Effect of Tapping Position on the Electromagnetic Forces of the Tap-Winding Transformer

The transformer is one of the major pieces of equipment in the electric power system, continued and stable operation of the transformers is very important for reliable power delivery. Electromagnetic forces and stresses have been a growing concern among electric power system operators and researchers. The higher electromagnetic forces and stresses not only damage the transformer but also lead to power system-related issues in the electric power system. In this study, the electromagnetic forces are investigated for the 1500-kVA tap winding transformer with three different primary winding voltage levels. Axial and radial electromagnetic forces are obtained by employing the transformer’s finite element models. Electromagnetic force characteristics of the five different tapping positions are investigated in this work, including (1) lower, (2) middle, (3) upper, (4) side, and (5) upper-lower tappings of the primary voltage winding using finite element analysis. The lowest electromagnetic forces are calculated in the side tapping and upper-lower tapping. The electromagnetic forces are higher in the upper tapping and lower tapping. The short-circuit experimental test is also performed to verify the accuracy of the numerical method.