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Steady-state operation of 110 kV power line
Pastorek, Jaroslav ; Bok, Jaromír (referee) ; Blažek, Vladimír (advisor)
This Bachelor's thesis addresses the steady operation of 110 kV power lines. It is well known that these lines are used within the distribution system of very high voltage levels and are used to transfer large amounts of energy over long distances. The essential prerequisite for the transfer of such an amount of energy is to achieve the greatest efficiency possible. Therefore, there are methods developed, by which under known circumstances on one end of the line we can calculate the line ratios at the other end. These methods can be classified into exact, approximate and graphic methods. With approximate methods, T – element and ? – element, the most popular ones, are used. Only a brief description of the graphic method is given. Before the calculations of these methods, a procedure for determining various parameters of the external line is described. In the practical part, calculations based on the given example are listed. The example addresses calculation of ratios at the start of the line and ratios during short-circuit and freewheeling operation. The end contains a brief summary and comparison of the results. 100 kV lines can be either designed either as buried cables or external lines hanging from pylons. Buried cables are rarely used for 100 kV, so this Bachelor's thesis is focused on external lines.
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New solutions of converters for measurement of current-mode filters
Štork, Petr ; Kubánek, David (referee) ; Jeřábek, Jan (advisor)
This bachelor’s thesis describes some new solutions of differential converters that convert voltage to current and vice versa. Such converters are necessary for measurement of frequency filters in a current mode due to absence of instruments able to mesure signals with current as signal carrier. The goal is to design such converters that should influence gauged frequency properties in a current mode as little as possible. Converters will consist of operative amplifiers with current feedback. Converters designed this way are tested using simulations from PSpice programme, where particularly wideness of band of individual solutions is tested. Simulated solutions that are the most suitable ones are practicably re-enacted and gauged. These resuls of measurement and simulations are compared.
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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.
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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.
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Application possibilities of LNVGA programmable amplifier
Sobotka, Josef ; Hanák, Pavel (referee) ; Jeřábek, Jan (advisor)
This thesis deals with the theoretical description of the qualitative characteristics and parameters of some modern active elements, also discusses the theory of signal flow graphs at the level applicable for the following frequency filter design methods. The thesis is also generally discussed the issue with the circuit simulator PSpice modeling theory and voltage amplifiers on the basic 6-levels. The practical part of the work is divided into two parts. The first practical part is dedicated to design four levels of simulation model of components LNVGA element. The second practical part contains detailed theoretical proposals for three circuit structures implementing the frequency filters 2nd order (based on the basic structure of the OTA-C) using signal flow graphs with configuration options of Q and fm based on the parameters of active elements in the peripheral structure and their verification with prepared LNVGA model layers.
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Three-phase sinusoidal pulse width modulation algorithms
Rudolf, Ladislav ; Červinka, Dalibor (referee) ; Klíma, Bohumil (advisor)
The main theme of this bachelors‘s thesis is to introduce readers into the algorithm of generating three-phase sinusoidal pulse width modulation. Main attention is concentrating to methods of generating Pulse width modulation method such as comparate PWM modulation technique and space modulation of voltage vector SVM. The functional units of algorithms are analysed and described from the basics. In addition, this project describes the basic analog solutions and even the implementation of the PWM modulator into signal processors DSP56F800.
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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.
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Apparatus for parameter identification instrument voltage transformer
Tománek, Drahomír ; Valenta, Jiří (referee) ; Dohnal, Petr (advisor)
This master thesis describes the design and production of devices for identifying the parameters of the instrument transformer. Work is divided into seven chapters. The first part focuses on the production of instrument voltage transformer. The next section describes the measurement and description of the parameters of instrument voltage transformer and design of printed circuit boards. Another section is devoted to a program for measuring card. The final part is manufactured and tested unit conducted the first test measurements.
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Frequency-to-Voltage Converter
Šindelář, Michal ; Bejček, Ludvík (referee) ; Beneš, Petr (advisor)
This bachelor’s thesis deals with the issue of the transfer frequency to voltage focusing on dynamics and accuracy. The goal of this thesis is the design and implementation of the converter based on the input arguments. The graph evaluates the tradeoff between dynamics and accuracy. It is possible to choose a more suitable solution to transfer frequency to voltage for the specified requirements.
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Band Gap - accurate voltage reference
Bubla, Jiří ; Petržela, Jiří (referee) ; Kolka, Zdeněk (advisor)
This diploma thesis is specialized on a design of a high accuracy voltage reference Bandgap. A very low temperature coefficient and output voltage approx. 1,205V are the main features of this circuit. The paper contains a derivation of the Bandgap principle, examples of realizations of the circuits and methods of compensation temperature dependence and manufacture process, design of Brokaw and Gilbert reference, design of a testchip and measurement results.
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