Electromagnetic force investigation on distribution transformer under unbalanced faults based on time stepping finite element methods

Najafi A., Iskender I.

INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS, vol.76, pp.147-155, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 76
  • Publication Date: 2016
  • Doi Number: 10.1016/j.ijepes.2015.09.020
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.147-155
  • Keywords: Electromagnetic force, Single phase to ground short circuit, Leakage flux, Inrush current, TSFEM
  • Eskisehir Osmangazi University Affiliated: No


The occurrence of short circuit faults is a major cause behind the windings deformation in the transformers. Mechanical force is proportional to the square of the current. Hence under short circuit condition, it will be very high. These stresses radially or axially affect the transformer windings. Therefore, in the transformer designing, evaluating the effects of short-circuit current and inrush current is very important. In this paper, 2-D and 3-D time stepping finite element methods (TSFEM) that improved in Ansoft-Maxwell, are utilized as Instruments to investigate the leakage flux and electromagnetic forces due to short circuit and inrush current on the windings of 1000 kV A, 10/0.4 kV three-phase, three leg, distribution transformer. Electromagnetic forces in the transformer windings are produced as a result of combination between the current density and the leakage flux density in the winding regions. The study demonstrates that, especially, under single phase-to-ground short circuit fault, leakage flux density on the windings of transformer remarkably increase. The interaction between this high leakage flux with current density, causes the significant increase in the electromagnetic forces in transformer windings. (C) 2015 Elsevier Ltd. All rights reserved.