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Wyświetlanie 1-15 z 29
Tytuł:
The Application of the Correlative Analysis and the Regression Function for Determining Correlations οf the Measurement Results of Acoustic Emission Generated by Partial Discharges
Autorzy:
Boczar, T.
Frącz, P.
Powiązania:
https://bibliotekanauki.pl/articles/1795789.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.58.-e
43.60.-c
43.60.Bf
Opis:
The subject matter of this paper is connected with development of the assessment methods of results obtained at measurements of partial discharges occurring in insulation systems of power transformers using the acoustic emission method. The paper presents the results connected with determining correlation between partial discharge generation voltage and selected descriptors characterizing the emitted signals of acoustic emission in the frequency domain. Authors use the selected descriptors as comparative criteria for recognition of the basic partial discharge forms that may occur in paper-oil insulation of power transformers. The correlation coefficient and regression function were used to determine the correlation degree between the variables under study.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 281-284
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Acoustic Wave Propagation in a Power Transformer Model
Autorzy:
Wotzka, D.
Boczar, T.
Zmarzły, D.
Powiązania:
https://bibliotekanauki.pl/articles/1807760.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
43.28.Js
Opis:
Analyses of acoustic wave propagation in a model power transformer are presented in the paper. The acoustic wave is induced by partial discharges that are simulated at predefined coordinates in the core and winding. Propagation of the numerical calculated acoustic wave is analyzed within the transient state. Achieved results indicate that the space and time distributions of the acoustic pressure depend on the induction position. Furthermore, a greater pressure gradient is observed in domains with higher speed of sound while the largest amplitude occurs at the vicinity of the induction position.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 428-431
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulation of Acoustic Wave Propagating in a Spherical Object Filled with Insulating Oil
Autorzy:
Wotzka, D.
Zmarzły, D.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/1506871.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.60.Lj
Opis:
Results of a numerical simulation of an acoustic wave that propagates in a spherical object filled with insulating oil are presented in the paper. The sinusoidal acoustic wave is generated by an electro-acoustic transducer mounted in the middle of the object. Presented results depict acoustic pressure distribution within the transient and the steady states in a two-dimensional object. Furthermore, comparison of short time simulations adapting different mesh element size is presented.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1272-1275
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristic of Surface Partial Discharges Measured with Ultraviolet Camera
Autorzy:
Frącz, P.
Zmarzły, D.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/1398747.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.79.Pw
79.60.Bm
52.80.Hc
Opis:
The performed research works consider diagnosis of different models of support and bushing insulators. Insulator systems undergo aging processes, which causes deterioration of the insulating properties. In addition, pollutants that accumulate on the surface of high voltage insulators cause further reduction of the insulation properties. Presence of pollutants and high humidity level cause formation of conductive paths, which acts as a source of partial discharges. Presented results depict optical signals, recorded by ultraviolet camera, which were emitted by surface partial discharges occurring on different insulator models. In particular, the effect of the relative value of camera sensitivity on the number of surface partial discharges counts was evaluated. In addition, analysis of the effect of the surface partial discharges generation time on registered counts number was made. The experiments were performed at a constant voltage of $0.9U_{p}$ and for a distance between the HV electrode and GND equal to 10 cm. The experimental study lasted over a period of 30 min, while the measurement steps were done every minute.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 715-718
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of ultrasound signal parameters on sonoluminescence light intensity
Autorzy:
Szmechta, M.
Boczar, T.
Zmarzły, D.
Powiązania:
https://bibliotekanauki.pl/articles/140426.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
diagnostics of insulating oils
sonoluminescence phenomenon
acoustic cavitation
ultrasound signal
acoustic emission Signac
Opis:
Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of Electrical Power Engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn’t prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical Power devices based on non-invasive acoustic emission method.
Źródło:
Archives of Electrical Engineering; 2013, 62, 4; 605-612
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technical Possibilities of Reducing the Sound Pressure Level Emitted into the Environment by a Power Transformer
Autorzy:
Borucki, S.
Boczar, T.
Cichoń, A.
Powiązania:
https://bibliotekanauki.pl/articles/177473.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power transformer
corrected sound pressure level
noise
modernization
Opis:
The subject presented in this paper refers to measurements and assessment of the corrected sound pressure level values (noise) occurring around a medium-power transformer. The paper presents the values of noise accompanying the operation of the power object before and after its modernization, which consisted in repeated core pressing and replacement of the cooling system. The main aim of the research work was the assessment of the influence of the repair work on the noise level emitted into the environment.
Źródło:
Archives of Acoustics; 2011, 36, 1; 49-56
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements and Acoustic Analyses of Infrasound Noise Emitted by Operation of Small, Building Mounted Wind Farm
Autorzy:
Pierzga, R.
Boczar, T.
Wotzka, D.
Powiązania:
https://bibliotekanauki.pl/articles/1401871.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.28.Dm
88.50.gp
88.50.jj
Opis:
Operation of modern wind turbines generates infrasound noise which is known as potentially harmful for humans. In presented study, measurements of infrasound noise generated by operation of five vertical axis, building mounted, small wind turbines were conducted. Measurements were taken in urban area at several points and different distances from the installation. Analyses were performed to determine the level of emitted infrasound noise in vicinity of the installation. Comparative analyses were carried out and the achieved results were referred to the limits of sound pressure intensity level of infrasound signals as specified for the working environment in accordance with the Polish standard PN-Z-01338.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 294-298
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnostics of the Core Mechanical Construction Based on Vibroacoustic Measurements and Distribution of Temperature Field in Transformer Magnetic Circuit
Autorzy:
Borucki, S.
Cichon, A.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/1401874.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.-r
43.40.Vn
43.58.Wc
Opis:
Subject matter of this article concerns the results of research works on the development and use of the vibroacoustic method to evaluate technical state of transformer cores. The article presents obtained measurement results of transformer mechanical vibration for two cases of its operation: with twisted and loosened core. In order to demonstrate negative effects of operating a transformer with a loosened core, this publication presents thermographic images showing temperature distribution on its magnetic core. The article characterises the examined transformer, employed measurement system and methodology of the completed experiment. The vibroacoustic and thermographic measurements were carried out during idle work of the transformer. Core vibration was registered for three measurement axes: 0X, 0Y and 0Z. Completed tests have proven that loosened screws pressing the core cause evident increase in the value of magnetic core vibration acceleration. At the same time, the temperature rises by more than 25%.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 306-309
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency and Time-Frequency Analysis of Acoustic Cavitation Noise in Insulating Oils
Autorzy:
Szmechta, M.
Boczar, T.
Frącz, P.
Powiązania:
https://bibliotekanauki.pl/articles/1493273.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.60.Lj
43.40.Le
Opis:
The paper presents some observations of ultrasound induced cavitation phenomenon in a mineral insulating oil. The acoustic cavitation phenomenon was generated at different signal frequencies and rms voltage value supplied to round piezoelectric transducers. Used transducers have created a high energy acoustic field in prepared insulating oil samples. The acoustic emission signal contains a broad-band noise and a fundamental frequency component and its harmonics, produced by the direct driving acoustic field. The paper presents the spectral analysis of acoustic emission signal observed during acoustic cavitation in insulating oils. To emphasize the changes in acoustic cavitation intensity also time-frequency analysis was used and some spectrograms were evaluated. The measurement uncertainty of some frequency-rms voltage pairs was very unfavorable. The main application expected with created cavitation measurement system is to develop a diagnostic tool for the aging of oil, based on the hypothesis that the measured cavitation intensity and spectrum could be affected by aging. Previous published measurements showed some relationship between insulating oil aging process and changes of acoustic emission of cavitations.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 744-747
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical Model and Numerical Analysis of~AE Wave Generated by Partial Discharges
Autorzy:
Wotzka, D.
Boczar, T.
Fracz, P.
Powiązania:
https://bibliotekanauki.pl/articles/1493290.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.Le
02.60.Lj
Opis:
Paper presents definition of a mathematical model describing acoustic emission signals generated by partial discharges occurring in oil immersed electric power transformers. Time runs, power spectral density graphs and spectrograms of acoustic emission signals generated in experiments, performed under laboratory conditions, and of equivalent signals, calculated on the basis of the mathematical model, are presented. Furthermore, results of numerical simulations of acoustic pressure distribution inside a tank filled with insulation oil are presented in the paper. In the center of the tank acoustic emission wave sources were placed, each generating signals described by the model developed.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 767-771
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling and Experimental Verification of Ultrasound Transmission in Electro Insulation Oil
Autorzy:
Wotzka, D.
Cichoń, A.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/177158.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasound transmission
numerical simulations
electro-insulation oil
Opis:
A verification study of ultrasound transmission numerical simulation results with experiment results is presented in this paper. The work considers a model of a transformer tank which is filled with electro insulating oil. In the experiment, performed under laboratory conditions, an ultrasound wave is generated by a piezoelectric transducer that is fixed in the centre of the tank and measured by another transducer mounted inside the tank at three distances: 10, 20 and 30 cm from the sound source. The transducer is able to measure and generate acoustic waves in the ultrasound frequency band up to 1 MHz. The simulation considers numerical calculation of acoustic pressure distribution inside the tank in which acoustic source emits waves with frequency equal to 100 kHz. Verification analysis has confirmed consistency of the numerically calculated values with the measurement results.
Źródło:
Archives of Acoustics; 2012, 37, 1; 19-22
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Optical Radiation Generated by Partial Discharges on Insulators
Autorzy:
Frącz, P.
Boczar, T.
Borucki, S.
Powiązania:
https://bibliotekanauki.pl/articles/1366318.pdf
Data publikacji:
2014-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
42.79.Pw
52.80.Hc
Opis:
Results of measurements of optical radiation emitted by partial and complete electrical discharges occurring on a bushing insulator model placed in air are presented in the article. Registration was performed using a spectrophotometer, enabling for measurement of optical radiation in the range from 270 to 1700 nm. Detailed characteristics of spectrophotometer are presented in our previous paper. The primary objective of the laboratory tests was to evaluate the impact of supply voltage changes in the range from 0 to 0.99 $U_{b}$ (breakdown voltage) on the intensity and spectral character of the optical radiation emitted by partial discharges generated on the porcelain insulation surface of the bushing insulator. In the scope of studies analyzes of the effects of voltage changes on the obtained spectral waveforms were performed, whereby voltage increase and reduction was examined separately. Additionally, measurements and analyzes carried out included impact estimation of the time period as the voltage was applied to the high-voltage electrodes on the course of optical phenomena related to the generation of partial discharges.
Źródło:
Acta Physica Polonica A; 2014, 125, 6; 1360-1366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on Infrasound Noise Emitted by Wind Turbines of Large Power
Autorzy:
Boczar, T.
Malec, T.
Wotzka, D.
Powiązania:
https://bibliotekanauki.pl/articles/1418027.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.28.Dm
07.10.-h
46.40.-f
43.50.-x
43.50.+y
Opis:
The subject area of this article applies to study of infrasound signals generated by the work of modern wind turbines. Infrasound noise measurements were conducted in accordance with assumptions of the EN 61400-11 standard. The object of study was a newly commissioned wind farm with a total electrical power equal to 30 MW. The considered power station consisted of 15 new wind turbines, each with a capacity of 2 MW. Scope of the analysis performed included designation of time runs, depicting temporal changes, and designation of frequency spectra of the recorded infrasound signals. Evaluation of the impact of changes in wind speed was made. Moreover, the scope of analysis, performed in this field, concerned assessment of the impact on the obtained results values of meteorological parameters related to the applied measurement system. Values obtained from measurements were related to and compared with the limits specified in standards and regulations existing in this field.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 850-853
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Interference Signals Generated by Vibroacoustic Vibrations of Transformer Cores
Autorzy:
Boczar, T.
Borucki, S.
Cichoń, A.
Powiązania:
https://bibliotekanauki.pl/articles/1199078.pdf
Data publikacji:
2014-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
42.79.Pw
52.80.Hc
Opis:
The article deals with the subject matter referring to the interference that may accompany measurements of vibroacoustic signals, generated by electric power transformers, taken by using the acoustic emission method under industrial conditions. Paper concerns measurement and analysis of internal, acoustic type disturbances, including the magnetostrictive vibrations of plate sets within the transformer core, caused by changes in the magnetic flux. Paper presents measurement results of acoustic interfering signals and results of analyses made in the frequency and time-frequency domains. Power spectral density, MUSIC pseudospectra, two- and three-dimensional short time Fourier transform spectrograms, continuous wavelet transform scalograms, discrete wavelet transform, and quantities of energy transferred are included in the paper.
Źródło:
Acta Physica Polonica A; 2014, 125, 6; 1355-1359
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnosis of the Non-Concurrent Operation of the On-Load Tap Changer Contacts by the Acoustic Emission Method
Autorzy:
Cichoń, A.
Borucki, S.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/177044.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power transformer
on-load tap changers
acoustic emission method
Opis:
On-load tap changers (OLTC) are some of the main transformer elements that make voltage adjustment in a power network possible. Their failures often cause shutdowns of distribution transformers. The paper presents research work aimed at the assessment of the technical condition of OLTCs by the acoustic emission method (EA). This method makes the OLTC diagnosis possible without the need of disconnecting the transformer from the system. The measurements were taken in laboratory conditions. The influence on the operation non-concurrence of the power tap changer contacts on the AE registered signals has been investigated. The signals registered were subjected to analyses in the time and time-frequency domains. The result analysis in the time domain was carried out using the Hilbert transform and calculating characteristic times for the particular runs. A short-time Fourier transform was used for the assessment of results in the time-frequency do- main.
Źródło:
Archives of Acoustics; 2011, 36, 4; 823-830
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 29

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