National Repository of Grey Literature 109 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Short Circuit Currents in the Sokolnice 400 kV Switching Station with Direct 400/110 kV Transformation Applied
Vojtěch, Pavel ; Špaček, Jaroslav (referee) ; Blažek, Vladimír (advisor)
The destination of this Bachelor´s Thesis is to explore short circuit currents for voltage level 400 kV in the switching station Sokolnice before year 1995 and after this year, when came to installation of the convertor T402 and to voltage direct 400/110 kV transformation applied. The Thesis is detecting at relation as for three-phase short circuit do for single-phase short circuits, for 400/220/110 kV primary transformation variation in voltage and for variation 400/110 kV, the change which came after connection of the convertor T402. In base of this calculation will be explored the short circuit resistance rating switching station in agreement with parameters ordered by the comp. Inc. ČEZ Prague.
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.
Dynamic electroneurostimulation and electrical properties of skin
Špeta, Marek ; Dvořák, Petr (referee) ; Špinka, Jiří (advisor)
The focus of this diploma thesis is on theoretical basics of dynamic electroneurostimulation, which is an effect of electrical signal on acupuncture points of skin. This technology is used in devices made by russian DiaDENS company. Practical part of this thesis covers design of human skin impedance model. Especially derivation from three-element Cole-Cole model. Elementary, there is design of equivalent circuit of constant phase element and its incorporation into circuit. Then this circuit is designed, simulated and produced. Resulting product is used as a load to measure the characteristics of the DiaDENS device.
Load Flow Calculation and Design of Distance Protection Relay Settings of 110 kV Overhead Line
Jasenský, Filip ; Vaculík, Petr (referee) ; Toman, Petr (advisor)
Bachelor thesis load flow calculation and design of distance protection relay settings of 110 kV overhead line acquaints with the theory calculation of steady operation, short-circuit conditions and a proposal setting the distance protection. The theoretical part is made an example of a simple calculation to show leadership methods of calculation. The practical part is a calculation of steady operation and short-circuit conditions. Short-circuit ratios are calculated for a single operation and parallel operation of transformers in Otrokovice. Calculated using the initial shock symmetrical output from the calculation of short-circuit conditions is verified by short circuit resistance of substations. The practical section setting the distance protection ABB REL 316*4 and compensation earth faults. Calculation of steady state and short-circuit conditions designed basic operational state of the network, for which the design of a distance protection relay settings.
Analysis of liquid electrolyte electrical parameters using impedance spectroscopy
Brabenec, Josef ; Pikula, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The bachelor thesis deals with impedance spectroscopy of electrochemical systems, especially liquid electrolytes. The method of impedance spectroscopy is widely used to describe electrochemical cells, batteries and electrolytes for diagnostic purposes over a wide range of frequencies. This thesis presents the main types of impedance imaging in the complex and frequency domain, as well as basic information on the measurement methods used and the methods for impedance analysis. The main part of the thesis was the development of software for automated impedance measurements and estimation of equivalent circuit parameters using basic and specialized circuit elements. A workplace with fabricated electrodes for liquid electrolyte measurements was prepared for the application. The functionality of the application was verified by real measurements of different concentrations of water and salt solutions. The validity of the estimated equivalent circuit parameters was verified on measured simple circuits connected from basic circuit elements and was also verified using the commercially used ZView software.
Automatic antenna analyser
Dufek, Ivo ; Šebesta, Jan (referee) ; Lukeš, Zbyněk (advisor)
This project is dealing with methods of measuring impedances of the antenna systems in the frequency range from the low frequencies to the very high frequencies. There is a discussion about different methods of measuring impedance and each technique is critically evaluated. In terms of this project is compared few types of the professional antenna analyzers. According to this comparison there was made the concept of my own antenna analyzer. There is a detailed description of the design of this device’s important parts including software equipment. Designed instrument has been built and tested.
Impedance Spectroscope
Sliž, Jiří ; Pikula, Stanislav (referee) ; Beneš, Petr (advisor)
The aim of this thesis is to design a measuring instrument intended for impedance spectroscopy. There are definitions of the terms impedance and impedance spectroscopy and methods of its measurement. The integrated circuit AD5933 from Analog Devices was used for measurement. The measuring device is controlled by a microcontroller PIC32MX460F512L, which communicates with the measuring circuit, controls the actual measurement and communication with the control PC via the USB interface. The work also includes the creation of the control program, which ensures calibration, measurement, storage data, and data visualization. Device has also the possibility of repeated measurements and automatic switching of multiple inputs. Finally, the proposed device has been tested on two microbiological experiments. Impedance change depending on the concentration of bacteria in the measured solution was proved in first experiment. The aim of the second experiment is to distinguish bacterial strains of Staphylococcus epidermidis which creates biofilm and which not. With PLS was created validation model that can be used as a detector strains forming biofilm.
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.
CVVOZE Short circuit lab description
Brdečko, Aleš ; Valenta, Jiří (referee) ; Dohnal, Petr (advisor)
This diploma thesis deals with the analysis and description of high power laboratory CVVOZE. In the text we can find a description of the individual elements high power laboratory stating their parameters and their analysis from the perspective of impedance. The practical concern of this work is the creation of program for calculating the adjustment burdens and creating utilities helpful for operation and interpretation of laboratory function laity and technical employees.
Calculation of short circuit currents in electtrical network
Reiter, Martin ; Vaculík, Petr (referee) ; Toman, Petr (advisor)
First chapters of my bachelor´s thesis are focused on failures of networks, simple characteristics and description of their potential danger. Next chapters are thoroughly focused on the short-circuit, on the short-circuits graphs, on the circumstances which caused them and on their calculation. Next part is about the example, which is counted by the IEC 60909. First example is simple network. Second example is real distribution network 110kV. We are going to cogitate two involves for the real network and we are going to calculate symmetrical and asymmetrical short circuit current. There is summary of knowledge about the short-circuits and evaluation of the real distribution network at the end of my thesis.

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