Method to revise a simulation model of single-phase transformer using no-load current waveforms

Abstract

One of the areas of industrial digitalization is associated with the concept of digital twins, which allows simulating the operation of real devices in various modes. Currently, simulation packages such as MatLab Simulink, or physical field modeling systems, such as ANSYS Maxwell are applied. The problem is that, despite the declared accuracy, practically no model of a technical device can demonstrate a point-to-point correspondence of the simulation results and the experimental results, especially under transient conditions. It is caused by variations of material characteristics and difficulty to consider technological factors. The purpose of this article is to develop a method to revise the simulation model of a single-phase transformer. So, this model can provide 95 % accuracy of the coincidence of the instantaneous values of currents in the windings when simulating the operation of the transformer both in steady state and in transient modes. The authors have used the methods to model electrical circuits, simulation modeling using the MatLab Simulink SimPowerSystem package, experimental methods to record current and voltage oscillograms. The authors have studied the possibility of accurate modeling of transient and steady processes in a single-phase transformer, considering the nonlinearity of the magnetic properties of electrical steel and the mutual influence of magnetic fluxes of windings that close outside the magnetic core. To revise the model, a multichannel high-speed recorder developed by the authors has been used. A technique to revise a simulation model of a single-phase transformer using experimental oscillograms of voltage and no-load current has been developed. Application of the proposed method to revise the transformer magnetization curve using experimental oscillograms of a real transformer, as well as calculating the resistance of the parallel magnetization branch of the equivalent circuit of the transformer based on the oscillogram, makes it possible to obtain an almost point-to-point correspondence of the no-load current curve obtained when modeling with the experimental curve. The proposed technique to develop a simulation model gives more accurate results of modeling transient modes of transformers in comparison with analogues.