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1

The study of phased-ultrasonic receiving-planar array transducer for PD location in power transformer

Jisheng L., Yongfen L., Junhao L., Yanming L.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 3

324-328

EN

Partial discharge (PD) is the main cause of electric equipment degradation. PD location can provide the scientific direction and analysis for equipment condition monitoring. The phased-ultrasonic receiving-planar array transducer for PO location in transformer is studied in this peper. The operation environment and material properties of transducer are analyzed. The center frequency of transducer is 150 kHz and its bandwidth is 100 kHz. The piezoelectric source and oil interstitial defect are used to detect the transducer's performance in lab. Experimental results show the transducer has perfect ultrasonic receiving characteristics. The successful developments of this sensor provide a good foundation for PD location in transformer using phased-ultrasonic receiving-planar array transducer.

PL

Wyładowania niezupełne są częstą przyczyną uszkodzeń urządzeń elektrycznych. W artykule przedstawiono ultradźwiękowy przetwomik o czestotliwości 150 kHz zaprojektowany do lokalizacji wyładowań nie zupełnych. Preprowadzne eksperymenty dowiodły przydatności takiego przetwornika.

2

Chaotic characteristics of time series of partial discharges in oilpaper insulation and their applications in pattern recognition

Yongfen L., Junhao L., Ping H., Shengchang J., Yanming L.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 7

219-224

EN

In order to recognize partial discharges (PD), five kinds of typical defects in oil-paper insulation are built and measured with current pulse method, and chaos method is used to research the time series of PD signals. The results revealed that the PD is of obvious chaotic characteristic, and the PD process is chaotic one. The PD patterns can be qualitatively analyzed and recognized by using the chaotic time series of PD and their chaotic attractors. Phase space reconstruction parameters and post-reconstruction chaotic characteristic quantities can be selected to quantify the PD's chaotic characteristics. Verification and comparison on pattern recognition effects of PRPD and CAPD were performed respectively by adopting the neural network of radial basis function (RBF), and the result showed that the effects of both were good and had their own advantages. Besides, statistical operators in PRPD mode and chaotic characteristic quantities in CAPD mode were comprehensively selected as the input vectors of neural network, and the average recognition rate can reach 95%, this result showed that the recognition on PD was improved by a relatively large scale.

PL

Przeprowadzono badania pięciu typowych przypadków defektów izolacji papierowo-olejowej. Sygnały wyładowań niezupełnych przetworzono w szeregi czasowe. Stwierdzono że process ma character chaotyczny. Wykorzystano teorię przebiegów chaotycznych do analizy sygnału i klasyfikacji wad.

3

Time-frequency analysis on pulse current of partial discharge

Wenrong S., Junhao L., Yongfen L., Yanming L.

Przegląd Elektrotechniczny

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2009

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R. 85, nr 7

40-44

EN

This paper introduces a time-frequency analysis (TFA) method of Wigner-Ville distribution (WVD) to analyze partial discharge (PD) pulse current signals with wideband detection for fundamental studies. The mathematical model of WVD is described, and its application in an analysis of PD pulse current signals at DC voltage shows its great advantage.

PL

W artykule zastosowano czasowo-częstotliwościową metodę rozkładu Wignera-Ville (WVD) do analizy prądu impulsowego wyładowania niezupełnego. Przedstawiono model matematyczny WVD oraz przykłady analizy prądu wyładowania.