Wideband Modeling of Power Transformers Using Commercial sFRA Equipment

Andrzej Holdyk, B. Gustavsen, Ivan Arana Aristi, Joachim Holbøll

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This paper presents a new procedure to characterize an admittance matrix over a wide frequency band, for the purpose of black-box modeling of power transformers. Unlike previous approaches, our setup is based on a commercial sweep frequency response analysis (sFRA) measurement instrument which is light-weight and considerably less expensive than dedicated high precision laboratory equipment. The use of 50 Ω termination resistors allows measuring the terminal admittance matrix without a need for correcting for the measurement cables. The measured admittance matrix is next subjected to rational modeling using Vector Fitting and passivity enforcement. When applied to a 300 kVA distribution transformer, the resulting model accurately reproduces measured time domain waveforms.
Original languageEnglish
JournalI E E E Transactions on Power Delivery
Issue number3
Pages (from-to)1446-1453
Publication statusPublished - 2014


  • sFRA
  • High frequency transformer models
  • Vector Fitting
  • EMT program
  • Frequency domain measurements
  • Time domain measurements
  • Model creation and validation

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