Analytical estimation of short circuit axial and radial forces on power transformers windings

In this study, an analytical method is proposed to calculate exerted axial and radial forces on the high and low voltage (LV) windings in core type power transformers. Hence, an analytical modelling approach is proposed to compute short circuit currents in the transient mode and steady state. The proposed model includes non-linear characteristics of the core materials, eddy currents effects, symmetrical and asymmetrical hysteresis loops of the used laminates. Then, exerted axial and radial forces on the high and LV windings are analytically computed in the transient mode and steady state. In order to certify obtained analytical results, the two-dimensional (2D) time stepping finite element method (TSFEM) is utilised to determine aforementioned forces. In this modelling approach, the geometrical, electrical and magnetic characteristics of the core type transformer under short circuit fault are taken into account. Furthermore, three-dimensional TSFEM is employed to verify the analytical and 2D TSFEMs results. © The Institution of Engineering and Technology 2014.