Modelling of Saturation in a Single Phase Transformer by Using Instantaneous Saturation Curve

Accurately modeling the saturation present in transformer iron cores, so that it fully reflects all of the effects saturation has on the current waveforms, presents a challenging task. Over the years, several different approaches for modeling transformer saturation have been developed and used. One of the more complex methods includes computing a so-called instantaneous saturation curve, which describes the instantaneous magnetizing flux value against the value of the magnetizing current. This paper offers an experimental verification of the instantaneous curve method for the case of a single-phase transformer using the Humusoft MF 634 acquisition card. The recorded values of no-load voltage and current are used to obtain instantaneous saturation curve which is used in dynamic simulation model. By comparing the waveforms and harmonic content between simulated and recorded currents in the open-circuit experiment for different values of input voltages, we have shown the applicability of the method and demonstrated that we can realistically model the behavior of the transformer, both in linear and saturated modes.