Determining Accuracy of Temperature Limit Change in Power Transformer Core Using Temperature-Time Parameter Method

Abstract

The efficient transmission of electrical energy depends on amplifying voltage values with power transformers. To obtain higher efficiency from transformers, the core and winding type of transformer, the geometric structure of the core, and the shaping techniques in the windings are changed. This requires modeling transformer windings with equivalent circuits and calculating the inductance and electrical parameters appropriately. In this study, two-dimensional (2D) finite element solutions with energy perturbation and flux-coupling methods are used. The correctness of the inductance values of transformer windings was established, and the design was performed, by considering the inductance and electrical parameter values, which are comparable to the energy perturbation and flux connection. However, when two-dimensional calculated fields are used, the flux coupling method requires less computation and gives numerically more accurate results than the energy perturbation method. So, it is concluded that the flux-coupling approach should be chosen as the preferred method for calculating the inductance and electrical parameters of transformer windings. The numerical properties and equivalence of energy perturbation and flux-connection methods, the “apparent” inductance value of the primary and secondary field windings of power transformer operating under transient conditions, using the temperature-time parameter method, are calculated and its accuracy is demonstrated.