An aspect of transformer inrush current

Paper analyzes a sparking phenomena that were observed on power transformers during their first few energizing. Sparks occurred the flange between tank cover and side, in spite of fact jumper (copper link) was used. The phenomenon from different manufacturers, with various transformer ratings, three or five limb core. proposes simple electromagnetic model for analyzing phenomena. Three-phase is modeled finite element method (FEM) magnetic software. Simplified 3D used order to simulate well known core saturation inrush current event. Voltages side are calculated simulated conditions. same calculation possible currents flowing showing value several kA can be reached. In harmless mitigation measures proposed. However, by doing nothing, would disappear very soon.