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Design of HV disconnector
Hrubý, Radek ; Valenta, Jiří (referee) ; Vávra, Zdeněk (advisor)
The text focuses on the design of high-voltage disconnector. It made a brief theoretical analysis of construction equipment directives. Proposal follows the insulation system apparatus according to empirical formulas. Hereafter, we discuss the design of current track isolators. For the flow path are calculated electrodynamic forces acting. Warming current path is simulated by a computer program ANSYS, this simulation includes 3D device model and determine the material and thermal constants. Finally it is shown calculating the required torque on the shaft of the disconnector. This calculation is simplified. The output is a 3D sketch of the device model used to simulate warming.
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Parameters identification of the asynchronous machine substituting circuit
Běloušek, Radim ; Cipín, Radoslav (referee) ; Patočka, Miroslav (advisor)
Mathematical model and substituting circuit both include several parameters, which is important to determine for a control. This work is target on identification of parameters of substitute circuit of the asynchronous machine in -network form. The work is divided into several main units. In the first of them are shown the methods of identification of asynchronous machine on the selected machine. The measuring of torque characteristic by classical way with dynamometer and by dynamically with fly-wheels is shown in the next part of this work. The final part of this work is devoted to interpretation and comparison of achieved results.
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Program for calculation of ventilation and heating in synchronous machine
Kolář, Pavel ; Ondrůšek, Čestmír (referee) ; Huzlík, Rostislav (advisor)
This master´s thesis deals with ventilation of synchronous generators with a cylindrical rotor. For the design of ventilation we apply basic physical laws in the field of hydromechanics and thermomechanics. Therefore the first chapters are devoted to these subjects. They are followed by the description of ventilation systems and a thermal net is created and solved for one of them consisting of the thermal resistance and sources. The final part deals with a program, which I developed in Visual Basic 2008 Express Edition. This program enables to calculate the ventilation and heating of individual parts of the machine after entering basic machine dimensions and losses.
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USING MODERN NUMERIC METHODS IN DESIGN OF LOW VOLTAGE CIRCUIT BREAKERS
Dostál, Lukáš ; Hüttner, Ľudovít (referee) ; Petráček, Miloš (referee) ; Aubrecht, Vladimír (advisor)
The theses is focused on efficient use of numerical methods in development of low-voltage switching devices, namely to create a physically correct and reliable numerical model of the temperature field to find an application in the design of the current path of a device for various operating conditions. The creation of this numerical model requires not only correct inclusion of all modes of heat transfer - conduction, convection and radiation, but also correct solution of problematic transient resistance - both electrical and thermal in electrical contacts at different stages of usage. Therefore an essential part of the theses forms a thorough experimental analysis of the necessary material properties and dependencies which forms input data for the numerical model that is based on the finite volume method. The last part of the theses deals with debugging and verification of numerical model to correspond with experimentally obtained data. The result of the theses is the numerical model which is able to solve correctly both steady and various transient states of swiching devices.
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Computation of thermal network of switchgear type UniGear and comparison with the real temperature rise test
Rybka, Michal ; Tůma, Drahomír (referee) ; Orságová, Jaroslava (advisor)
The Master’s thesis deals with thermal network computation of UniGear type switchgear and it compares the calculated results with the real temperature rise test. The thesis describes both electrical and non-electrical characteristics of such a switchgear as well as its application in variol fields of industry. Description of switchgear auxiliary equipment is obvious part of the thesis. Modelling of current carrying track in software environment of Autodesk Inventor and preparing of this current carrying track for thermal network calculation in software environment of ANSYS follows. Main part of this thesis is presentation of thermal analysis results and their comparison with the real temperature rise test.
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Comparison of the temperature-rise test of low voltage circuit breaker at different operating settings
Kusák, David ; Ing. Kamil Mikyska (OEZ s.r.o.) (referee) ; Dostál, Lukáš (advisor)
The bachelor thesis deals with the evaluation and comparison of the measured values of terminal temperatures of two molded case circuit breakers of the 3VA1 series in different operating settings. temperature rise test is carried out when the device is loaded with rated current and is used to verify whether some parts of the device do not exceed the permissible warm-up value according to the relevant standard. The theoretical part of the thesis focuses on the design, principle of operation and operating states of modular and molded case circuit breakers. Furthermore, a general description of the test conditions of the temperature rise test is presented. In the practical part of this work, 45 temperature rise testand calculation of the power loss of circuit breakers were carried out. breaker series 3VA12
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USING MODERN NUMERIC METHODS IN DESIGN OF LOW VOLTAGE CIRCUIT BREAKERS
Dostál, Lukáš ; Hüttner, Ľudovít (referee) ; Petráček, Miloš (referee) ; Aubrecht, Vladimír (advisor)
The theses is focused on efficient use of numerical methods in development of low-voltage switching devices, namely to create a physically correct and reliable numerical model of the temperature field to find an application in the design of the current path of a device for various operating conditions. The creation of this numerical model requires not only correct inclusion of all modes of heat transfer - conduction, convection and radiation, but also correct solution of problematic transient resistance - both electrical and thermal in electrical contacts at different stages of usage. Therefore an essential part of the theses forms a thorough experimental analysis of the necessary material properties and dependencies which forms input data for the numerical model that is based on the finite volume method. The last part of the theses deals with debugging and verification of numerical model to correspond with experimentally obtained data. The result of the theses is the numerical model which is able to solve correctly both steady and various transient states of swiching devices.
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