Universités, laboratoire Ampère, Ecole Centrale de Lyon
Abstract :
Instruments Transformers (ITR) are high voltage electrical apparatus. They have a measuring and/or protecting function on the electrical network by decreasing current and/or voltage. ITR are mainly oil-filled. The data related to the aging of these devices are relatively low in comparison with other types of transformers such as power transformers (PTR). However, cases of failures are sometimes observed on this type of transformer (ITR), generally causing an explosion leading to the destruction of the latter and the damage of the surrounding equipment, thus presenting a potential danger for anyone nearby. In addition, the main insulating oil used in ITR are mineral oil. The mineral oils are petrol derivatives and thus not biodegradable, not renewable and easily flammable.
The aim of this study is the optimization of the oil-filled ITR’s insulation. The project is divided in two parts: alternative insulating materials and oil diagnosis. The alternative insulating materials part is focused on the study of other materials that could be biodegradable and/or having a better fire resistance compared to mineral oil. This thesis work has shown that: (1) biodegradable hydrocarbons have characteristics similar to mineral oils from the point of view of thermal aging while facilitating the step of impregnating the paper with the oil, (2) the ester liquids make it possible to increase the life of paper insulation, however, their greater viscosity lengthens the impregnation step of the paper and (3) silicone gels are also a possible alternative; the tests carried out indicate that the dielectric strength of this material complies with what is expected for the application with a thermal expansion slightly greater than that of mineral oils.
Finally, the optimization of diagnostics through oil aims to improve diagnostic techniques and ultimately make it possible to better anticipate cases of failure and avoid the explosion of equipment, and thus make existing equipment durable. The tests carried out with furfural and methanol seem to indicate a good correlation with the degradation of the paper. The contribution of infrared analysis to diagnosis is more limited. However, this technique has proved to be particularly interesting for the study of the phenomena of transesterification of paper in the presence of esters.
Keywords :
Instrument transformers, insulating liquids, insulating gels, thermal ageing, diagnosis
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