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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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Bushing-type current transformer 25 kV, 400/5/5 A
Bálint, Zoltán ; Vávra, Zdeněk (referee) ; Vaněk, Jaromír (advisor)
The aim of this master’s thesis is the design of a double-core bushing-type current transformer. This appliance is intended for measuring and protection of high-voltage distribution systems of the internal type for the highest system voltage of 25 kV. The master’s thesis is divided into four parts. The first part describes the function of the current transformer. The next part deals with the analysis of the phasor diagram and errors of the current transformer. The major part of the thesis deals with the design of the protective and measuring core. The last part describes the 3D model of the bushing-type current transformer.
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Experimental verification of properties of circuit breaker quenching chamber
Kadrnka, Petr ; Vávra, Zdeněk (referee) ; Valenta, Jiří (advisor)
The circuit breakers are able to switch on and off automatically either the short circuit currents up to the limits of their breaking capacity. While the disconnection of the contacts in the switching devices are generated by the arc then it is needed to put it out quickly. A manner of the arcing in the electrical switching devices is influenced by several different factors. It must be taken into account the dynamics of a plasma, a current flowing in the electrodes, a flowing stream in a plasma and a magnetic field generated by a flowing current. This paper is devoted to describe the manner of the arcing in the arc chamber. The experiments carried out in an experimental way attempt to explain, specify and thoroughly comprehend the movements and the characteristics of the arc in a metal arc and in a metal enclosure circuit breaker.
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Idea design of experimental model for LV electric arc properties investigation
Fazekas, Tibor ; Valenta, Jiří (referee) ; Vávra, Zdeněk (advisor)
The aim of the work was a planing of an experimental model for the observation of the low voltage electric arc. The opening part observes the basics of the electric network switching and the electric arc in theory. The next point is definition about the behaviour of the electric arc in the low voltage switching devices, focusing on the movement of the arc along electrodes and in the extinguish chamber. The design of the experimental model, created in Autodesk Inventor 2008, is described in the last part of the work.
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Simulation of phenomena in switchgears
Daševič, Ladislav ; Vávra, Zdeněk (referee) ; Valenta, Jiří (advisor)
Aim of the thesis is to explain the issue of forces acting in circuit breaker caused by magnetic fields induced by short-circuit current. This thesis is focused on force affecting in concrete system of a circuit breaker. The given circuit breaker is made by OEZ Letohrad, the type Modeion BD250. In the thesis the way of creating 3-D model is shown for the purpose of creating numeric simulation by ANSYS 11. The next approach of the thesis is the description of applicating the results for DC and AC current calculations. The noted calculation is made in the programme MATLAB 6.5. The solutions are mentioned at calculations both in the graphic form and numeric specifications. Visualisation was made by using GIF graphic system animation. The individual pictures processing was done in the programme UNLEAD GIF ANIMATOR 5.
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Integration of Environmental Topic in Foreign Language Teaching with Special Focus on German Language
Vávra, Zdeněk ; Nečasová, Pavla (advisor) ; Žofková, Hana (referee) ; Ondráková, Jana (referee)
TITLE: Integration of Environmental Topic in Foreign Language Teaching with Special Focus on German Language AUTHOR: Zdeněk Vávra DEPARTMENT: Charles University in Prague, Faculty of Education, German Studies Department SUPERVISOR: PhDr. Pavla Nečasová, Ph.D. ABSTRACT: The PhD thesis deals with theoretical premises of environmental topic integration in foreign language teaching and relevant tools necessary for the implementation of these premises in teaching practice (teaching aids, teaching methods, psychological aspects). The objective of the thesis is to contribute to further integration of environmental topic in foreign language teaching. Part I and II draw upon available secondary literature, textbook materials, teaching and authentic materials (including those written by the author of the thesis), and other teaching aids (songbooks, parlour games, jigsaw puzzles, pictorial materials, and other objects). Part III (applied research) is concerned with attitudes of selected stakeholder groups towards integration of environmental topic in foreign language teaching, analysis of environmental topic in selected German textbooks, and efficiency assessment of the methodology in relation to foreign language teaching. The methodology of the research is based on questionnaires, exploration methods,...
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Integration of Environmental Topic in Foreign Language Teaching with Special Focus on German Language
Vávra, Zdeněk ; Nečasová, Pavla (advisor) ; Žofková, Hana (referee) ; Ondráková, Jana (referee)
TITLE: Integration of Environmental Topic in Foreign Language Teaching with Special Focus on German Language AUTHOR: Zdeněk Vávra DEPARTMENT: Charles University in Prague, Faculty of Education, German Studies Department SUPERVISOR: PhDr. Pavla Nečasová, Ph.D. ABSTRACT: The PhD thesis deals with theoretical premises of environmental topic integration in foreign language teaching and relevant tools necessary for the implementation of these premises in teaching practice (teaching aids, teaching methods, psychological aspects). The objective of the thesis is to contribute to further integration of environmental topic in foreign language teaching. Part I and II draw upon available secondary literature, textbook materials, teaching and authentic materials (including those written by the author of the thesis), and other teaching aids (songbooks, parlour games, jigsaw puzzles, pictorial materials, and other objects). Part III (applied research) is concerned with attitudes of selected stakeholder groups towards integration of environmental topic in foreign language teaching, analysis of environmental topic in selected German textbooks, and efficiency assessment of the methodology in relation to foreign language teaching. The methodology of the research is based on questionnaires, exploration methods,...
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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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Experimental verification of properties of circuit breaker quenching chamber
Kadrnka, Petr ; Vávra, Zdeněk (referee) ; Valenta, Jiří (advisor)
The circuit breakers are able to switch on and off automatically either the short circuit currents up to the limits of their breaking capacity. While the disconnection of the contacts in the switching devices are generated by the arc then it is needed to put it out quickly. A manner of the arcing in the electrical switching devices is influenced by several different factors. It must be taken into account the dynamics of a plasma, a current flowing in the electrodes, a flowing stream in a plasma and a magnetic field generated by a flowing current. This paper is devoted to describe the manner of the arcing in the arc chamber. The experiments carried out in an experimental way attempt to explain, specify and thoroughly comprehend the movements and the characteristics of the arc in a metal arc and in a metal enclosure circuit breaker.
|
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Idea design of experimental model for LV electric arc properties investigation
Fazekas, Tibor ; Valenta, Jiří (referee) ; Vávra, Zdeněk (advisor)
The aim of the work was a planing of an experimental model for the observation of the low voltage electric arc. The opening part observes the basics of the electric network switching and the electric arc in theory. The next point is definition about the behaviour of the electric arc in the low voltage switching devices, focusing on the movement of the arc along electrodes and in the extinguish chamber. The design of the experimental model, created in Autodesk Inventor 2008, is described in the last part of the work.
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