Simplified saturation modelling in three-leg power transformer for the system stability analisys

The paper presents a simplified method for modelling non-linearity of the magnetic circuit of the power transformer. The saturation effect is implemented by describing the self and mutual inductances as a function of the magnetic flux. The most important element of this function is the saturation coefficient which is calculated based on transient state during the unloaded transformer switch on. The transformer model is described using the MAST hardware description language in Synopsys Saber simulator. Table Look-Up tool is used to define the saturation coefficient in function of the flux magnitude in per units. The simulation and measurements results were compared in order to verify modelling method.