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An effect of natural phenomena on electrical devices
Müller, Michal ; Aubrecht, Vladimír (referee) ; Bušov, Bohuslav (advisor)
The Thesis deals with the impact of natural effects on electrical equipment. It describes the various natural effects and shows how it impacts, what it impacts on and what the source of its impact is. The main point of this Thesis is the issue of atmospheric charge (storm and lightning) and the issue of coronal mass ejection (CME). The Thesis shows causally consequences string of geomagnetical field disturbances and resultant power system impacts. There are mentioned historic storm events and power system impacts and description of events in Hydro-Quebec – the most important event. Of this species. At the end there are shows possible way of mitigation power system impacts.
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MV netwok design for 75 new houses in Damborice
Makuta, Peter ; Novák, Vojtěch (referee) ; Ptáček, Michal (advisor)
Content of this thesis is medium voltage network design for seventy five houses in Damborice. At the beginning author discuss about history of transmission network and distribution network. Next topic is about steady state of network. In theoretic part are different solving methods of linear and non-linear simultaneous equations discussed. Author describes four methods – method of node voltages, elimination of balance node, Gauss-Seidel and Newton method. The electric properties of both the overhead transmission lines and cable lines and their variety are part of this work too. There is purpose, forms and parameters of transformers described. Simplicity of author’s design should reduce the usage of many electrical elements visible to residents.
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Power Converter for the electric DC arc welding
Vranák, Daniel ; Vorel, Pavel (referee) ; Patočka, Miroslav (advisor)
The main aim of thesis was produce a draft power converters for DC arc welding, which would be suitable for use in regular service. For the purpose of the proposal, first must be acquainted with the possible methods used converters whose distribution and explain the principle place in beginning thesis. Next it was transferred detailed design of individual components, which was used for the construction of the power part of the welder.
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Hybrid Microphone Preamplifier
Valach, Ondřej ; Hanák, Pavel (referee) ; Koton, Jaroslav (advisor)
The diploma thesis deals with the design of hybrid microphone preamplifier with stepless choice of amplification technology between active part using tube or semiconductor elements. Before the design, the basic physical relations of electroacoustics were described. Problems of connection of audio devices, their voltage and noise conditions. At last technical properties of microphones and tubes were described. In the practical part, the overall structure of the hybrid preamplifier is designed and the goals of the thesis are set. This is followed by a detailed design of the preamplifiers. From input circuits through individual amplifier stages of the semiconductor and tube sections to the output of the device. Much of the circuit was tested by software simulations. Based on the results obtained in the design of the signal part of the preamplifier, the power circuits were designed. Finaly the preamplifier functionality was verified by measurement on the Audio Analyzer.
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Simulink transformer models based on equivalent circuits
Petrič, Peter ; Huták, Petr (referee) ; Pazdera, Ivo (advisor)
The aim of the bachelor‘s thesis is to project and then realize models of transformer in Matlab/Simulink program. These proposed procedures show the relation between original transformer and its spare connections. The first part of bachelor‘s thesis is oriented to theory of transformers which defines basic parametres and relations between them in transformer. Later in this part we try to describe cross-over from basic transformer model to the spare connection which is needed in realization of model in Simulink. The second part of bachelor‘;s thesis is oriented to theoretical description of vector transformation. It describes some basic relations of general transformation, currents transformation and voltage in certain connections. The third part of bachelor‘s thesis shows some practical realization of spare connection models of basic transformer in Simulink program. In this part we modeled some current transformer models and voltage for single-phase and three-phase system. As to compare we have created process of currents and voltages in transformer as well as power and load of each model.
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Conceptual design of the reconstruction of an E.ON 22 kV distribution network installed at a specic area
Vepřek, Tomáš ; Nepevná, Vlastimila (referee) ; Blažek, Vladimír (advisor)
The aim of this thesis is a modification of the distribution network (DS) of the city of Brno to ensure power supply in the required quantity and quality for end consumers. Calculation of steady - state operation of distribution network (DS) of Brno is performed in the programme PAS DAISY Off-Line v.4.00 Bison. On the basis of available data (dispatching scheme, load current of stem lines and reserved power of wholesale customers) we will analyze the steady-state of network. We will find out which of the 110/22 kV transformer stations, cable and overhead lines are overloaded and perform network adjustments to ensure safe and reliable operation by 2015. We will identify in which year we will need to build a new power node in the northern part of Brno. The conclusion is focused on technical and economic evaluation of proposed alternative network arrangements.
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The inverter for arc-welding
Vaculík, Josef ; Klíma, Bohumil (referee) ; Červinka, Dalibor (advisor)
This diplom thesis theoretically deals about principle of pulse welding current source. Work explains operation principle of the single acting transmit converter used in realized construction and mention the others examples of converters types. Goal of the work is design individual parts of source : input filter, pulse transformer, output inductor and power semiconductors components. Thesis also contains description of the regulation circuitry of the converter, auxiliary power supply and pre-driver for power transistors. If everything will be all right prototype of the source will be assembled and measured. Results will be compared with theoretical assumptions.
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Optimalization of Induction Furnace Operation in foundry Vsetín
Trachta, Jiří ; Nowak, Stanislav (referee) ; Lázničková, Ilona (advisor)
The aim of this work is optimalisation of induction furnace in foundry for company PROMET FOUNDRY a.s. The company has two induction furnances. There are installed as identical construction. They have 2 modes of operation. First mode is founding and second mode is mode, where is temperature in maintain mode. Only one induction furnance can work in the founding mode at a time though. Inducion furnances are in the single-phase connection and they cause unbalance in the distribution network. Near the foundry there is a small network area whitch it is operated by company Zásobování teplem Vsetín a.s. The consumption of electrical energy in foundry so big, that in the year 2009 was made elaborate for Zásobování teplem Vsetín a.s. It was write at Laboratoře diagnostiky výkonů (Laboratory of performance diagnostics), which is a part of Electrotechnic Department at Technical Univarsity of Ostrava. The ordered study was named “Verification of causes of increased reactive energy consumption during transition from electricity delivery to electricity consumption”. The conclusion of this assignment confirms that in distribution network in the Jiráskova area in Vsetín there is unbalance of electrical energy and there is high part of reactive power. The next conclusion is crucial to find the customer who made the unbalance and to set relevant remedy. The last step will be the identification whether such device can actually be effectively balanced. It was subsequently proved that the Promet Foundry was causing the unbalance and that balanced consumption would be reasonable. Promet Foundry thus addressed Autel a.s. company with an inquiry to make a study of removing the causes of the unbalance which is caused by current induction furnaces operation at a minimum possible cost, least possible influence on the performance and minimum construction changes concerning the building. In this thesis there will be some topics. The result of which will be introducing of used heating technology, introducing of company and of effective plant performance and subsequent suggestions of possible unbalance removal or reactive power decrease. Several ways which are being implemented in the industry in order to balance consumption will be described. A suitable balancing plant will be subsequently chosen and its parameters will be calculated.
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Inverter for arc welding
Matiaško, Maroš ; Huták, Petr (referee) ; Vorel, Pavel (advisor)
This bachelor’s thesis describes designing, paremeter rating and construction of welding source on the principle of high-frequency inverter. The main scope of work is to design a switching inverter for arc welding on the principle of the forward converter. Welding source is regulated for demand of constant current.
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Influence of skin effect, proximity effect and air gap on winding losses of HF inductors and transformers
Pitner, Tomáš ; Cipín, Radoslav (referee) ; Martiš, Jan (advisor)
The bachelor's thesis deals with power losses in the windings of high-frequency inductors and transformers. A detailed mathematical and qualitative analysis of the skin effect, proximity effect and leakage flux of air gap is performed, supplemented with the results of computer simulations using the finite element method. The thesis introduces analytical and numerical methods for calculating power losses in the windings of inductors and transformers and describes suitable measurement methods, which are further used in the thesis. For selected geometries of inductors and transformers, AC resistances of their windings are calculated using FEM and the results are compared with measurements on constructed prototypes. The winding geometries are also compared between each other.
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