Published

2015-01-01

Experiences with non-intrusive monitoring of distribution transformers based on the on-line frequency response

Experiencias con monitoreo no-intrusivo en transformadores de distribución basados en la respuesta en frecuencia en línea

Keywords:

Transformers, on-line IFRA, Non-Intrusive Monitoring, Wavelet Transform, Energy (en)
Transformador, FRA On-Line, monitoreo no-intrusivo, Transformada wavelet, energía (es)

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Authors

  • Eduardo Gomez Luna

The following article presents the results obtained in experiences that use the Impulse Frequency Response Analysis (IFRA) method with a transformer in service. The IFRA method has been implemented in order to transform the transient signals to the frequency domain using Discrete Fourier Transform (DFT). However, it can be considered that the DFT is not the most suitable tool for this type of analysis, since, by definition, this tool is useful for processing stationary signals. Taking that into consideration, the analysis of transient signals could be hypothetically improved by using continuous wavelet transform (CWT), given their variable time/frequency resolution. The analysis of transient signals in Wavelet domain has improved the repeatability of the frequency response curves, as it has been ob-served in experimental results. The proposed on-line IFRA method, based on Wavelet transform, was validated under load and no-load conditions on a 150 kVA three-phase transformer 13200/225 Volts, in the Campus of the Universidad del Valle, Cali, Colombia.

El siguiente artículo presenta los resultados obtenidos durante experiencias donde se usa el método de análisis de la respuesta en frecuencia mediante impulso (IFRA) con un transformador en servicio. El método IFRA ha sido implementado para transformar la señal transitoria al dominio de la frecuencia usando la Transformada de Fourier (DFT). Sin embargo, puede considerarse que la DFT no es la herramienta más idónea para este tipo de análisis, ya que desde su definición esta herramienta es útil para el procesamiento de señales estacionarias y no para el análisis de la respuesta en frecuencia mediante impulso. Teniendo en cuenta esta consideración, el análisis de las señales puede ser hipotéticamente mejorado usando la Transformada Wavelet continua (CWT) dada su resolución variable en tiempo-frecuencia. El análisis de las señales transitorias en el dominio wavelet ha mejorado la repetitividad de las curvas de respuesta en frecuencia, como ha sido observado en los resultados experimentales. El método IFRA on-line propuesto, basado en la Transformada wavelet, fue validado bajo condiciones de carga y no carga en un transformador trifásico de distribución de 150 kVA, 13200/225 Volts, en el campus de la Universidad del Valle, Cali, Colombia.

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Copyright (c) 2015 Eduardo Gomez Luna

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