Electric Field Simulation Analysis of Typical Defects of Metal Particles in Main Insulation of Converter Transformer Based on Multi-physics Coupling

With the continuous expansion of China’s power grid and the ongoing improvement of transformer voltage levels, electrical insulation in converter transformers has become increasingly prominent as a critical component. The presence of typical external defects such as metal particles can easily lead to electric field distortion and partial discharge in micro-areas within converter transformers, resulting in significant insulation deterioration. Utilizing COMSOL finite element simulation software, we have developed a comprehensive multi-physics coupling simulation model to analyze the impact of metal particle defects on internal electric field distortion. Additionally, we investigate how different types, sizes, and positions of metal particles affect the distribution of main insulation electric fields and maximum field strength in converter transformers. This research aims to provide guidance for relevant factory tests.