Analysis of high-frequency oscillations in voltage transformers

High‐frequency oscillations in voltage transformers are analyzed by the FFT method, using an equivalent lumped circuit. Such an analysis has been regarded as difficult because the transformers used in high‐voltage distribution systems have a large number of turns. The constants of the equivalent circuit are evaluated on a turn‐to‐turn basis. The frequency domain analysis is followed by time domain analysis using the FFT technique. Both characteristics are verified by an experiment on a 6.6‐kV voltage transformer. The nature of the high‐frequency oscillation is shown for a simpler model. It is found that the interlayer voltage becomes highest at the entrance to the incoming surge. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(1): 8–15, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20643