Contribution à l’étude des charges d’espace dans les composites en HT

Abstract

When a dielectric is subjected to electrical, thermal or mechanical constraints, we can observe in certain regions of the material an excess of electrical charges called space charges, which is a major factor in the dielectric behavior of insulators and the service life of electrical systems. This thesis focuses on the development of new insulating materials for high voltage and the study of the effect of space charge by analyzing the dielectric characteristics of composite materials through modeling and experimental validation. Experimental validation is conducted on samples of materials developed in the laboratory. The study deals with three main parts: The first part concerns the study the dielectric properties of barium titanate as a function of the addition of MgO at different levels. The second part is dedicated to the measurement of space loads by the pulsed electro-acoustic method (PEA). The last part describes the numerical model used for space charge simulation in LDPE / Al2O3 composites. The use of numerical methods are valuable tools for determining the dielectric characteristics of composite materials. They allow an economy of means and time in the design and the prediction of the characteristics of the heterostructures