Infuence of Core Characteristics on Inductance Calculations for Modeling of Power Transformers

Calculations of effective parameters (inductance and resistance) of transformer windings, including core characteristics, are presented in this paper. Both anisotropic nature of the core and eddy currents in the electrical steel sheets are accounted for. A 3D model is developed and used to find out the inductance and resistance of transformer windings in the frequency range from 10 Hz to 10 MHz. It is shown that strongest variations of the magnetic field inside the core and of the effective parameters occur below 10 kHz, whereas the effect of the magnetic core is negligible above 1 MHz.