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Temporally and spatially resolved diagnostics of an electric arc
Holcner, Oldřich ; Šimek, David (referee) ; Kloc, Petr (advisor)
This batchelor thesis "Temporally and spatially resolved diagnostics of an electric arc" deals with the investigation of plasma temperature in an arc formed by evaporation of copper wire. It is an optical method based on determination of temperature from intensity of spectral lines. In this batchelor thesis we explain how spectral lines are formed and how to determine the temperature. In the practical part we process discharge and show the time evolution of temperature at the measured points.
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Software for evaluation of data from CVVOZE laboratory
Petráček, Dominik ; Šimek, David (referee) ; Pikula, Stanislav (advisor)
The diploma thesis is focused on the innovation of partially user-unsuitable software which is used in the CVVOZE short-circuit laboratory for the evaluation of testing of switching and protection devices. The introductory part of the work presents a technical laboratory, which is used for research and development in the field of electrical devices with possibility of testing of short circuits and over-currents. At the first part of thesis, there is made a description of the technical laboratory. The following past is a chapter with basic introduction of tested devices and standard testing conditions of electrical devices in the laboratory. Then following a description of the original evaluation software is made and its shortcomings are pointed out. The practical part is devoted to the creating in LabVIEW, implementation and verification of the functionality of the new evaluation software.
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Analysis of electrodynamic forces in electrcal apparatus
Dobrovolný, Jan ; Valenta, Jiří (referee) ; Šimek, David (advisor)
The master thesis deals with the phenomena called electro-dynamic force in the electrical apparatus. Nowadays, there are high requirements for electrical devices. The devices and especially their contacts are subject to high demands on reliability, reliability and mechanical durability. The electro-dynamic forces caused by the passage of electric current mechanically deform the current path. The design of the electrical apparatus must take these forces into account. Equations for electro-dynamic forces calculation are presented. In master thesis, individual parts of the current path are derived and described. Various configurations and designs of the current path are solved. The thesis also deals with the issue of forces in electrical contacts. Individual theoretical equations are then applied to a particular disconnector QAK, made by company IVEP, a.s. Parts of the disconnector were redrawn into 3D program SolidWorks. The model was analysed in program ANSYS Maxwell. The thesis compares the achieved results of analytical equations and numerical simulations.
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Diagnostics of medium voltage and high voltage circuit breakers
Kapalla, Alexej ; Šimek, David (referee) ; Dostál, Lukáš (advisor)
This bachelor work is focused on medium-voltage and high-voltage circuit breakers and their diagnostics. The thesis presents the history of HV circuit breakers and their main division. Subsequently, the relevant standards are listed in the work and diagnostics of the MV circuit breaker VD4 and the HV circuit breaker S1-245 from AEG is performed. In case of the VD4 circuit breaker, a new and used circuit breaker was diagnosed. The measured values are then compared and the impact of usage is shown. The work describes the measurement of main contact resistance, insulation resistance, closing and opening times and vacuum quality.
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Investigation of the durability of low voltage switching apparatuses construction parts
Dalecký, Jan ; Dostál, Lukáš (referee) ; Šimek, David (advisor)
This thesis deals with study of durability of low voltage switching devices components. It describes components of circuit breaker and low voltage contactor and contains function models of these devices in various states. Based on model analysis, components that can get worn, damaged or destroyed were selected. Further practical experiments on two samples of circuit breakers from different manufacturers were executed to verify their technical parameters and parts durability. Failure of some components can cause switching device to malfunction.
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Development of DC arc quenching chamber
Černohorský, Petr ; Valenta, Jiří (referee) ; Šimek, David (advisor)
Seminar thesis focuses on the issues about quenching the electric direct arc by the quanching system. Teoretical part deals with action about quanching the direct arc and with another actions which happens in direc discharge. There is described proposal and construction of the insulating quenching system. Than chamber was testing in high voltage laboratory and the results from testing was evaluated.
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Diagnostics of medium voltage and high voltage circuit breakers
Kapalla, Alexej ; Šimek, David (referee) ; Dostál, Lukáš (advisor)
This semestral work is about high voltage switchgears and their diagnosis. In this work there is part about history of HV switchgears and their dividing. Next part of this work describes diagnostic of HV switchgears VD4 24 ABB and AEG S1-245. In case of HV breaker VD4 there was provided diagnostics of new VD4 and used VD4. The measured values are then compared in the work and the influence of usage of breaker is presented according to his parameters. This work describes measurment of resistance of main contacts, insulation states.
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Spectroscopic analysis of an electric arc
Hartman, Tadeáš ; Kloc, Petr (referee) ; Šimek, David (advisor)
The bachelor thesis deals with spectroscopic diagnostics of electric arcs. The first part explains the creation and properties of electric discharges, especially electric arcs. Methods for composition and temperature analysis of electric arcs are also given there. The next part deals with practical use of these methods for identification of elements contained in electrodes between which an arc discharge was happening, measurement of the arc temperature and also measurement of the temperature of the electrodes. In the last part, these methods are also used for the analysis of time progression of composition and temperature of an electric arc created on a contactor's contacts with the resistive load.
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Diagnostics of current path of high-current apparatuses
Váša, Lukáš ; Bušov, Bohuslav (referee) ; Šimek, David (advisor)
Bachelor’s thesis is focused on the theoretical analysis of methods of technical diagnostics with focus on high-current devices. An overview of the methods used in technical practice is elaborated. In addition, the thesis deals with the strain of current carrying path, subsequently the work focuses on the thermal stress of parts of the current carrying path and its temperature rise. Methods of diagnostics by measuring transient resistance and methods of measurement of temperatures are described and each of the methods’ advantages and disadvantages are stated. The practical part is focused on the diagnotics of the switch disconnector and the disconnector by measurement of the transient resistances of all contacts of the current carrying paths and the following measurement and evaluation of temperature rise of the components by thermal imaging camera. Adjustments to the disconnector leading to financial savings are suggested on basis of these measurements.
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Experimental Measurements Of High Temperature
Objects In Contact With An Electric Arc
Šimek, David
The paper is focused on the measurements of high temperatures related to electric low voltage apparatuses switching off process. An optical emission spectroscopy was used for these measurements, because the optical emission spectroscopy is one of best methods for obtaining a temperature of high temperature objects. Experimental measurement of radiation spectra of electrodes among which an arc was burning is presented. Electrodes was made of carbon with stabilisation core with potassium and sodium admixture. Radiation spectrum of electrodes was close to the black body radiation spectrum. The problems connected with the measurements are discussed. The main part of the paper deals with a calculation of the electrode temperature using Planck function.
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