Piekary Śląskie, Poland
Piekary Śląskie, Poland

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Jurcik J.,University of Zilina | Gutten M.,University of Zilina | Korenciak D.,University of Zilina | Zukowski P.,Lublin University of Technology | And 4 more authors.
10th International Conference, ELEKTRO 2014 - Proceedings | Year: 2014

In paragraph are presented the results of research based on the AC conductivity of the wet oil-impregnated insulating paper, depending on the moisture content and temperature of the samples. This is a new experimental method, which converts the results from the FDS to the reference temperature of 293.15 K (20 ° C). Takes account of the activation energy for conduction and relaxation time © 2014 IEEE.


Sebok M.,University of Zilina | Zukowski P.,Lublin University of Technology | Koltunowicz T.N.,Lublin University of Technology | Kierczynski K.,Lublin University of Technology | And 2 more authors.
10th International Conference, ELEKTRO 2014 - Proceedings | Year: 2014

The article presents the results of research based on the DC electrical conductivity of wet paper depending on the moisture content and temperature of the samples. The change of moisture content does not change the activation energy of conductivity. The conductivity is performed by the hopping mechanism between the nearest possible holes which are formed in the material with nanodrops of water by the plotting of theoretical dependence that accurately describes the dependence of the conductivity of the water content and temperature. Medium size of nanodrops was about 1.5 nm, and the composition contains about 220 molecules of water. © 2014 IEEE.


Zukowski P.l,Lublin University of Technology | Koltunowicz T.N.,Lublin University of Technology | Kierczynski K.,Lublin University of Technology | Subocz J.,West Pomeranian University of Technology | Szrot M.,Power Engineering Research Center Ltd.
Cellulose | Year: 2015

This article presents results on the DC conductivity of moist pressboard impregnated with insulating oil and its dependence on the moisture and temperature of the samples. The transfer of charges was found to take place because of electron hopping between potential wells produced by water nanodrops. The average dimension of the nanodrops was around 2.32 nm, forming approximately 220 water molecules. © 2015, The Author(s).


Zukowski P.,Lublin University of Technology | Koltunowicz T.N.,Lublin University of Technology | Kierczynski K.,Lublin University of Technology | Subocz J.,Lublin University of Technology | And 4 more authors.
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2015

The paper presents research results of testing AC conductivity in a moist oilimpregnated electric insulation pressboard, depending on the moisture content level and temperature of the samples. A new method has been elaborated for converting experimentally obtained dependences from frequency-domain spectroscopy (FDS) to the reference temperature of 293 K (20 /dpl deg/C). Activation energy values have been determined for the conduction and relaxation time. It has been found the conductivity is realized by electron tunnelling between potential well formed by water molecules contained in the structure of moist cellulose. © 1994-2012 IEEE.


Zukowski P.,Lublin University of Technology | Koltunowicz T.N.,Lublin University of Technology | Kierczynski K.,Lublin University of Technology | Rogalski P.,Lublin University of Technology | And 5 more authors.
Cellulose | Year: 2016

The paper presents an analysis of test results by Frequency Domain Spectroscopy (FDS) of the loss tangent (tgδ) in electrotechnical pressboard impregnated with insulating oil and containing nanoparticles of water depending on the frequency of alternating current, sample temperature and degree of moisture. We found tgδ reduction in areas of low and ultra-low frequency. It is associated with relaxation due to the hopping conductivity (tunnelling) of electrons between moisture nanoparticles occurring in the cellulose impregnated with insulating oil. In frequency areas close to the local minimum of tgδ and higher, relaxation does not depend on the moisture content and is associated with other polar molecules which are part of the cellulose. We developed a new method converting experimental frequency dependence of the loss angle tangent, measured by the FDS method to the reference temperature of 293 K (20 °C), using the exponential dependence of the relaxation time on the temperature, was developed. The activation energy of the relaxation time was determined based on the loss angle tangent of moist electrotechnical pressboard impregnated with insulating oil. It was found that the variation in moisture content in the composite cellulose–mineral oil–water nanoparticles do not cause changes in the activation energy of the relaxation time. The conversion of experimental frequency dependence of the loss angle tangent determined by the FDS method to the reference temperature of 293 K (20 °C) eliminates the temperature dependence in the areas of ultra-low and low frequencies occurring in the runs made directly on the basis of the measurement results. After calculating the frequency dependence of the loss angle tangent to the reference temperature, all that remains is its dependence on the moisture content. © 2016 The Author(s)


Zukowski P.,Lublin University of Technology | Koltunowicz T.N.,Lublin University of Technology | Kierczynski K.,Lublin University of Technology | Rogalski P.,Lublin University of Technology | And 5 more authors.
Cellulose | Year: 2016

The paper presents results of testing permittivity of an oil-impregnated electric pressboard containing water nanoparticles depending on AC frequency, moisture content level and the temperature of samples. A new method has been developed for converting experimentally obtained frequency dependences of permittivity determined with the frequency-domain spectroscopy (FDS) to the reference temperature of 293 K (20 °C) using exponential dependence of the relaxation time versus temperature. Activation energy of the permittivity relaxation time has been determined for a moist oil-impregnated electric insulation pressboard. It has been established that variations of the moisture content level in a composite of cellulose, mineral oil, and water nanoparticles do not cause any changes in the relaxation time activation energy value, neither in energy states of electrons in potential wells nor in the structure of water nanoparticles. It has been also found that the conversion of experimentally obtained permittivity versus frequency dependences determined with the FDS method to the reference temperature of 293 K (20 °C) eliminates temperature dependences that occur in characteristics based directly on measurement results. Once the relative permittivity is converted to the reference temperature it is only its dependence on the moisture content level that remains. © 2015, The Author(s).


Zukowski P.,Lublin University of Technology | Koltunowicz T.N.,Lublin University of Technology | Kierczynski K.,Lublin University of Technology | Subocz J.,West Pomeranian University of Technology | And 2 more authors.
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2014

The paper presents results of investigations of the effect of moisture content and temperature on DC conductivity of the impregnated pressboard. It has been found that the conductivity of the impregnated pressboard is a function of activation energy, moisture content and temperature. It has been found that moisture content ranging from 1.4% to 6.4% do not cause any changes in the conductivity activation energy whose value is ΔWav = (0.853±0.071) eV. On the other hand water content strongly influences the value of DC conductivity. It has been also found that the conductivity is determined by electron hopping between the closest located potential wells formed by water molecules in the oil-impregnated cellulose structure. For the experimentally obtained dependences of conductivity vs. moisture content and temperature theoretical ones have been determined to describe the experimental results. Based on the research results, a localization radius of the water molecule valence electron that coincides with the O2- ion radius has been determined. The obtained results concerning DC conductivity vs. moisture level and temperature dependence of an electric insulation pressboard can make a basis for the identification of the amount of moisture accumulated in solid elements of a power transformer paper-oil insulation.


Prokopchuk N.,Belarusian State University | Luhin V.,Belarusian State University | Vishnevskii K.,Lublin University of Technology | Shashok Z.,Power Engineering Research Center Ltd | And 2 more authors.
High Temperature Material Processes | Year: 2013

Nanofibers from chitosan were obtained by the NANOSPIDER technology. The structure of the nanofiber layer was analyzed by the method of scanning microscopy on a JSM-5610 LV JEOL. It is found that the most reasonable concentration of chitosan (in the test interval) is 2.0 wt.%. In this case, the process is stable, and nanofibers are formed with a diameter of up to 250 nm. Based on these results, the optimum technological parameters of the electrospinning used for manufacturing high-quality uniform nanofiber coating have been determined. However, the use of different types of chitosan, as well as substrates of differing nature and structure, may require adjustment of these parameters. © 2013 by Begell House, Inc.


Romanyuk F.,Belarusian National Technical University | Novash I.,Belarusian National Technical University | Loman M.,Belarusian National Technical University | Wegierek P.,Lublin University of Technology | Szrot M.,Power Engineering Research Center Ltd.
Przeglad Elektrotechniczny | Year: 2014

Comparison of results of mathematical modeling and field tests of a transformer differential protection is presented in this paper. An inrush current mode, external two-phase and three-phase faults are considered. Proposed mathematical model can be used to test differential protection in different modes of transformer operation.

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