Determining the Positions and Dimensions of Horizontal Magnetic Shunts in Transformer Tank Walls Using Parametric Analyses Based on the Finite Element Method

Abstract

Magnetic shunts efficiently mitigate losses caused by leakage currents in the tank walls of power transformers. Transformer manufacturers frequently utilize vertical magnetic shunts positioned on the inside surfaces of the transformer tank walls. This study investigated the optimum use of horizontal shunts in a power transformer. A 50 MVA power transformer, manufactured on a commercial scale and featuring optimized vertical magnetic shunts integrated into the wall structure, was analyzed using the 3D finite element method for 100 ms at full load. Simulations for analyses were performed using a commercial ANSYS Electronics Desktop 2021 R1 FEM software program. The model's validity was demonstrated by verifying the analysis results with experimental tank loss values. Tank loss samples were obtained by analyzing the transformer tank for two milliseconds with vertical magnetic shunts only on the long front wall and the short side wall. Using these loss samples as a reference, parametric analyses were performed for two milliseconds with horizontal magnetic shunts only on the short side wall and only on the long front wall of the tank. A tank model with horizontal magnetic shunts of an appropriate location and size was obtained via the parametric analyses. This model was analyzed for 100 milliseconds at full load and compared with the experimental results of the transformer manufacturer's vertical magnetic shunt transformer. According to the results, a saving of 25.83% was achieved in the horizontal magnetic shunt volume compared with the vertical magnetic shunt volume. The maximum magnetic flux density was lower in the horizontal magnetic shunts, and the maximum current density was lower in the transformer tank with horizontal magnetic shunts.