National Repository of Grey Literature 96 records found  beginprevious83 - 92next  jump to record: Search took 0.01 seconds. 
The impact of distributed generation on 110 kV distribution system E.ON
Hajdú, Lukáš ; Vaculík, Petr (referee) ; Orságová, Jaroslava (advisor)
This Master´s thesis deals with problematics related to the connection of new decentralized power sources into electrical power grid. Due to advantageous legislative support of these new, especially photovoltaic power sources, a massive amount of these sources have been connected into the power grid between years 2009 and 2010. For theoretical understanding of processes during a steady-state, the initial parts of this paper are focused on a procedure which solves steady-state on every power line mentioned. When we speak of decentralized power sources connection, it is necessary to mention the connected legislative. National distribution grid operators in collaboration with national regulatory commission have decided on a legislative document Rules of distribution grid operation, which puts a set of demands and requirements on applicants wishing to connect a new power source to the grid. The text of this thesis is focused mainly on demands required after the latest change in 1/2010. Practical part of this work deals with verification of new power source influence on a related power grid and meeting the legislatively required demands. The most important demands are voltage change due to new power source operation and its transfer to other voltage levels, higher harmonics injection, power output fluctuation and last, not least, changes in load flow directions. For reasons previously mentioned an analysis is made and possibilities of reducing or removing of these influences are introduced. To achieve these goals, two computer programs, Siemens Sinaut Spectrum and NetCalc are used.
2D and 3D Simulation of Electric Fields of MV Source
Kováč, Martin ; Hruška, Ivan (referee) ; Orságová, Jaroslava (advisor)
In the master´s thesis author deals with simulations of electromagnetic fields and their applications in the electric practice at the design of electromagnetic devices. The first part of thesis deals with 3 electromagnetic field simulation softwares, their comparison and selection of the best software for the practical part of the thesis. The second part contains the practical applications of electrostatic and electromagnetic field simulation of HT power supply.
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.
Operational Evaluation of the Small Photovoltaic Power Plants Connected to the LV network
Černý, Jaroslav ; Mastný, Petr (referee) ; Orságová, Jaroslava (advisor)
The objective of this thesis is to perform practical measurements of two small photovoltaic power plants, compare the received results with a theoretical calculation, and evaluate how the two differ from each other. Measured data are divided into three groups. The first group evaluates an overall electric power production in the individual months and compares it with the theoretical presumption that is instrumental to a return of investment calculation. The second group shows us a development of electric power production during characteristic days. We can compare how an ideal day from the FVE production point of view looks like, in other words a sunny and clear-sky day, with the opposite case when it is cloudy and raining all day long. Another extreme is a rapid growth or a performance drop, which can happen in a pho-tovoltaic power plant and a time period when this situation can arise. The third group contains statistic data from the electric power production. They are processed in the form of histograms and polygons of production that graphically illustrate production decomposition into the individual months. These data can be instrumental to a decision making about the form of purchase, whether it is economical for us to use the so called green bonus or not.
Comparison of Instrument Transformer and Sensor Applications in Feeder Terminal REF 542plus
Hrycík, Tomáš ; Majer, Karol (referee) ; Orságová, Jaroslava (advisor)
The aim of this Master´s thesis is use of instrument transformers and sensors on field of industry protection. We will compare current and voltage transformers, current sensor – based on Rogowski coil, voltage sensor – based on voltage divider. By this measure devices, we can monitoring values of analog quantities in medium voltage switchgear. It is impossible to compare, measure and analyze without this measure devices. There is protection terminal REF542plus, which can compile this values. The REF542plus ability are measuring, monitoring, remote control and protection. First, we will discuss about theory of sensors and convential instrument transformers and analysis of analog signal. We will compare analog input channel on sensor´s analog module and transformer´s analog module. There are few differences between type of analog modules. For analog signal analysis are important frequency filters and Analog/ Digital Convertor (sigma-delta). We will describe functions and options of REF542plus. In practical part of this project, we will test protection functions of protection terminal. First, protection terminal will be connected to sensors. Second protection terminal will be connected to transformers. For testing we chose Earth-fault directional protection and differential protection. We will make only secondary tests. That´s mean, input analog quantities to REF542plus will be simulated by tester. In all we will verify quality of protection. We will focus on lower settings of protection and we will inject protection by low current. Objectives are testing of trip characteristics and measuring of trip time.
The effect of disperzed generation on power quality
Kružík, Martin ; Orságová, Jaroslava (referee) ; Drápela, Jiří (advisor)
This MASTER`S THESIS engages in connecting with dispersed generation into electrical network and their influence on power quality. This thesis sets out to make up simple dynamic model of Wind power station and model of simple network. At this model I would like to simulate influence its working on voltage’s characteristics in addition place. Besides this is necessary calculate voltage’s characteristics according present methods – factory energy rules [PNE]. And these results compare with results of simulation
Safe Uninterruptable Power Supply of Power Station Internal Consuption
Tomášek, Petr ; Přidal, Petr (referee) ; Orságová, Jaroslava (advisor)
This thesis examines issues connected to safe uninterruptible power supplies. The term safe uninterruptible power supply is used for an aggregate of devices providing power for appliances that participate in safe rapid shutdown of a power plant in case power from a usual source fails. The thesis is divided into two parts – theoretical and practical. Theoretical part deals with possibilities and ways of realizing an aggregation of safe uninterruptible power supply. Various devices that can appear in the section of a safe uninterruptible power supply are listed and each device is characterized. Appliances that can be provided for by the sources of safe uninterruptible power supply are mentioned as well. These appliances are listed in accordance with ČSN standard nr. 381120. The theoretical part concludes with new trends in realization of safe uninterruptible power supplies. One of these sources is a clean source technology that can also be implemented in various ways. Practical part contains a suggestion of a safe uninterruptible power supply for particular steam power plant. This suggested safe uninterruptible power supply consists of rectifiers, batteries, inverters and a dieselgenerator. Calculated parameters of each device at the conclusion of the practical part are followed by a diagram of the suggested section of safe uninterruptible power supply.
Dimensioning of Earthing System in HV Switchgear
Buršík, Roman ; Matuška, Marcel (referee) ; Orságová, Jaroslava (advisor)
My master's thesis is focused on grounding of HV switchgear. The aim of this work is to create a computer program intended for dimensioning of earthing networks. The earthing networks are the most convenient alternative in term of effective grounding and distribution of ponential. They are based on latiny a flat conductor network cables and connection of appliance parts to network. Introduction of the thesis is dedicated to explanation of grounding theory and to description of requirements essential for properly designed earthing system (dimensioning of earthing system). Following chapter brings description of computer program algorithm testing propriety of an assigned earthing network for a particular switchgear. The chapter also contains description of an user interface and explanation of all features, included in the program. Last part provides presentation of program utilization to particular numerical assignment.
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.
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.

National Repository of Grey Literature : 96 records found   beginprevious83 - 92next  jump to record:
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