Magnetizing circuit model for EMTP including voltage dependence characteristic

This paper proposes a numerical magnetizing circuit model of an iron core including its voltage dependence. The proposed model logically consists of a saturatable R-L parallel circuit and a correction term that expresses the voltage dependence. The characteristic of the nonlinear inductor is determined by a magnetization curve. The correction term for the inductive current is defined as a function of an instantaneous voltage across the magnetizing circuit and a flux within the iron core. The term can be expressed by the TACS/MODELS feature of the EMTP. The proposed model simplifies an electrical part of a simulation circuit, because the final model can be represented by a nonlinear resistor and a TACS/MODELS controlled current source. The model expresses both the hysteresis characteristic and the voltage dependence of the magnetizing circuit. The accuracy of the proposed model is confirmed by measurements in steady and transient states of a transformer.