Resumo

GOMEZ-LUNA, Eduardo; APONTE, Guillermo  e  PLEITE, Jorge. Non-invasive monitoring of transformers using the frequency response from controlled transient signals. Ing. compet. [online]. 2013, vol.15, n.2, pp.23-33. ISSN 0123-3033.

This article presents a novel procedure for applying controlled transient signals analysis with the goal of obtaining the frequency response (FRA) with the transformer in service. For the procedure the method used is IFRA (Impulse Frequency Response Analysis) complemented with the Wavelet Transform. IFRA, has been implemented in previous works to transform transient signals from the time domain to the frequency domain by means of Fast Fourier Transform (FFT); however, Fourier is not the most suitable tool for this type of analysis since by definition, Fourier is useful for processing stationary signals. Taking that into consideration it was used Wavelet Transforms, given their variable time/frequency resolution, which improved the repeatability of the frequency response curves, as observed in experimental results. The analysis developed was applied in a single-phase distribution transformer of 7620/240 V, 3 kVA, to show the viability of the proposed method, for obtaining the frequency response curve, which could be used for power transformers in service

Palavras-chave : transformer; on-line FRA; transient signals; signal processing.

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