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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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Design of 22 kV Cable Network in the Existing Complex of Faculty Hospital
Blažek, Tomáš ; Procházka, Aleš (referee) ; Orságová, Jaroslava (advisor)
This thesis describes the reconstruction network 10 kV HV networks in a teaching hospital in the transition to a new 22 kV voltage level according to valid regulations. The paper describes the current state of technological equipment and its gradual replacement with new technology at 22 kV voltage level in each power units so as not to limit the operation of the hospital. For this purpose, the new backup system for rotating spare resources. The thesis deals with new input distribution, which will serve as a transfer point between the customer and distributor of electricity as well as advance the existing technological equipment.
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Current transducer's characteristics
Čížek, Ondřej ; Bulín, Tomáš (referee) ; Huzlík, Rostislav (advisor)
In this bachelor thesis are described all used current transducers, the way of their function and at each of them are described their properties. After that is described program LabVIEW and measurement, which happened by using it with specialization on frequency characteristics and their evaluation.
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Controllable switching power supply 0-1000 V / 100 W
Hofmann, Oldřich ; Procházka, Petr (referee) ; Martiš, Jan (advisor)
The thesis deals with the design and construction of a switching power supply with output voltage adjustable from 0 to 1200 V and rated power of 120 W, which will be used to replace the existing high voltage power supply for the irreversible electroporation (IRE) device developed at UVEE FEEC BUT. The thesis focuses on a basic description of the IRE device, a description of usable converter topologies and a selection of the best topology for the required purpose. The selection of the control circuit concept and its design are also integral parts of the thesis. The final part of the thesis contains the assembly of the power supply and the measurement verifying its function.
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Short Circuit Currents in the Sokolnice 400 kV Switching Station with Direct 400/110 kV Transformation Applied
Vojtěch, Pavel ; Špaček, Jaroslav (referee) ; Blažek, Vladimír (advisor)
The destination of this Bachelor´s Thesis is to explore short circuit currents for voltage level 400 kV in the switching station Sokolnice before year 1995 and after this year, when came to installation of the convertor T402 and to voltage direct 400/110 kV transformation applied. The Thesis is detecting at relation as for three-phase short circuit do for single-phase short circuits, for 400/220/110 kV primary transformation variation in voltage and for variation 400/110 kV, the change which came after connection of the convertor T402. In base of this calculation will be explored the short circuit resistance rating switching station in agreement with parameters ordered by the comp. Inc. ČEZ Prague.
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Load flow analyses of reactive power in distribution system
Krátký, Michal ; Kašpírek,, Martn (referee) ; Topolánek, David (advisor)
This thesis is focused on issues with transmission of reactive power though the distribution line of E.ON area. The goal is to find out where and in what rate are overflows of reactive power and to project the correctional steps to minimize this overflow. In this solution, there were used data of dispatcher measurement, which were processed by created source code in Matlab. The processing was analyzed for final conclusion. There were discovered shortages in overflow of reactive power in transfer between distribution and transmission line and in unsuitably regulated capacity power factor in Planá power plant and wrong automatic regulation of turns in 440/110kV substation Dasný. The action to minimize overflows of reactive power was projected by decompensation reactor placed in T101 and T102 transformers in substation Tábor.
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Project of Outgoing Transformer Unit for the Photovoltaic Power Station
Hanák, Miroslav ; Procházka, Aleš (referee) ; Orságová, Jaroslava (advisor)
This master’s thesis engages in project of outgoing transformer unit for the photovoltaic power station. It describes project and its design documentation what conducts to practising of construction. It has compared investing to more expansive transformer what has lower loss. It describes charges of operation’s transformer in twenty years. It leads project of cable low voltage. It compares whether is better to use aluminium or cupric cables. Project is led with respect for investment costs and minimum of operation loss.
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