A Comparison of Different Wideband Models for a Single-Phase Distribution Transformer

This paper is focused on proposing and comparing the performance of different wideband models intended to represent a 10 kVA 7.967 kV/240-120 V single-phase transformer with center-tapped secondary used in rural distribution networks in Brazil. The terminal behavior of this transformer is characterized by three different modeling approaches: (i) reduced-order model, (ii) full-order admittance-based model, and (iii) hybrid model. In all cases the mathematical representation of the transformer is carried out using the vector fitting technique. The models arc validated in time domain by means of comparisons with experimental data. The results show that the proposed wideband models are able to accurately represent the behavior of the transformer in various operating conditions, although transferred voltages calculated in time domain with the full-order models are seen to present larger deviations from experimental data than those calculated with the reduced-order ones.