Modeling the terminal impedance of power transformers for studies of fast front electromagnetic transients

In study of electromagnetic transients is necessary to use a model that satisfactorily represents the power transform. The comparison between distinct methodologies is a tool to prove the effectiveness of these models. Thus, this paper presents a comparative analysis, both in time and frequency domain, between two of them: the analysis of resonance and anti-resonance spots and the Vector Fitting methodology. Therefore, both techniques used the same field measurements of wideband terminal impedance took on the frequency band of 10Hz to 2MHz on the high voltage winding of a single-phase 200MVA, 525/√3 / 138/√3 / 13,8 kV power transform.