|
|
Design of high voltage source for electrical ageing of insulating mater
Příborský, Václav ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
Target of this thesis is analyse problems of dielectric materials ageing and environment characteristic applied by ageing process. Types of electric stress are comparing in this work, when and how they are working and how to eleminate them. Next aim is design the high voltage sinus transformer as source for measuring of electric stress and ageing dielectric materials. There is discuss about computer control and collecting of the output datas. In the end is source testing by practical measurement of some dielectric samples.
|
|
|
Modelling and behaviour of composite systems in AC electric field
Matoušek, Jiří ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This work deals with modeling of progression of dielectric variables and mixture formulas for solution of properties of composite materials in dependency on frequency. Theoretical part of the work explains physical principles of polarisation mechanisms and influence on dielectric constant with changing temperature and frequency. In theoretical part processes inside the composite material, which is in electrical field are described. The work contains summary of mixture formulas and methods of their derivation. Program for use in education is a part of the work. It allows modelling of progression of dielectric variables in dependency on frequency and Cole-Cole circle diagram. In mixtures it allows modelling of frequency dependencies of dielectric constant in accordance to Maxwell's, Bőttcher's and Lichtenecker's mixture formulas.
|
|
|
Diagnostics of electroinsulating liquids properties
Makówka, Tomasz ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
The diploma thesis deals with the liquid insulators, their properties and their use in the electrical industry. The general aim is to study the physical essence of the dynamic viscosity, the electric conductivity and the diagnostic methods for monitoring these variables. The experimental part contains measuring the dynamic viscosity and the electric conductivity of the mineral transformer oils ESTO BNX, RENOLIN ELTEC and the biodegradable oil MIDEL 7131 during the degradation. The Walden rule is applied on measured results.
|
|
|
Analysis of the properties of liquid crystalline materials
Bodeček, Martin ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
Master´s thesis covers introduction to the problems of materials with specific proprieties named liquid crystals. Theoretic part features primary fission these materials, theirs mechanical, electrotechnical and optical characteristics. Interesting chapter is description choice application including perhaps most interesting using liquid crystals - liquid crystal display. In this trend continues experimental part too, where there are first mentioned characteristics LCD, and after it alone metering capacitive characteristics display with active matrix. Main attention in experiment is however concentraded on evaluation frequency analysis of components complex permittivity regarding in plant temperature on submitted sample liquid crystals.
|
|
| |
|
|
Impact of the climatic conditions upon the varnishes properties
Mikoláš, Jiří ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This bachelor's project analysis influence of moisture absorption on dielectric properties of composite material, which was exposured various relative humidity. The composite material consist of epoxide varnish EPOXYLITE TSA 220S by company Epoxylite Ltd. with various weight percentage number micro-ground mica. This experiment was carried out by dielectric relaxation spectroscopy with frequency range from 100 Hz to 1 MHz. Elementary results of this project are composite material frequency dependencies of component part of complex permittivity.
|
|
|
Mica modified electroinsulating varnishes
Mrkos, Pavel ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This master´s thesis deals with influence of mica content on the electrical properties of electrical insulating varnishes, particularly in the polyester resin Dolphon XL 2102. It focuses on diagnostic methods and testing the properties of electroinsulating varnishes. Examines the potential benefits of micronised mica in order to achieve better electrical insulation properties of the system compared to the matrix. The composite material consists of polyester resin Dolphon XL 2102, which is modified different mass percentage of micronized mica. The results of this project are frequency dependencies of real and imaginary parts of complex permitivity of varnish component.
|
|
|
Synergic effects of multistress ageing of electroinsulating materials
Novák, Lukáš ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
Submitted work deals with monitoring impact of thermal and electric ageing on the dielectric properties of insulating material NKN 0887. In the course of the experiment five sets of dielectric insulating materials were aged. The voltage range has been set from 1,5 kV till 2,2 kV and temperatures were 23 °C and 200 °C. The capacity and loss factor has been directly measured by RLC meter Agilent with attached electrode system. The electrode system operates on the principle of a plate capacitor. The values of relative permittivity and loss number has been calculated from values of capacity and loss factor. For easier confrontation has been frequency dependences of these values plotted in a chart. The Cole-Cole diagrams has been created and factors of Havriliak-Negami function has been calculated. Data has been compared with each other and the effect of ageing factors has been deduced.
|
|
|
Application of nanofiller in electroinsulating materials
Mohyla, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This project deals with calculation parts of complex permittivity varnish samples which is filled by nanoparticles of metal oxides. Opening of this project deals with theory of dielectric and effects in dielectric, theory of compounds and expressions in composite systems. Following topic is theory of nanoparticles and nanotechnologies and summarize adjusted results about this branch of knowledge. In practical part of work is include method which was use to make varnish samples filled by nanoparticles, prepare to measurement methods and whole results of measurement. In the end of work is analysis influence of filler particles each filler types to dielectric material and results verified mixture mathematical expressions.
|
|
| |
guest ::
