Detailed High Frequency Models of Various Winding Types in Power Transformers

Kenneth Pedersen, Morten Erlandsson Lunow, Joachim Holbøll, Mogens Henriksen

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


Abstract--In this paper, techniques are described which demonstrate how a highly detailed internal transformer model can be obtained systematically with Matlab and how it can be prepared for subsequent transient analysis. The input of such a model will mainly be the description of the cross section of a single transformer leg, including all turns and windings. From the input data a three phase equivalent circuit is calculated and corresponding nodal impedance matrices are found for appropriate frequencies. Vector fitting is then applied which produces an excellent rational function approximation to the nodal impedance matrix in the valid frequency range. From the approximation an equivalent circuit can be extracted and implemented in circuit simulation software. A small but novel step makes it possible to compute not only the voltage distribution but also the internal currents from the extracted equivalent circuit. Finally a new circuit extraction technique is proposed for vector fitted impedance matrices for more efficient computation.
Original languageEnglish
Title of host publicationIPST 2005 Conference Papers
Publication date2005
Publication statusPublished - 2005
EventInternational Conference on Power Systems Transients (IPST). -
Duration: 1 Jan 2005 → …


ConferenceInternational Conference on Power Systems Transients (IPST).
Period01/01/2005 → …


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