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Influence of RES to power system in Czech Republic
Vánišová, Michaela ; Bartošík, Tomáš (referee) ; Mastný, Petr (advisor)
This text deals with renewable energy sources in terms of working on the electricity network of the Czech Republic. There is the definition of renewable energy sources in the work. Next there are discussed the basic information about connecting to the distribution network. In two parts, there is mentioned and discussed the issue of operation of renewable energy resources and their effects in terms of the electricity network. The last chapter is focused on the possibility of further utilization of renewable energy sources because of their natural energy.
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Uninterruptible Power Supply
Mrázek, Petr ; Harabiš, Vratislav (referee) ; Chmelař, Milan (advisor)
The thesis deals with Uninterruptible Power Supply (UPS) and associated problems of backup power in case of unexpected outages of electricity. Start of work is dedicated to limitation of the electricity supplies, as well as their causes and consequences. Furthermore, brief history of UPS and subsequently distinguish between UPS’s architectures. There is also a description of the energy sources such as batteries, flywheels or fuel cells. Part of thesis describes security of electricity supply in health care facilities, including requirements for emergency power. The own design of UPS is described in the end.
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Monitoring in Middle- and Low-Voltage distribution systems penetrated by distributed generation
Kolacia, Tomáš ; Kolář, Vladimír (referee) ; Drápela, Jiří (advisor)
This thesis concerns monitoring in Middle- and Low-Voltage distribution systems penetrated by distributed generation. Monitoring itself means measuring voltages and power flows and sending relevant data to the supervisory system. The first part of the thesis describes distribution systems with differences between individual voltage levels. The following chapter is focused on consequences of high share of renewable energy sources in distribution systems. Most of the problems are partially resolved by technical conditions for connection of the new power sources. However, difficulties with voltage regulation and uncontrolled power flows to higher voltage levels remain. These are the reasons for measuring voltages and currents in medium voltage networks. Second to last subhead of this chapter is dedicated to possible benefits of monitoring. The fourth part of the thesis deals with voltage and current sensors with their advantages and disadvantages. The best suitable devices are chosen in the end of the chapter. It is crucial to mention that sensors are only part of measuring system. Analog outputs from current or voltage transformers need to be converted to digital signal and further processed. After that required quantities are finally sent. Properties of these circuit cards are described in the sixth chapter. Following part aims to define a certain key that will determine the suitable locations for installation of the measurement. The final part of the thesis compares measured voltages and power flows from real 22 kV network with calculated values from computer program PAS DAISY Bizon.
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Steady state and short-circuit conditions within E.ON 110kV power network at bridge operation of transformers T402 and T403 in 400/100kV transformer station Sokolnice
Bernát, Jan ; Rampl, Martin (referee) ; Blažek, Vladimír (advisor)
The master’s thesis deals with a calculation of steady state and short-circuit conditions in a 110 kV system during a bridge operation of transformers in a Sokolnice substation. The theoretical part of the thesis deals with a calculation of steady state of a system using Newton’s iterative method, it investigates short-circuits – their timing, distinctive values and a method of their calculation. In the practical part the 100 kV grid supplied from Sokolnice substation is described. The main goal of the thesis is a comparation of two basic wirings: bridge operation of T202 and T203 transformers (contemporarily in service) and bridge operation of T402 and T403 (in service after 2017). These two wirings were controlled even during one state of emergency during which the Sokolnice substation will be affected by an outage of one busbar. Voltage conditions, loading of power line and transformers and overall power balance were controlled. Short-circuit conditions were also calculated and short-circuit resistance of particular substations was inspected. In the conclusion technical measures needed to ensure smooth bridge operation of convertors T402 and T403.
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Proposal of design and configuration of 22 kV network after installation of 110/22 kV transformation in Brno-Sever switching substation
Mišinger, Ondřej ; Beneš, Jan (referee) ; Blažek, Vladimír (advisor)
The theoretical part of this thesis deals with distribution networks in terms of distribution according to different criteria, describes the main elements of electric distribution networks and their qualities. The following describes the methods of calculating the steady state of electrical networks. These methods are nowadays used as basics for computer programs. In the penultimate chapter of the theoretical part are summarized the principles for the development of present networks and construction of new electrical networks. The aim of practical part of the thesis is to assess the current condition of the network 22 kV in the city of Brno and assess the condition after installation of 110/22 kV transformation in Brno-Sever switching substation. After evaluating the results of steady state electrical network and identifying certain problems is the following aim a proposal of solving problems that emerged in the network. The result should be operational, functional and reliable electric distribution network. This thesis used to calculate the steady state electrical networks by software PAS DAISY Off-Line Bizon V4.
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Integration of Photovoltaic Power Plants in the Electricity System
Michl, Pavel ; Paar, Martin (referee) ; Mastný, Petr (advisor)
The thesis discuses an integration of photovoltaic power stations to electric network. The first part describes connecting conditions of small sources to distribution system, including administrative requirements, feasibility study, and requirements to the energy meters, measuring, control devices, switching devices and protection. The second part is aimed to describe problems of the photovoltaic system. Solar radiation generating and reducing of its intensity incident upon the earth surface are described in this part. The quantum of produced electric power depends on climatic conditions in the fixed area, seasons, etc. This work also discusses the types of photovoltaic cells and their actual efficiency. Inverters are further important components of the photovoltaic system. The parameters of the inverters have a great influence on the total actual efficiency of the photovoltaic system. Different methods of the photovoltaic panels’ connection with the inverters and their advantages and disadvantages are also mentioned. The supporting structure of the photovoltaic panels and eventually transformer are further important components of photovoltaic system. The work also analyze the methods of connection of the photovoltaic power station to distributive low voltage and medium voltage network, electric energy accumulation and possibilities of the sale of produced electric energy. The large number of the connected photovoltaic power stations has negative influences to electric network. The third part contains the design of a photovoltaic power plant with a capacity of 516,24 kWp on the scoped area in southern Bohemia. The project documentation for the location where the power plant is designed is also made. It contains the design of photovoltaic panels, the design of the inverters to get an optimal power load. This part also contains a calculation of the photovoltaic system losses and the design of transformer and the cable junction calculation of the distributive system. The feasibility study of the power plant connected to distributive system is also conducted. Its delivery rate will be connected to the distribution point Řípov (110/22 kV). The calculation results show us that this photovoltaic power plant can be linked to the distribution system. The final part of this paper contains an economic estimate of the photovoltaic power plant operating and the calculation of the return. An Economic return is influenced by the wide range of values that affect the total return rate. The calculation of an operating economy is made for several variants. The return rate in refer to contemporary redemption price for 2010 with no consideration for a bank loan is 7 years. If we consider the bank loan it would be 12 years. The penetrative reduction of the redemption price is expected for 2011. Calculation works with the decline of 30 %. It would extend the rate of return to 11 years without a bank loan or to 22 years with the bank loan. The bank loan is considered to cover 80 % of the investment.
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Influence of Distributed Generation on Given Area of 22 kV Distribution Network
Samuel, Tomáš ; Bráblík, Libor (referee) ; Orságová, Jaroslava (advisor)
The Thesis deals with the current problem related to the connection of dispersive sources to the distribution network. The advantageous legislative support, however, gives a rapid rise to the sources of this kind. Current pricing philosophy favours in particular the growth of photovoltaic power plants. The introduction is aimed at the dispersive sources locating so as to give a comprehensive solution and better understanding of this issue. The equipments of this kind are located in accordance with legislation in force; however, it is necessary to formulate the possibilities of placing them from the view of rational use of the area with the aim of the public weal accordance of both public and private interests. Talking about connection of the new dispersive sources to the distribution network, it is important to mention the legislation, legal directives and regulations delimitating this kind of trade. This theme is the subject of another chapter of the work. Particular attention is paid to the regulation on conditions of connection to the distribution network. When connecting the sources to the distribution network the biggest technical problem from the view of electrical engineering is undesirable influence on the quality parameters (voltage) in this network. This is in particular the voltage change after connection, then, depending on the type of source, the emission of the current harmonic, sharp voltage change, etc. Considering current rise of the dispersive sources connected to the distribution network, more and more influence will appear in quantity parameters. For this reason there will be a lot of search for the methods of preventing from the negative influence on the network. From all of the above said reasons, the work is aimed at the operation analysis of the part of the distribution network, calculation of the network qualitative parameters and searching for the methods of negative influence rectification owing to switching processes of the distribution system. So as to determine the quantitative parameters we used the E-influence programme. Final paragraphs are devoted to the changes to come not only in legislation but, in general, in the approach of the distribution system operators not only to the ways of another connection of such sources but even the regulation of the dispersive sources already connected.
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Dispersed production and its influence on distribution network
Kácl, František ; Vybíralík, František (referee) ; Mastný, Petr (advisor)
The diploma thesis deals with dispersed generation (production). The small electric power sources are connected into distribution networks. Types and principles of the small electric power sources are studied. The legislation framework concerning renewable energy sources utilization is described. These power plants have impact into distribution networks and therefore techniques for the source connection to distribution network are included in the thesis. The impact of the specific small source of electricity must be studied.
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Design of the expansion of 22 kV distribution network in a specific part of the city of Brno
Lakomý, Vojtěch ; Nepevná, Vlastimila (referee) ; Blažek, Vladimír (advisor)
The goal of this thesis is to design measures of the distribution network in Brno to ensure a supply of electricity to its consumers in required quantity, quality and reliability. This project will be solved in the program called PAS DAISY Off-Line v.4.00 Bizon. At first we make an analysis of the steady state of the distribution network. We check load of transformer stations 110/22 kV, overhead and cable lines if they operate in allowed limits. Then we complete or correct reserved power drains of big consumers of electricity in the model of distribution system. From the calculation of the steady state of the distribution network we will probably find out that some parts of the system are overloaded. Therefore we suggest changes for it (like switching over circuits, installation of new transformer stations and circuits), which should ensure safety and reliability of operations in the distribution system.
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Cluster analysis of more dimensional data by a neural network
Helcl, Zbyněk ; Křivan, Miloš (advisor) ; Berka, Petr (referee)
The topic of the present thesis is an analysis of a sample data archive containing measured values of real and reactive power. The measurement in question took place in late 2006 and early 2007 using MEg40 recording measurement devices disposed in a station for transforming high voltage to low voltage in the Pražská energetika distribution network. The procedure of processing measured values, the preparation thereof for a subsequent processing by a neural network, and a final statistical evaluation of determined individual clusters -- typical daily take-off diagrams -- will be described. The results of the present thesis may be applied in the making of predictions of electrical energy consumption at a particular transformer station.
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