Modeling of transformer nonlinearites taking hysteresis into account with consuming function and the harmonic balance method

This work presents a new approach for the steady state modeling of transformer core nonlinear magnetizing characteristic in the frequency domain taking hysteresis into account. The excitation characteristics of the transformer are presented by curve fitting techniques created by normalized piecewise excitation curve and consuming functions for the representation of the hysteresis curve. The harmonic balance method allows us to obtain the harmonic magnitude and phase angles of the excitation current. The method provides expressive formulas for practical engineering applications in transformer design and power system analysis based on minimal measured data requirements. The proposed model has been verified with experimentally obtained results for transformer magnetizing currents.