Study on the Influence of Valve side Winding Defects on Electric Field Distribution of Converter Transformer

Abstract

Transformer is an important equipment in power system, and its operational reliability affects the safety of the whole system. As one of the main internal structures, it is of great engineering value to study the influence of winding defects on its insulation performance. In this paper, a simulation model is constructed by using finite element multiphysics simulation and the size parameters of the actual converter transformer, and four typical defects such as metal particles, corner rings, transformer oil and burrs are simulated respectively, and the electric field distribution and partial discharge process are restored under different voltages. Finally, the influence mechanism of defect-related parameters on transformer insulation performance is discussed and analyzed. The results show that the electric field distortion near the metal particles is serious, and the influence range is positively correlated with the particle size. The chamfer of the corner ring is prone to discharge along the surface, and the larger the radius of curvature of the corner ring, the more serious the distortion of the electric field. The higher the conductivity and average relative permittivity of transformer oil, the more likely partial discharge is to occur. Burr defects are easy to form a very uneven electric field, causing the occurrence of partial discharge.