Finite element analyses of short circuit forces in power transformers with asymmetric conditions

Short circuit forces may be destructive in a power transformer. Therefore, accurate evaluation of such forces is essential during the design and manufacturing phase. Otherwise, overestimated values may result in oversized, and in general, non-optimal design. The analytical methods are usually fast and easy to apply. However, these methods fail to include essential factors such as non-linearity of the core, complexity of the geometry and boundaries, and also non-uniform distribution of current in large cross-sectioned conductors. On the other hand, numerical methods, in particular finite element method are capable to include the aforementioned complexities. Using this method, different components of forces on each part of the windings can be calculated. In this work, a 2D model is developed and the short circuit forces on different parts of a 10MVA power transformer are calculated; the influence of some factors, including the asymmetrical excitation, and relative displacement of the windings are studied. The commercial software, VECTORFIELDcopy is used as the finite element software.