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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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Design of MV contactor for railway application
Pala, Lukáš ; Šimek, David (referee) ; Valenta, Jiří (advisor)
In the introduction a traction circuit is analyzed with different types of electric devices. The thesis describes power railway electric circuits, their loads and types of used contactors. Railway standards chapter summarizes requirements of standards for railway contactors. Follows literature focusing on power current switching and power switching devices design. Based on previous, a design procedure is developed for railway MV contactor in accordance with end-user and standards requirements. Thesis closes with pre-designing a railway contactor by calculating electrodynamic forces, heatflow and mechanical components.
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Design of a 25 kV traction disconnector
Buchta, Martin ; Bušov, Bohuslav (referee) ; Šimek, David (advisor)
This diploma thesis deals with the design of a traction disconnector for 25 kV AC and a rated current of 800 A. The result should be a competitive disconnector that is capable of potential applications on domestic railways and should have parameters that other local manufacturers do not currently offer. This is, for example, electrical strength or the size of the rated current, which is an economic option for most railway lines in the Czech Republic. According to the proposed drawing documentation, the disconnector was assembled and then the selected disconnector parameters were tested. For example, electrical strength tests, short-circuit tests, constant current tests, etc. were performed. The calculated and measured values were compared together. The designed disconnector was financially and technically evaluated on the basis of test results and the construction itself. Finally, some appropriate adjustments were proposed.
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Electrodynamic forces in electrical apparatuses
Dobrovolný, Jan ; Bušov, Bohuslav (referee) ; Šimek, David (advisor)
The bachelor's thesis deals with phenomena caused by electrical current passing through electrical apparatuses current path. The main focus is on electrodynamic forces. These forces are created by the interaction of magnetic fields and significantly takes effect in case of short circuits because they rise with square of current. Electrodynamic forces are problematic especially in contacts, where it causes a repulsive force working against the contact force. A proposal of electrical apparatus must take into account these forces and must be sufficiently dimensioned. Selected apparatus - disconnector, is redrawn into 3D program SolidWorks. Electrodynamic forces on individual parts of current carrying path were calculated for short circuit current. Total balance of forces is created. The disconnector has been tested for a withstand current to verify an endurance against electrodynamic forces.
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Design of earthing switch for diconnecter of generator
Petrič, Peter ; Šimek, David (referee) ; Bušov, Bohuslav (advisor)
This master thesis is focused on the design of earthing switch for the indoor three pole generator disconnector from IVEP, a.s. The main task of the theoretical part of the master thesis was mechanical and electrical calculations on the contact system and the design of two variants of earthing switch construction. It has been proposed two variants of earthing switch construction. The first variant included three earthing knives for each pole of earthing switch and the other variant included two earthing knives for each pole. The aim of the practical part of this diploma thesis was to create a model of the earthing switch for generator disconnector, to simulate the heating of the contact system by passing the short-circuit current and to prepare the production documentation. For modeling, calculations and simulations were used Autodesk Inventor 2018, Matlab and Ansys Workbench.
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Calculation of electrodynamic forces in 1600 A circuit breaker
Musil, Pavel ; Bušov, Bohuslav (referee) ; Valenta, Jiří (advisor)
The thesis is focused on the calculation of electrodynamic forces that counterwork on moving contacts of compact circuit breaker BL1600 from the company OEZ Letohrad. The thesis is divided into separates chapters that build on themselves. In the introduction the reason why we deal with calculation of dynamic forces and structural arrangement of current carrying path is described. In the following chapter there is a theoretical analysis of electrodynamic forces that conterwork on individual parts of circuit breaker´s element. The third part is devoted to structural arrangement of the circuit breaker BL1600. In this part we can find an example of using the circuit broker Modeion in practice. Two next chaptures deal with adjustment of the model of current carrying path which then serves for the calculation of electrodynamic forces. The rest of the thesis is devoted to my own calculations. These calculations are mainly stationary where we try to find the forces that conterwork on the contacts in a steady current and in a point in time. There are also dynamics calculation when we can watch the forces that counterwork on contacts in a certain time interval. The last chapter is devoted to a stationary calculation of forces that counterwork on the electrical arc which arises while turning the short-circuit current off. The obtained results are evaluated in partial conclusions of this thesis.
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Study of arc root movement in a model of the LV quenching system
Fendrych, Martin ; Aubrecht, Vladimír (referee) ; Valenta, Jiří (advisor)
Thesis focuses on the basic characteristics of plasma, problems about origin of electrode spots and electrodynamics force acts on the electric arc. In the practical part was realized and produced model of a LV quenching system. Using optical diagnostics was received necessary data to analyze the movement of the electrode spots. The movements of the electrode spots were analyzed in terms of value RMS current passing through the electric arc, value of absolute pressure model in the LV quenching system and distance from each electrode.
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Dimensioning of current-currying way of electrical apparatuses
Šic, Pavel ; Dostál, Lukáš (referee) ; Bušov, Bohuslav (advisor)
Bachelor‘s thesis is focuses on the issue of designing electrical switching devices, especially dimensioning of the current-carrying paths according to the effects of electrodynamic forces. There are dimensioning requirements for current carrying paths of switching devices in the introductory chapter. Fundamental requirements are: sufficient dielectric strength between parts at different potential, resistance to thermal effects of electric current and current path arrangement considering electrodynamic forces. Typical current path arrangements of electrical apparatuses are justified in second chapter. Furthermore, the actual problems to solve are formulated, corresponding with the development of technical solutions. Emphasis is laid upon proper description of modifications of the proposal so to limit their negative impact of secondary phenomena such as electrodynamic forces or thermal effects. The best solutions then directly positively use these phenomena. The present progressive technical solutions retrieved in a patented state of the art using Goldfire Innovator software are described in the third chapter. The work is then focused on rotary contact arrangement patents from the very first, through the pioneering patent to the present. Hereinafter are described the features of the evolution of technology development – micro and macrosegmentation. In the last chapter, there are analytically calculated electrodynamic forces acting on the contact arm of low voltage circuit breaker in both open and closed state and medium voltage disconnector. Both technical solutions are evaluated due to given requirements.
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Calculation of electrodynamic forces in 630 A circuit breaker
Staněk, Pavel ; Bušov, Bohuslav (referee) ; Valenta, Jiří (advisor)
The aim of this thesis is to simulate the action of electrodynamic forces on current carrying path and a movable contact of the circuit breaker OEZ Modeion BH 630NE. For the calculation there is used the simulation program Ansys Maxwell. The first part is devoted to theoretical analysis of electromagnetic forces on a conductor in a magnetic field. Further I discuss the constructional design of the circuit breaker itself, especially the current path and the contact mechanism. In the next part there is (with using program Autodesk Inventor) created a simplified 3D model of the current path including an arc chamber. With program Ansys Maxwell then there is performed simulation of the acting of forces in each mode. This is magnetostatic and transient analysis for symmetrical and asymmetrical flow of the fault current. In conclusion the results obtained are evaluated and processed in the tabular way.
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Design of earthing switch for diconnecter of generator
Petrič, Peter ; Šimek, David (referee) ; Bušov, Bohuslav (advisor)
This master thesis is focused on the design of earthing switch for the indoor three pole generator disconnector from IVEP, a.s. The main task of the theoretical part of the master thesis was mechanical and electrical calculations on the contact system and the design of two variants of earthing switch construction. It has been proposed two variants of earthing switch construction. The first variant included three earthing knives for each pole of earthing switch and the other variant included two earthing knives for each pole. The aim of the practical part of this diploma thesis was to create a model of the earthing switch for generator disconnector, to simulate the heating of the contact system by passing the short-circuit current and to prepare the production documentation. For modeling, calculations and simulations were used Autodesk Inventor 2018, Matlab and Ansys Workbench.
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