|
|
Stabilized operation of the 220 kV power line
Staněk, Pavel ; Ptáček, Michal (referee) ; Blažek, Vladimír (advisor)
This thesis deals with methods of solving lines under voltage levels of very high transmission voltage and extra high voltage. The first, theoretical part of this paper analyses different methods how such lines are solved. In particular, an accurate solution is provided simulated by means of a line with evenly distributed parameters, and an approximate solution simulated by means of a line with lumped parameters. Furthermore, special cases of steady running conditions of the line are reviewed, such as no-load running, short-circuit and line operation with natural load. In conclusion of the theoretical part is given a general method of solving an extra-high-tension and extra high voltage network; also, some graphical methods of solving such networks are shown including their brief description. The second, practical part of the present paper involves application of the above mentioned methods of solution on a specific line with given parameters, solving conditions at the power line under steady running conditions and in special cases of the line operation. The conclusion of the thesis summarizes the obtained results.
|
|
|
Design and realization of V/I and I/V symmetrical converters
Chrást, Jakub ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
Master´s thesis deals about design of symmetrical converters voltage on current and current on voltage. These converters will be used for measuring frequency characteristics of differential frequency filters. Current feedback amplifier was used as active element. Some circuits useful for this function were chosen. Various integrated circuits were put into these circuits. All variations were simulated in computer program Orcad. In terms of computer simulations the best variation was chosen. Selected variants were practically verified and control measuring were realized.
|
|
|
Assessment and evaluation of safety in power. machines
Hromek, Lukáš ; Janda, Marcel (referee) ; Veselka, František (advisor)
This thesis is focused on the security and improving of electrical rotating machines service life, especially asynchronous motors. Work includes a description of the most common disorders, short description of the asynchronous motor cage casting, analysis of provided decommissioned motors with photo documentation. The last part of this thesis is focused to vibrodiagnostic of asynchronous motor with simulated imbalance and motor emplacement by laser.
|
|
|
Analysis of methods of measurement of fully-differential frequency filters
Kučera, Tomáš ; Kubánek, David (referee) ; Jeřábek, Jan (advisor)
This bachelor thesis focuses on measurements methods of differential frequency -selection filters with active elements in current mode. Firstly it describes differential frequency-selection filters in current mode and conversions from voltage to current mode. Next the thesis deals with measuring of particular voltage converters to differential current and back from differential current to voltage, which is an integral part for measurements of differential frequency-selection filters in current mode. For design of particular converters there was used program OrCAD there and subsequent simulation was executed in program PSpice.
|
|
|
Tissue impedance measurement
Nejezchleba, Zdeněk ; Rampl, Ivan (referee) ; Chmelař, Milan (advisor)
Bachelor thesis deals with the measurement of resistance of the skin with direct current. It describes the changes in the value of time, depending on the emotional stability of the human and his psychological habit. It is a method able describe the relatively objectively and compare human emotions.
|
|
|
Calculation of heat and force field UniGear ZS1
Mokrý, Lukáš ; ABB, Drahomír Tůma, (referee) ; Dohnal, Petr (advisor)
The aim of my work is to describe high-voltage switchgear type UniGear 500R, which is part of UniGear switchgears family. I will focus on heating issue of one 500R unit and its parts during operation. Maximum values of this heating is limited by standards and can´t be exceed to ensure safe and reliable operation. That is why the heating tests are necessary part of designing and developing switchgears. Calculation will be made by two different ways. First is classic one-pole heating net method and second is numerical simulation in Solidworks flow simulation program. Except the theoretical description there will be presented also used 3D model and explanation of both method, used to calculation and simulation. Last point of this work is measuring of this type of switchgear and getting real data. The main point there is to compare measured values with values calculated and decide if is possible to simulate tests with appropriate accuracy. Then would be also possible to substitute the real test in laboratory, which costs many thousand crowns and takes lots hours of time. This work is collaborated with EJF division of ABB Company, where I am employed. Heating issues in this company is always on process, because of developing and improving of their products. So this work could be helpful in this field. ABB provides all materials needed, especially technical catalogues, 3D model and final values from laboratory measuring. Support from college faculty is mainly in study consultations and proposing of calculations making. In the end of work will be make final comparison and evaluation of achieved results.
|
|
|
Stabilized operation of a 400 kV power line
Girga, Eduard ; Špaček, Jaroslav (referee) ; Blažek, Vladimír (advisor)
Electrical wiring 400 kV is the most used transfer wiring in the Czech Republic with length over three thousand kilometers. It is frequently used for running out significant output from the big power plants and for its significance in electrical engineering. Theoretical part of this thesis deals with the cross-section of mainly used methods for high and extra high stable wiring voltage solution. These methods can be generally dividend into precise and rough. Both of these methods will be analyzed in next chapters. Exact solution comes out from the presumption of equally spaced parameters. The rough solution uses substitution of double gates wiring, this method is accurate enough and accelerates the calculation. Former mentioned reasons explains it’s often use in technical practice. The electric line is substituted by T-cell, II-cell or Steinmetz cell according to length and required precision. Special method of rough solution is the broad method which enables to solve randomly knotted network by using II-cell to replace electric wiring between single knots. This method is mentioned in thesis for completeness; the network solved by me is not knotted. Part of the theoretical thesis is the analysis of specific transfer cases. In computing part will be mentioned not only the computation of stable wiring state with precise an rough method - with all former mentioned cell but the computation of specific transfer cases as well. In the end will be concluded all the counts from computing part and from precision view evaluated used methods of the stable wiring solution.
|
|
|
Risks and Impacts of Black-out in Czech Republic
Tomášková, Kateřina ; Poláčik, Ján (referee) ; Lisý, Martin (advisor)
Electricity is an integral part of our daily life. Only a small problem in the power system and a small current outflow can cause us a lot of inconvenience, let alone a wider outflow of elektricity. The aim of this thesis is to define the risks of black-out for the Czech republic. Then perform resers of foreign experience with the black-out and on the base of these experiances, outline the possible impacts for the Czech republic, in case that this situation would occur once in our country.
|
|
|
PDF Text Extraction
Kubík, Petr ; Otrusina, Lubomír (referee) ; Schmidt, Marek (advisor)
Bachelor's thesis is concerned with text extraction from PDF dokument which contains mainly multi-column text. There's a description of PDF structure and analysis of text extraction from PDF document. Thesis is focused on suggestion of algorithm's implementation of improving text extraction.
|
|
| |
guest ::
