Frequency Spectra for Admittances and Voltage Transfers Measured on a Three-Phased Power Transformer

摘要

Frequency spectra for admittance and voltage transfer were measured on a 25 MVA 150/11 kV transformer. Recorded input and output pulses were processed with the aid of a FFT algorithm to give admittances and voltage transfers. The results are reliable between 1 kHz and some hundreds of kHz additional measurements were carried out with a sweep generator and with stationary frequencies. The spectra show large scale phenomena with superimposed maxima and minima probably caused by part-winding resonances. A simple model, consisting of lumped capacitances and inductances is given to reproduce the large scale behavior.