• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 44
  • 9
  • 7
  • 3
  • 1
  • 1
  • Tagged with
  • 67
  • 49
  • 10
  • 10
  • 9
  • 8
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Měření částečných výbojů u vysokonapěťových kabelů / Partial discharge measurement of middle and high voltage cables

Pelikán, Luděk January 2018 (has links)
The main topic of this work is the analysis of the measurement of partial discharge measurements on high voltage cables. The thesis also deals with other measurements, including the measurement of the loss factor and the voltage retention and breakdown test. Part of the text describes the issue of partial discharge, its measurement by galvanic method and methods of elimination of disturbing influences that affect this method in terms of sensitivity and accuracy of the measured values. Thesis also describes the construction of the cables, their marking and the tests carried out on them. There is also a description of the cable terminals used for measuring, especially water terminals, which are designed for high voltages and which are carried out in the practical part of the thesis. The next part deals with problems prior to the commissioning of water terminals and their preparation for certain tests, including description and evaluation of the results of the measurements.
52

Návrh rekonstrukce distribuční sítě v zadané oblasti / Proposal of the reconstruction of a distribution network in a specific area

Richter, Miroslav January 2008 (has links)
The dissertation describes several types of low and high voltage distribution networks including their implementation in specified location with regards to the reliability and quality of electric power supply. The distributions networks are classified according to ways of cable routing, distribution line voltage levels as well as according to types of network interconnections. The high and low voltage distribution networks are further categorized based on used cable types, where, more attention is paid to insulated lines used in the Czech Republic, low voltage lines called „AES“ and „PAS“ high voltage lines used more and more during the distribution network reconstruction. Attention is also given to the description of used methodology for the calculation of network performance stability. An individual part of the dissertation is devoted to a low voltage distribution network proposal in the village of Kovalovice. Based on performed analysis of distribution network conditions, several reconstruction versions were proposed with the help of „KASI“ software, the description of which is also included. The proposed versions are further analysed for both, technical and economical aspects and is selected most suitable version of the distribution network.
53

Návrh transformační stanice pro vyvedení výkonu z fotovoltaické elektrárny / Project of Outgoing Transformer Unit for the Photovoltaic Power Station

Hanák, Miroslav January 2009 (has links)
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.
54

Návrh rekonstrukce distribuční sítě v dané lokalitě / Proposal of the reconstruction of the distribution network in a specific area

Novák, Vojtěch January 2009 (has links)
This diploma thesis is concerned with reconstruction of distribution network in Hruba Vrbka. The diploma thesis is divided in two parts. For better understanding to this issue, the first theoretical part is shortly dedicated to the history of electrical power system, to the several types of distribution network of low voltage and high voltage and their utilization in the area, considering the reliability and the quality of delivery of the electric energy. In this thesis there is mentioned division of distribution grids according to placing of cable lines, according to voltage and according to type of grid connection. Next part of this work is dedicated to the description of overhead lines and cable lines and their characteristics. For the proper concept of the grid we should know some characteristics of the electric line’s proposal: mechanical strength, warming, voltage drop, efficiency, degree of safety and provision of delivery. In the end of the theoretical part there are described methods for calculation of grid’s steady state as a linear task and also non-linear task, elimination of the balancing node, the iterative method, the reduction of external power take-off nodes and the solution of the steady state of the network through the direct current model. The second part of the diploma thesis is concerned with the calculation of the steady state in the village Hruba Vrbka. In this part is also described the KASI program which was used for the calculation of the grid’s steady state. Firstly low voltage grid’s balance in Hruba Vrbka was found out and evaluated and then there were proposed some solutions of the reconstruction for the grid improving. The suggested options of the reconstruction are considered from technical and economical point of view and the best solution is chosen. For this solution there is suggested the protection through program SICHR 9. In the end of this diploma thesis there is checked the load of the high voltage line.
55

Bezdrátový optický spoj / Free-Space Optics data link

Šála, Jakub January 2010 (has links)
In this thesis, shows a current issue for free space optics, limiting their use in practice with regard to the availability and reliability. They conducted measurements on wireless optical links and the observed values is calculated by the availability of the connection. Subsequently, measurements are performed on alternate versions of wireless and copper connections. Observed values were compared with a wireless optical link. It is made of optical design of wireless connections at home.
56

Analýza vyvedení elektrického výkonu v městské zástavbě / Analysis ofelectrical output from the power plat working in the middle of town

Hrubý, Radek January 2012 (has links)
The work focuses on outlet of the electrical power from power plants operating in urban areas. After a short analysis of the general possibility of leading out electric power from power plants of various types, thesis continues to describe of outlet electrical power from PPC Červený Mlýn. Subsequently, are calculated short-circuit conditions in the main switching station. It follows an analysis of power lines. The last part dealt with the issue of reliability of sources in connection with random transition processes in the electrical network and the light of the operational reliability of electrical power equipment.
57

Výpočet tepelného pole rozvaděče UniGear 500R / Calculation of heat and force field UniGear ZS1

Mokrý, Lukáš January 2015 (has links)
The aim of my work is to describe high-voltage switchgear type UniGear 500R, which is part of UniGear switchgears family. I will focus on heating issue of one 500R unit and its parts during operation. Maximum values of this heating is limited by standards and can´t be exceed to ensure safe and reliable operation. That is why the heating tests are necessary part of designing and developing switchgears. Calculation will be made by two different ways. First is classic one-pole heating net method and second is numerical simulation in Solidworks flow simulation program. Except the theoretical description there will be presented also used 3D model and explanation of both method, used to calculation and simulation. Last point of this work is measuring of this type of switchgear and getting real data. The main point there is to compare measured values with values calculated and decide if is possible to simulate tests with appropriate accuracy. Then would be also possible to substitute the real test in laboratory, which costs many thousand crowns and takes lots hours of time. This work is collaborated with EJF division of ABB Company, where I am employed. Heating issues in this company is always on process, because of developing and improving of their products. So this work could be helpful in this field. ABB provides all materials needed, especially technical catalogues, 3D model and final values from laboratory measuring. Support from college faculty is mainly in study consultations and proposing of calculations making. In the end of work will be make final comparison and evaluation of achieved results.
58

Rekonstrukce budovy pivovaru s předpjatými stropními deskami / Reconstruction of the brewery structure using post-tensioned ceiling

Zavadil, Bronislav January 2013 (has links)
Aim of this master's thesis is an optimized design of locally supported ceiling slab of building of social center with account of span of columns and height of slab. Structure must be assessed in terms of limit state and service limit state by ČSN EN 1992-1-1 General rules and rules for buildings after design.
59

Statické řešení střešní konstrukce / Static design of roof structure

Duda, Tomáš January 2014 (has links)
The subject of the diploma thesis is the design and static analysis of roof structure. It is prestressed roof shell (membrane) supported by a cable. The whole thesis is divided into several separated units according to task's specification. The text section describes the introduction to the issue of presstressed suspension cable constructions and displays their possible shapes, types and realizations. There is also technical report of solved shell, which was written on the base of the documents, drawn drawings and structural (static) analysis.
60

Průzkum a návrh rekonstrukce zděného objektu v Medlicích / Diagnostic and Reconstruction Design of Brick Building in Medlice

Košárek, Jan January 2014 (has links)
Master’s thesis deals with diagnostics and reconstruction of neo-gothic chapel in Medlice. Summary of appropriate testing methods for this chapel is compiled. Visual examination of whole structure have been performed by diagnostics. Masonry element strength was found out at specimens which had were taken out from structure (drill cores and whole bricks). Masonry elements also was tested by Schmidt hammer LB. Mortar was tested by Kucera’s drill. Masonry strength required for static calculation was computed from achieved values. After examination of all structure defects have been designed reconstruction by post-tensioning.

Page generated in 0.0356 seconds