A Method for Calculation of the Inrush Current in Single Phase Transformer including the Residual Flux

A field-circuit method for simulation of transients in a single-phase, two-winding transformer has been given. The magnetic field excited by the winding currents has been analyzed, and integral parameters have been determined. Including the equivalent circuit parameters and the magnetic residual flux in the silicon steel core, the developed method has been implemented for the transitional states, especially for the transformer switching on. As numerical examples, the waves of the inrush current have been calculated in terms of the internal winding as well as external one supplying. Calculated waves of the inrush current were compared with those obtained experimentally from the tests of the single-phase transformer.