volume | PIER Journals

Abstract

Oil-immersed transformer bushings are critical power system components, whose internal defects can cause electric-field distortion and insulation breakdown. In this study, a three-dimensional finite element model of a transformer bushing is established via COMSOL Multiphysics using actual structural parameters. The baseline electric field and voltage distributions under defect-free conditions are analyzed, and systematic simulations and quantitative evaluations are conducted to explore electric-field distortion and corresponding insulation risks under four typical defects: capacitor core metal particle contamination, insulating oil gas bubbles, capacitor final screen grounding loss, and capacitor screen damage. The results demonstrate that all defects break the inherent electric-field uniformity and induce local field intensification. Metal particle contamination and capacitor screen damage pose the greatest risks of distortion and insulation breakdown, while grounding loss causes the most extensive overall electric-field disturbance. This study clarifies the defect-induced electric-field response mechanisms, providing theoretical support for fault early identification, risk warning, and optimized operation of oil-immersed transformer bushings.

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Dr. Gang Xu

Dr. Yangyang Li

Mr. Shuo Zhou

Dr. Liehong Huang

Dr. Yechuan Luo