Electromechanical stress in transformers caused by inrush and short circuit currents

Abstract

The purpose of this paper is to present two methodologies, one being analytic in nature and the other computational, both with the objective of producing a diagnostic of the electromagnetic forces, along with the electromechanical stresses which occur in transformers due to inrush and short circuit currents. To reach the desired outcome, a computational model was developed using the finite element method in its three-dimensional version. The computational package used was FLUX 3D. It should be noted that this platform permits the study of inter-relationships between the electrical, magnetic and mechanical magnitudes. The electromagnetic and electromechanical results obtained through these computational simulations will be analyzed side by side with those self-same magnitudes, which have had their origin drawn from analytical calculations or project values. It should also be noted that these studies can be used as a benchmark when reaching a management and/or technical decision as to the best time to preventatively repair and/or substitute a transformer. Lastly, it should be highlighted that the procedures investigated here in are based upon fundamentals which should be used to guide the project as well as the construction of the transformer, especially when concerning those points linked directly to the windings’ mechanical support structure.