Detailed three-phase circuit model for power transformers over wide frequency range based on design parameters

This paper presents a detailed three-phase transformer model, the elements of which are expressed analytically according to the physical layout and the design construction parameters of the power transformer. These expressions have been calculated theoretically and verified through finite elements simulations.The proposed model allows to obtain the internal voltage distribution through the three-phase transformer in any type of operating condition, particularly when it is simulated in an electromagnetic time domain transient simulation tool, providing an external and internal characterization of the transformer in a frequency band that can appear in a power system (up to 1 MHz).The obtained results have been compared with both lightning and low frequency tests measurements, showing a good agreement.

► A detailed three-phase power transformer model based on construction parameters is proposed.
► Proposed model allows obtaining the internal voltage distribution on power transformers in any type of operation condition.
► Improvement of power transformer modeling in comparison with conventional high frequency models.
► All parameters model can be calculated from design constructive parameters and are verified through finite elements simulations.