Single‐phase transformer modeling for inrush currents simulation using differential evolution

SUMMARY Accurate modeling of transformer saturation characteristics is essential for analyzing inrush currents and ‎harmonic overvoltages. This paper outlines a straightforward method for correct estimation of the transformer's inrush current where the residual flux effect is considered. The Ι–Λ nonlinear characteristic of transformer core is estimated by the sum of ‎two exponential functions. The differential evolution optimization method is used to identify the parameters of ‎the iron core ‎model including the current flux nonlinear function and the core loss resistance. The ‎objective function to be minimized is the root mean square difference between the measured and calculated ‎inrush currents. The experimental iron characteristic is obtained from the secondary winding voltage ‎and primary winding current waveforms produced during transformer energization. The performance and accuracy of the proposed method have been verified by a close ‎agreement between simulation and measured inrush waveforms for a single‐phase transformer.