Wyniki wyszukiwania - Biblioteka Nauki

1

The use of mathematical statistics for the description of the acoustic emission pulses generated by partial discharges

100%

Boczar T. , Wolny S.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2004

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tom Vol. 40, nr 15

301-306

EN

The subject matter of this paper deals with the improvement of the acoustic emission (AE) method in diagnostics of insulation systems of power appliances. The paper presents the results of the statistical analysis of the AE pulses generated by the setups modeling basic partial discharge (PD) forms that can occur in oil insulation systems. Especially for each of the samples representing PD forms under study, the runs of histograms and the corresponding density curves, and then the values of indices being the measures of location, dispersion, asymmetry and concentration of the AE pulses measured were determined. Moreover, the following plots were presented: scatter plot, symmetry plot and box plot, In Summing-up the results of the comparative analysis of descriptive statistics for six forms of partial discharges were presented.

2

Corona between two conductors being in motion

100%

Szadkowski M.

Poznan University of Technology Academic Journals. Electrical Engineering

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2009

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tom No 59

161-170

EN

Corona is one of the best recognizable partial discharges. Its parameters, when corona appears between two motionless electrodes, are enough well described. The article contains chosen measuring results concerned first of all corona between two parallel conductors for different air clearances when such electrodes change suddenly these reciprocal positions.

3

Experience with optical partial discharge detection

100%

Muhr M. , Schwarz R.

Materials Science Poland

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2009

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tom Vol. 27, No. 4/2

1139--1146

EN

Partial discharge (PD) diagnostics was used to evaluate electrical insulations of high voltage equipment as a quality control and to detect insulation deterioration. Improvements, new developments as well as lower costs of sensors, electronics and processing units are some reasons for the increasing usage of PD measurements. The paper presents investigations in the area of optical partial discharge measurement technique. In an overview, PD measurement systems were presented, advantages and disadvantages of the optical method were discussed. An unconventional optical partial discharge detection system was developed and comparative measurements to a conventional electrical PD measurement system were accomplished. The system was tested by using a PD source in air or alternatively in oil to evaluate the sensitivity and the impulse behaviour in correlation to the conventional measurement technique.

4

Experience with optical partial discharge detection.

100%

Muhr M. , Schwarz R.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2007

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tom Vol. 46, nr 19

26-29

EN

Partial discharge measurement is used to evaluate different electrical insulations of high voltage equipment as a quality control and to detect insulation deterioration. Improvements, new developments as well as the lower costs of sensors, electronics and processing units are some reasons for the increasing usage of PD diagnostic. This paper presents investigations in the area of optical partial discharge measurement technique. In an overview different PD measurement systems were presented, advantages and disadvantages of the optical method were discussed. An unconventional optical partial discharge detection system was developed and comparative measurements to an conventional electrical PD measurement system were accomplished. The system was tested in the laboratory by using a PD source in air or alternatively in oil to evaluate the sensitivity and the impulse behaviour in correlation to the conventional measurement technique.

5

Application of a Phase Resolved Partial Discharge Pattern Analysis for Acoustic Emission Method in High Voltage Insulation Systems Diagnostics

80%

Kunicki M. , Cichoń A.

Archives of Acoustics

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2018

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tom Vol. 43, No. 2

235--243

EN

An alternative method for analysis of acoustic emission (AE) signals generated by partial discharges (PD), based on a correlation between voltage phase run and AE pulses, so called phase resolved PD pattern (PRPD), is presented in the paper. PRPD pattern is a well-known analysis tool commonly used in such PD diagnostic methods as conventional electrical and UHF ones. Moreover, it yields various signal analysis abilities and allows a direct correlation indication between measurement results achieved using different methods. An original PRPD measurement methodology applied for AE method as well as some exemplary measurement results and further data analysis capabilities are presented in the paper. Also a comparative analysis of PRPD patterns achieved using various measurement methods and different PD source configurations have been investigated. All presented experiments were done under laboratory conditions using PD model sources immersed in the insulation oil. The main purpose of the presented research is to indicate an all-embracing analytical tool that yields an ability to direct comparison (qualitative as well as quantitative) of the AE measurement results with other commonly applied PD measurement methods. The presented results give a solid fundamental for further research work concerning a direct correlation method for AE and other described in the paper diagnostic techniques, mainly in order to continue PD phenomena analysis and assessment in real life high voltage apparatus insulation systems under normal onsite operation conditions.

6

Wpływ ilości źródeł wyładowań niezupełnych powierzchniowych na wyniki analizy częstotliwościowej i czasowo-częstotliwościowej sygnałów emisji akustycznej

80%

Witkowski P. , Kurtasz P. , Boczar T. , Cichoń A. , Borucki S.

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2010

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tom z. 65

71-79

PL

Tematyka przedstawionego artykułu jest związana z doskonaleniem metody emisji akustycznej (EA) w zastosowaniu do diagnostyki układów izolacyjnych transformatorów elektroenergetycznych opartej na pomiarze i ocenie generowanych wyładowań niezupełnych (WNZ). Natomiast celem szczególnym przeprowadzonych badań, których wyniki są omawiane w artykule, było określenie możliwości rozpoznawania podstawowych form wyładowań niezupełnych (WNZ) w przypadku występowania wieloźródłowych wyładowań jednego typu. Wykonane badania dotyczyły wyładowań niezupełnych najczęściej występujących w urządzeniach elektroenergetycznych, jakimi są wyładowania powierzchniowe (WNZP). Określenie wpływu ilości źródeł (WNZP) ma na celu potwierdzenie przydatności metody EA jako źródła informacji na temat stanu diagnozowanej izolacji papierowo-olejowej. Zarejestrowane sygnały EA poddano analizie w dziedzinie częstotliwościowej, jak również czasowo-częstotliwościowej. Wyniki analizy częstotliwościowej przedstawiono jako widmo gęstości amplitudy, a rezultaty przekształceń czasowo-częstotliwościowych przedsta-wiono za pomocą dwu- i trójwymiarowych spektrogramów widma gęstości mocy.

EN

Partial discharge is a local electrical discharge, which can be compared with microeksplosion inside dielectric. In this paper, results of the research on acoustic emission (AE) signals, which arise during the partial discharges (PDs) generation inside transformer tank filled with synthetic oil, are described. The signals registered as a function of time are then transformed into the frequency domain using FFT and STFT.

7

Application of the Acoustic Emission Method for Diagnosis of On-Load Tap Changer

80%

Majchrzak H. , Cichoń A. , Borucki S.

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tom Vol. 42, No. 1

29--35

EN

This paper provides an example of the application of the acoustic emission (AE) method for the diagnosis of technical conditions of a three-phase on-load tap-changer (OLTC) GIII type. The measurements were performed for an amount of 10 items of OLTCs, installed in power transformers with a capacity of 250 MVA. The study was conducted in two different OLTC operating conditions during the tapping process: under load and free running conditions. The analysis of the measurement results was made in both time domain and time-frequency domain. The description of the AE signals generated by the OLTC in the time domain was performed using the analysis of waveforms and determined characteristic times. Within the time-frequency domain the measured signals were described by short-time Fourier transform spectrograms.

8

Radio frequency current transformers as sensors for partial discharge measurement

80%

Kandora W.

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2011

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tom z. 66

39-40

EN

This paper describes test results of the laboratory study on the partial discharge measurements with use of capacitance and inductance sensors.

9

The influence of pressboard barriers on acoustic emission signal generated by partial discharges in a power transformer

80%

Sikorski W. , Staniek P. , Siodła K.

Poznan University of Technology Academic Journals. Electrical Engineering

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2007

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tom No 56

155-164

EN

The paper presents the results of investigation how pressboard barriers influence on acoustic emission signals parameters generated by partial discharges occurring in a power transformer. Additionally, the discussion on possibilities of detection of strongly attenuated (noised) discharges registered in industrial conditions with the use of acoustic emission method was conducted.

10

Detection and measurement of the optical signals emitted by the partial discharges

80%

Fedorowicz P.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2014

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tom z. 70

17-18

EN

This paper presents possibilities of detection and measurement of the optical signals emitted by the partial discharges in the infrared, visible and ultraviolet spectrum using optical spectroscopy, thermographic and ultraviolet cameras as well as photographic techniques.

11

Modeling of partial discharge characteristics

80%

Kunicki M.

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2017

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tom z. 75

47--48

EN

A comparative analysis on different models applications for real life partial discharge (PD) characteristics approximation is presented in the paper. PD is generated in oil insulation under laboratory conditions. Typical discreet phase domain distributions commonly used for PD analysis are modeled by proposed continuous functions. Among various investigated models Gauss (GM) and sum of sinus functions (SM) based models are confirmed to be optimal solution.

12

X-rays generated by partial discharges in atmospheric air

80%

Nagi Ł.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2014

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tom z. 70

73-75

EN

This article presents an analysis of the phenomenon of X-ray generated from partial discharges. The measurement data have been analyzed in MATLAB environment. Previous studies showed the relationship between the increase in voltage between electrodes, and both, the energy and the number of ionizing acts. In another study, the modified initial conditions confirmed the existence of X-ray radiation generated by the PD. The changes were related to the spark gap material.

13

Estimation of the ability of using time-frequency descriptor in Optimized Multi-Comparative Algorithm

80%

Kurtasz P.

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2011

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tom z. 66

47-48

EN

In the hereof paper was presented the efficacy classification distribution of Optimized Multi-Comparative Algorithm (OMA) with implemented time-frequency descriptor with a function of changing the amount of intervals in time domain. Algorithm OM was constructed in order to enable the classification of eight main partial discharges (PD) classes.

14

Badania diagnostyczne w eksploatacji transformatorów

80%

Krawiec A. , Polak P.

Wiadomości Elektrotechniczne

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2013

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tom R. 81, nr 2

35-40

PL

Przedstawiono wyniki specjalistycznych badań przeprowadzonych na wybranej grupie transformatorów o górnym napięciu 110 kV.

EN

The paper presents results of specialist tests conducted on special group of transformers with primary voltage 110 kV.

15

Verification of the effectiveness of the selected clustering method used to analyse acoustic emission from partial discharges

80%

Łuczak J.

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2017

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tom z. 75

51--52

EN

In this paper author describes idea of verification data reproduction in data clustering methods for analysis of acoustic emission generated by basic forms of partial discharges.

16

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

80%

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

Przegląd Elektrotechniczny

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2011

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tom 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.

17

Typical patterns of partial discharges acquired by measurements on real models of cavity in solid dielectric and instrument transformers.

80%

Laurenc J. , Martinek P. , Pihera J.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2007

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tom Vol. 46, nr 19

245-249

EN

This paper presents experimental results which were obtained during measuring of partial discharges on real models of cavity in solid dielectric. The idea for this study was to acquire characteristic patterns of partial discharges which belong to basic configurations of artificially created cavities in solid dielectric between plane electrodes. Digital patterns of partial discharges acquired by measurements on mentioned models and electrical equipments had become the basis for so-called partial discharge dictionary. Some fundamental information about principles of the electrical wideband measuring method of partial discharges is also briefly presented in the paper. The results of diagnostics measurements of partial discharges made on voltage instrument transformers with solid insulation are placed in the second part of the paper. The measurements performed on relatively extent number of specimens provided detailed survey of the transformers insulating system quality

18

A study on the design of a planar loop sensor in the partial discharge diagnosis of underground power cables.

80%

Lim K. J. , Shin D. H. , Lwin K. S. , Park N. J.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2007

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tom Vol. 46, nr 19

274-277

EN

The objective of this paper is to effectively detect partial discharges in underground power cables. In this field, we have been usually applied several sensors for such partial discharges. This study used a type of beyond compare antenna based on the influence of background noises. Also, we designed a new structure that is able to easily apply in the adhesion of planar loop types for underground power cables in measurement sensitiveness elevation. A high frequency simulation tool (CST-MWS) was applied to the antenna used in this study, and it was used to evaluate certain characteristics. We fabricated an antenna using the simulation data obtained from a specific test. After checking the sensitivity of this antenna in the Lab, it was tested in an actual site. This paper analyzed the data as a part of time and frequency domain using an oscilloscope and spectrum analyzer, respectively.

19

Onsite diagnostics and condition evaluation of rotating machines.

80%

Muhr M. , Schwarz R. , Sumereder C.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2007

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tom Vol. 46, nr 19

30-33

EN

In this paper the focus is laid on the diagnostic methods for rotating machines with respect to condition evaluation. In an overview the diagnostic measurements were presented and discussed. The most important factors for evaluation criterions were insulation resistance, dissipation factor, partial discharge and voltage withstand test. Some of these test results deliver absolute parameters and some have to be evaluated relatively. For the condition evaluation the absolute parameters deliver the information about the compliance of threshold values (passed/failed) to guarantee save operation within the next service interval. The relative parameters are helpful to find weak points in the electric insulation system, e.g. with PD pattern recognition the source of failures can be detected. In dependence of the maintenance strategy the results of the measurements and condition evaluation give helpful information for the decision of the further operation or if there have to be done any measures as overhaul, servicing or repair.

20

Use of PDS100 analyzer for detection of partial discharges

80%

Urbaniec I.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2014

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tom z. 70

97-100

EN

The article presents results of partial discharge (PD) measurements conducted in lab conditions, with the use of the HV testing apparatus, where PDS100 analyzer was used for detection.