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Evaluation of pressure conditions in the quenching chamber of low-voltage device
Nevrzal, Filip ; Vávra, Daniel (referee) ; Valenta, Jiří (advisor)
In this master’s thesis there is firstly conducted research about pressure measurement. Next there is mathematical description of thermodynamic conditions in used testing chamber by using magnetohydrodynamic and Maxwell equations. Next chapter deals with testing chamber itself, more precisely with function, model and changes done to it. In practical part there are data measured by used sensors, which are also closer described in this chapter. In next chapter there is comparison of reaction times of used sensors and their frequency specters, obtaining using fast Fourier transformation. Second to last chapter introduces very measurement on the real device and in the last chapter these data are analyzed and more closely described.
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Design of a 22 kV network in the Lipno area after the integration of the new 110/22 kV transformer station
Žižlavský, Jakub ; Koudelka, Jan (referee) ; Ptáček, Michal (advisor)
This diploma thesis deals with the design of a new 110/22 kV substation in Horní Planá. The substation design addresses, for example, the issue of reducing the load of surrounding power lines from 110/22 kV substations, reducing the size of short-circuit ratios in the surrounding system, reliability and continuity of supply, etc. Furthermore, loads of individual outgoing feeders from the surrounding substations are analyzed, in case they will be connected to a new substation. Following this, the work also addresses the related new decay points of the lines, which are determined by calculation and simulation in the Grizzly program. The simulation results could be used to compare the current load status of individual lines and contribute to the assessment of the possible benefits of both the new substation and the implementation of other modern technologies for faster and more efficient measurement and handling during operating and fault conditions.
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Line protection against overload and short circuit
Konšel, Ladislav ; Vaněk, Jaromír (referee) ; Valenta, Jiří (advisor)
This work includes a theoretical treatise on the operation of electrical wiring for the overload and short circuit. This is mainly on thermal effects of over current and their influence on the properties of conductors and insulation. Work Includes links to determine the load current, depending on the properties of leadership and its surroundings. It also deals with the protection of conductors against overload and short circuit. The work includes measurements process of warming wires. Practical project of proposal circuit is created using SICHR. The project includes proposals of conductor’s sizes and safety components for both residential building and individual flats.
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High-voltage/low-voltage prefabricated substantions
Loveček, Michal ; Šafránek, Ivan (referee) ; Haluzík, Evžen (advisor)
The diploma thesis is dedicated to modern kiosk-type transformer substations PET, that are used when modernizing distribution network. Since such substations are placed on publicly accessible places it is really important that they are safe for service staff as well as for the public. Apart from the highest characteristic values stress is put upon the safety. Right construction, functionality and safety is verified using the type-tests as stated in ČSN EN 62271-202. In the last part of the thesis there are the methods and procedures of type-testing described.
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Analysis of parallel operation of nodal areas of 110 kV Krasikov and Neznasov transformers stations
Kostkan, Petr ; Kopička, Marek (referee) ; Ptáček, Michal (advisor)
Currently, the nodal areas of Neznášov substation and Krasíkov substation, which belong to ČEZd distribution network 110 kV – East, are operand as separate units. In the defined setting, each nodal area comprises of two 400/110 kV transformers. In the case of failure of the transformer T401 or T402, the criterion N-1 for twenty percent of the rated output is not met. Such problem can be solved by parallel operation of nodal areas of Neznášov substation and Krasíkov substation. The principal as well as practical aim of this thesis is to interconnect the bridge operated connection in separated areas into parallel/loop operation of nodal areas (supplied by 400/110 kV transformers). Computing software is used to calculate the steady state and short-circuit conditions in the distribution network 110 kV for separate and parallel operation of mentioned nodal areas. Power flow analysis is aimed at assessment and evaluation of voltage conditions, transformers loading (400/110 kV and 110/vn) as well as 110 kV lines loading. Obtained short-circuit indices is used to examine short-circuit, withstand capability of the 110 kV substation. Finally, benefits as well as drawbacks of the separate and parallel operation are compared and evaluated. If necessary, the technical arrangements are proposed/designed in order to allow parallel operation of nodal areas Neznášov substation and Krasíkov substation.
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Steady state and short-circuit conditions in 110kV E.ON network fed from Sokolnice transformer station
Vyčítal, Václav ; Rampl, Martin (referee) ; Blažek, Vladimír (advisor)
This thesis can be divided into five main parts. The first part deals with theoretical analysis of power flow calculation in power network during steady state condition. Load flow calculation is presented here as a linear and nonlinear problem. Newton iteration method is proposed for solving power flow as nonlinear problem. The second part of this thesis deals with the analysis of short-circuit calculation in accordance with valid International Standard IEC 60909. The equivalent voltage source method is adopted in case of the short-circuit calculation. For the calculation of unbalanced short-circuit currents, the symmetrical components method is also presented. The last three parts of this paper are focused on calculations of power flow and short-circuit conditions in power grid Sokolnice. So in the third part is the description of nodal area Sokolnice with its substations and the calculation of load flow and short-circuit conditions for two different power supply options. For each supply option is also considered an abnormal (fault) grid condition. (overall there are solved four different options) The fourth part of this thesis deals with the result analysis and also the results of different power supply options are compared. In the last part there are presented necessary technical improvements for fault-free operation of power grid Sokolnice based on the result of power flow and short-circuit conditions in that grid.
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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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Stabilized operation and short - circuit conditions within E.ON 110 kV power network supplied from Čebín 110kV switching station, during the period of 2011
Chrástek, Radim ; Janda, Petr (referee) ; Blažek, Vladimír (advisor)
The aim of this thesis is to project an operation of bridge connection in distribution network in Čebín’s nodal area. The main task is to check a fulfilment of voltage tolerance in distribution substations 110 kV, load transformer control (400/110 kV, 110/VN kV), distribution power line 110 kV control and short - circuit conditions control. Relevant calculations are performed by dispatching control system, which works with the actual parameters of all distribution network‘s 110 kV facilities. The theoretical part of this thesis is devoted to the way of the calculation of stabilized operation and the short-circuit conditions. In practical part, first we perform an analyse of stabilized operation and the short-circuit conditions of distribution network 110 kV in actual operation. Next step deals with bridge connection design and analysing its operation. The operation of bridge connection is verificated even in specific conditions (disturbance state, increased load). The next section evaluates the results of the calculations. First we deal with actual operations evaluation and proposed the bridge connection. In the next section we evaluate the operation of the bridge connection in the specific operating conditions. Finally, we evaluate the losses in the distribution network 110 kV. If the calculations of the stabilized operation or the short-circuit conditions of distribution network discovers that some of its elements are overloaded, we propose changes to ensure safe and reliable operation of the distribution network.
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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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