Effects of transformer models on the voltage variation of an unbalanced distribution system in the presence of harmonic distortion

Distribution transformer models at high frequency become a subject of great concern in harmonic propagation studies in distribution and transmission systems owing to their impact on harmonic distortion. A laboratory based transformer model was recently investigated using a computer controlled harmonic generator. This paper presents the effects of this transformer model on the voltage variation as functions of the frequency of an unbalanced distribution system in the presence of harmonic distortion. The results are compared with the other available transformer models. A 44 kV distribution system is used as a test case and the voltage variation at each bus in the system is obtained using the developed computer program and the McGraw-Edison harmonic analysis program (V-HARM).