BELMILOUD, FAYCAL ABDELAZZIZBENSMAIL, BOCHRAZELMAT, Samir2025-07-202025-07-202025http://dspace.univ-temouchent.edu.dz/handle/123456789/6716This dissertation focuses on the study of power transformers in terms of structure, function, insulation techniques, and internal electrical stresses. The Flux 2D simulation program was used to analyze the electric field inside the power transformer under six different conditions in terms of cable diameter and distance from the tube. The Weidmann method was applied to evaluate the dielectric stress in the insulating oil, taking into account the effects of geometric shape, mesh accuracy, and different modeling types (2D or axisymmetric). The results demonstrated the importance of diameter and distance in the distribution of the electric field. Safety margins were also calculated to confirm the validity of transformer designs even under overvoltage conditions.frThesis