Prediction of magnetizing current waveform in a single phase power transformer under DC bias

Conference: CEM 2006 - 6th International Conference on Computational Electromagnetics
04/04/2006 - 04/06/2006 at Aachen, Germany

Proceedings: CEM 2006

Pages: 2Language: englishTyp: PDF

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Bíró, Oszkár; Außerhofer, Stefan; Buchgraber, Gerhard; Preis, Kurt (IGTE, TU Graz, Austria)
Preis, Kurt; Seitlinger, Walter (VA TECH ELIN Transformatoren, Austria)

A method based on the finite element analysis of a transformer is presented capable of predicting the waveform of the magnetizing current with the voltage of the winding as well as the magnitude of the DC bias given. The relationship between the flux linkage of the winding and the value of the magnetizing current is determined assuming static conditions. With the aid of this flux-current curve, the dependence of the waveform and thus of the DC component of the magnetizing current upon the bias flux is established. Hence the flux bias yielding the given DC component is obtained by suitable iterative techniques arriving at the waveform of the magnetizing current having the prescribed DC value. Measurement of the current waveform at various voltages and DC bias has been carried out on a single phase transformer. The computed waveforms agree well with the measured ones.