Influence of winding capacitances to ground modelling on the calculation of transferred voltages in power transformer

Abstract

During voltage transients, the windings of a transformer are coupled by electric and magnetic fields. To calculate the transients inside the transformer, a network model is typically used. The accuracy of obtained calculation results depends mainly on this model in which the windings are lumped into R, L and C circuit components. The windings are usually represented by discs, or groups of discs, with the corresponding resistances, inductances (self and mutual) and capacitances (series and to the ground) [1]. In case of impulse voltage, wave’s steep front and consequently high frequency oscillations are the main reason why capacitances modelling is of major importance for the calculation of voltage distribution in winding and between windings.