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Measurement uncertainty in diagnostics of insulating materials
Kamenická, Zuzana ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with measurement capacity and dissipation factor of capacitor with real dielectric in frequency range 20 Hz to 30 MHz. Liquid and solid dielectrics are measured by LCR instruments and by test fixtures, both from company Agilent. Relative permittivity and loss number are calculated for different instruments settings. The general aim is to specify the influence of parameters as frequency, voltage, integration time and thickness of material on the uncertainties of primary and secondary quantities for measurement.
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Dielectric properties of liquid insulators
Jahn, Michal ; Starý, Jiří (referee) ; Špinka, Jiří (advisor)
This master‘s thesis deals with measurement of liquid dielectric materials (insulators). Above all, it is the different kinds of clean and drinking water, but also transformer oils. There was done theoretical information retrieval about the given topic in this project and on the basis of theory there were realized the relevant measurements of selected properties of liquid dielectric, such as permittivity, capacitance, loss number, conductivity, but also temperature dependence of these parameters. The measurements were realized with the help of product manufactured at the faculty FEKT VUT and with the help of measuring system AGILENT 16452A. The measured results were evaluated, graphically processed and compared.
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Dielectric Properties of Vegetable Oils for Electrical Engineering
Spohner, Milan ; Mejzlík,, Miroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation thesis deals with the analysis of prospective environmentally compatible electrical insulating fluids for electrical engineering in relation to their chemical structure. The thesis starts with the overview of the current state of the art and of the latest trends in the use of synthetic and biodegradable natural oils. In the experimental part were studied these oils: mineral oils, rapeseed oil, sunflower oils, soybean oil, methyl oleate, peanut oil, MCT oil, castor oil and other. Dielectric properties were measured using LRC meter Agilent 4980A including dielectric liquid test fixture Agilent 16452A and also by the Novocontrol Alpha-A analyzer. Electrical properties are presented in the frequency range 10 mHz – 1 MHz range in the temperature interval 253 K to 363 K. The work goes on with the study of the suitability of individual oils for lower temperature, including the impact of the chemical structure and formulation on electrical properties.
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Study of alternative electroinsulating liquids properties
Bannert, Tomáš ; Hylský, Josef (referee) ; Frk, Martin (advisor)
This bachelor´s thesis is dealing with the study of alternative electrical insulating properties of the materials used in the electronics industry, particularly liquids based on natural esters and especially their constituents in the form of higher fatty acids and esters. The work is divided into theoretical and practical part. The theoretical part deals with the characterization of vegetable oils, their constituents and mineral oils, their comparison in terms of electrical and non-electrical properties and current state of the use of vegetable oils and their constituents in the electronics industry. Further it’s dealing with analysis of diagnostic methods for these characteristics. In the experimental part were analyzed electrical and non-electrical properties of selected samples of vegetable oils, their constituents and mineral oils such as the density, the dynamic viscosity and the complex permittivity and its parts as relative permittivity and loss number. Evaluations of the results of each group are compared with each other.
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Time-domain Dielectric Spectroscopy of Carboxymethylcellulose
Palai-Dany, Tomáš ; Lelák, Jaroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation deals with the time-domain dielectric relaxation spectroscopy of carboxymethylcellulose. The main attention was paid to the experimental part of research, mainly to the design and subsequent development of an experimental setup for the measurement of discharge currents and for their processing and analysis. The subject of the measurement is carboxymethylcellulose (CMC), which is a simple polysaccharide used in wide range of applications, among else also in biomedical engineering. The study of CMC properties has required the development of a new experimental set-up of original design, which includes the equilibration (short-circuiting) of a sample before the measurement, charging and discharging at defined time intervals, switching between these two modes, recording of measurement, adjustments and processing of measured signals up to Fourier transformation into the frequency domain and, finally, calculation of complex permittivity of the sample. The frequency dependence of complex permittivity or its imaginary part, obtained by Fourier transformation of discharge current in time domain, is then referred to as the dielectric spectrum. In view of the fact that current measurements were done at very low levels of measured signal (below 10-12 A) the whole measurement was no easy matter. The framework of the work also necessitated studies and subsequent resolution of problems associated with shielding, grounding, presence of noise and sensitivity to various ambient influences. The research work focused on a reliable and trustworthy measurement of very low discharge currents and, subsequently, mathematical processing of noise present in them, i.e., operations with the original, experimentally established signal in time domain, leading in principle to a digital filtration of measured dielectric data. A further pursued objective is the explanation of dielectric parameters of tested carboxymethylcellulose sample in the widest possible frequency spectrum. The integral part of the research was the selection and application of the method for the transformation of the adjusted signal to the frequency domain. The experimental works, including data processing, were carried out in the Department of Physics, Brno FEEC BUT. Measurements were done with Keithley 617 Electrometer, HP4284A Frequency Analyzer and Janis CCS-400-204 cryogenic system. The results were completed with results obtained at the V Department of Experimental Physics, Centre for Electronic Correlations and Magnetism, University of Augsburg, Germany.
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Dielectric Properties of Vegetable Oils for Electrical Engineering
Spohner, Milan ; Mejzlík,, Miroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation thesis deals with the analysis of prospective environmentally compatible electrical insulating fluids for electrical engineering in relation to their chemical structure. The thesis starts with the overview of the current state of the art and of the latest trends in the use of synthetic and biodegradable natural oils. In the experimental part were studied these oils: mineral oils, rapeseed oil, sunflower oils, soybean oil, methyl oleate, peanut oil, MCT oil, castor oil and other. Dielectric properties were measured using LRC meter Agilent 4980A including dielectric liquid test fixture Agilent 16452A and also by the Novocontrol Alpha-A analyzer. Electrical properties are presented in the frequency range 10 mHz – 1 MHz range in the temperature interval 253 K to 363 K. The work goes on with the study of the suitability of individual oils for lower temperature, including the impact of the chemical structure and formulation on electrical properties.
|
|
|
Study of alternative electroinsulating liquids properties
Bannert, Tomáš ; Hylský, Josef (referee) ; Frk, Martin (advisor)
This bachelor´s thesis is dealing with the study of alternative electrical insulating properties of the materials used in the electronics industry, particularly liquids based on natural esters and especially their constituents in the form of higher fatty acids and esters. The work is divided into theoretical and practical part. The theoretical part deals with the characterization of vegetable oils, their constituents and mineral oils, their comparison in terms of electrical and non-electrical properties and current state of the use of vegetable oils and their constituents in the electronics industry. Further it’s dealing with analysis of diagnostic methods for these characteristics. In the experimental part were analyzed electrical and non-electrical properties of selected samples of vegetable oils, their constituents and mineral oils such as the density, the dynamic viscosity and the complex permittivity and its parts as relative permittivity and loss number. Evaluations of the results of each group are compared with each other.
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Time-domain Dielectric Spectroscopy of Carboxymethylcellulose
Palai-Dany, Tomáš ; Lelák, Jaroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation deals with the time-domain dielectric relaxation spectroscopy of carboxymethylcellulose. The main attention was paid to the experimental part of research, mainly to the design and subsequent development of an experimental setup for the measurement of discharge currents and for their processing and analysis. The subject of the measurement is carboxymethylcellulose (CMC), which is a simple polysaccharide used in wide range of applications, among else also in biomedical engineering. The study of CMC properties has required the development of a new experimental set-up of original design, which includes the equilibration (short-circuiting) of a sample before the measurement, charging and discharging at defined time intervals, switching between these two modes, recording of measurement, adjustments and processing of measured signals up to Fourier transformation into the frequency domain and, finally, calculation of complex permittivity of the sample. The frequency dependence of complex permittivity or its imaginary part, obtained by Fourier transformation of discharge current in time domain, is then referred to as the dielectric spectrum. In view of the fact that current measurements were done at very low levels of measured signal (below 10-12 A) the whole measurement was no easy matter. The framework of the work also necessitated studies and subsequent resolution of problems associated with shielding, grounding, presence of noise and sensitivity to various ambient influences. The research work focused on a reliable and trustworthy measurement of very low discharge currents and, subsequently, mathematical processing of noise present in them, i.e., operations with the original, experimentally established signal in time domain, leading in principle to a digital filtration of measured dielectric data. A further pursued objective is the explanation of dielectric parameters of tested carboxymethylcellulose sample in the widest possible frequency spectrum. The integral part of the research was the selection and application of the method for the transformation of the adjusted signal to the frequency domain. The experimental works, including data processing, were carried out in the Department of Physics, Brno FEEC BUT. Measurements were done with Keithley 617 Electrometer, HP4284A Frequency Analyzer and Janis CCS-400-204 cryogenic system. The results were completed with results obtained at the V Department of Experimental Physics, Centre for Electronic Correlations and Magnetism, University of Augsburg, Germany.
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Dielectric properties of liquid insulators
Jahn, Michal ; Starý, Jiří (referee) ; Špinka, Jiří (advisor)
This master‘s thesis deals with measurement of liquid dielectric materials (insulators). Above all, it is the different kinds of clean and drinking water, but also transformer oils. There was done theoretical information retrieval about the given topic in this project and on the basis of theory there were realized the relevant measurements of selected properties of liquid dielectric, such as permittivity, capacitance, loss number, conductivity, but also temperature dependence of these parameters. The measurements were realized with the help of product manufactured at the faculty FEKT VUT and with the help of measuring system AGILENT 16452A. The measured results were evaluated, graphically processed and compared.
|
|
|
Measurement uncertainty in diagnostics of insulating materials
Kamenická, Zuzana ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with measurement capacity and dissipation factor of capacitor with real dielectric in frequency range 20 Hz to 30 MHz. Liquid and solid dielectrics are measured by LCR instruments and by test fixtures, both from company Agilent. Relative permittivity and loss number are calculated for different instruments settings. The general aim is to specify the influence of parameters as frequency, voltage, integration time and thickness of material on the uncertainties of primary and secondary quantities for measurement.
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