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Overloading and short circuits of electric wires
Jurman, Jiří ; Valenta, Jiří (referee) ; Šimek, David (advisor)
The bachelor's thesis discusses the requirements that must be met in practice for electrical distribution systems in terms of the construction and securing of electrical distribution systems against the effects of current overload and conductor shorts according to the relevant Czech and European standards. Furthermore, the work marginally focuses on standardized thicknesses and materials used precisely for insulation. From the point of view of residential wiring of Czech residential distributors and distributor's homes, to compare different conditions in terms of requirements for wires connected to electricity meters. Furthermore, the work certainly refers to programs that are used in practice for the design of electrical elements and conductors for specified electrical parameters based on the parameters themselves, such as the consumption of equipment connected to the electrical distribution. In the thesis, we can find some programs used in practice for this purpose, including a description of their functions and a subsequent comparison of these programs and a model design using a program used in practice. Finally, the thesis evaluates the performed measurement of the influence of the released Joule integral determined using the K2S2 value and, in the second part, determined by the limiting class of the circuit breaker.
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Design of a transformer station for power output from a PV power plant and a diesel generator
Marák, Jiří ; Procházka, Aleš (referee) ; Orságová, Jaroslava (advisor)
This thesis is about design of a transformation station for power output from both a photovoltaic power plant and a diesel generator, serving as grid support. The primary objective is to devise a comprehensive solution including conceptualization, grid connection point, and transformer specifications capable of handling the 5 MW power output from the PV plant and the 1000 kW output from the diesel generator, including the calculation of short-circuit conditions. Furthermore, the thesis delves into the design of network breakpoints and protective measures.Lastly, it proposes dispatch control and billing metering in accordance with the operational requirements stipulated by the distribution system operator.
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Validation of the tool for localization of symmetrical and asymmetrical faults
Šmehlík, Daniel ; Jurák, Viktor (referee) ; Topolánek, David (advisor)
Disturbances in power systems that can cause widespread outages and limit power supply require rapid detection, location and elimination. Earth faults and short circuits, each with their own complications for localization, pose significant challenges to power operations. This thesis focuses on the validation of Vdip, a tool designed to efficiently locate these faults. The tool was tested in two simulation environments, RTDS and PSCAD, to simulate different fault scenarios and record data for analysis. These tests provided important information for evaluating the effectiveness of Vdip.
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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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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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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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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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Assessment of connectivity of the new source to the 110 kV network
Kopečný, David ; Fojtík, Martin (referee) ; Orságová, Jaroslava (advisor)
This thesis focuses on the connectivity problems of the new sources to the electrical network. The first part of the thesis deals with the description of the new source and the method of its connection to the electrical network. Furthermore, in work, there are elaborated the blocking conditions for substation TR Neratovice expanded distribution point. A distribution network operator must receive an attachment application for connecting before the actual connection. The attachments consist of study cases of conjunction that values the inverse influence on the distributional network and informs the operator about the required measures for the reliable service with the new source. PSS Sincal computer software was used to survey the inverse influences on the distributional network. Based on processed data, the evaluation of conjunction of the synchronous generator to the grid at TR Neratovice substation was reconsidered.
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MV Overhead Line Protections and their Coordination with Autoreclosers
Šoustal, Petr ; Skala, Petr (referee) ; Orságová, Jaroslava (advisor)
The aim of this Master’s Thesis is to describe protections for overhead lines in distribution networks. Here are described requirements for the protection and the basic protections. Protections are divided according to their protective function. For each protection is given its use and its power plans. It is stated in the work setting of protection in the real network. On this network is simulated place with short-circuit and described the action of protection. The work also deals with the coordination of protection with automatic circuit breakers. This chapter shows that, given the selectivity is not possible to deploy two or more reclosers (remotely-operated switches) to the core network management. The next chapter describes two representatives reclosers available on the Czech market OSM 27 and GVR 27. Chapter describes and compares their performance characteristics. Conclusion the work includes a proposal protected the lead in incorporating automatic circuit breakers (remotely operated circuit breakers and reclosers). The proposal is based on two different levels of annual number of interruptions and duration of annual general interruption of electricity supply. For these levels the company EGÚ Brno, a.s. proposed several variants of the use of remote-controlled in terms of reducing the cost of the penalty. Our task was to choose a variant that would be applicable in the real network. Reducing costs is feasible only in the limits Ln = 6 failures / year and Lt = 720 min / year, where the selected option No. 4. The limits Ln = 8 failures / year and Lt = 1,080 min / year, not in the real network may no option in terms of selectivity.
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