Effects of Core Pin Hole Size and Placement on No-Load Losses in Power Transformers

This study examines the influence of core pinhole size and location on the performance of a 5 MVA transformer, focusing on core losses such as eddy current and hysteresis losses. Simulations were conducted using Finite Element Method (FEM) across scenarios with varying pinhole diameters (10, 15, and 20 mm) and positions (P0, P1, P2). Results indicate that smaller pinholes positioned near P0 which is closer to the corner of the core minimize core losses, while larger diameters and central placements increase losses due to magnetic flux disruption. These findings provide a basis for optimizing transformer core designs to enhance efficiency and balance structural requirements.