Frequency response modeling of power transformer windings considering the attributes of ferromagnetic core

Abstract

The aim of the article is to present the method of modeling the inductances of the transformer windings, taking into account the complex magnetic permeability of the core material, and verification of obtained results. The research was carried out in two stages. In the first stage, the coil was wound on the distribution transformer core and the inductance of this coil was measured with precision LCR meter in the frequency range of 100Hz–1MHz. Subsequently, the computer model based on 3D Finite Elements Method (FEM) was prepared, while maintaining the original dimensions. The frequency response of the coil has been computed using the energy of the electromagnetic field delivered by FEM. The core model took into account its magnetic loss tangent, electric conductivity and magnetic permeability. Above parameters were parameterized in order to observe their effect on winding frequency response. Finally, the actual coil inductance measurements were compared to the results of computer analysis in order to confront the results of the winding frequency response with the response of computer model. Comparison shows deciding influence of core parameters on the frequency response below the frequency of 100kHz. As a result of the conducted research, a method of modeling the transformer core was proposed, which will be used for calculations the frequency response of the power transformer windings in a wide frequency range.