Harmonic Analysis of Inrush Current in Five-Limb Core Type Transformer by Using Extended Harmonic Domain

In this paper, Extended Harmonic Domain is used in order to simulate and exact harmonic analysis of five-limb core type transformers during the transients in addition to steady state. To this aim, low frequency model of transformer along with considering magnetic circuit, appropriate for studies in the range of power system frequency, are used. Then, modeling procedure of non-ideal core is mentioned and required mathematical equations for their appropriate implementation in extended harmonic domain will be expanded. Finally, analyzing of inrush current of a sample transformer by implementing the equations in Matlab software is simulated and in order to investigate the accuracy of the proposed method, results of the performed simulation are compared with those results derived from transient analysis in power systems software.