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  • 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.
1

Standardiserad tillverkning av nätstationer

Nesrine, Elsaleh January 2008 (has links)
<p>AbstractAbetong in Falkenberg manufactures, among other things, small prefabricated concrete buildings for housing various installations, such as electric transformers.The aim of this dissertation is to reduce the time needed to design such buildings, by way of finding a number of standardized buildings. Standardized in such a manner as to incorporate both the needs of the manufacturer (Abetong) and its customers.To analyze the needs of the parties the work has included a market survey and calculations on the strength of these buildings.One survey was a letter questionnaire to all of Abetong’s customers who have, in the past, ordered these types of building. The aim of the questionnaire was to establish how the customers want these buildings designed.Another survey conducted was an inventory of all of Abetong’s previous projects where these types of building were manufactured. The aim of this was to ensure that the customer’s words and deeds coincide.The results from these two surveys show that not always do the customers buy what they say they want in the questionnaire. The results and possible explanations can be found in the report.The conclusions, and the decisions on how to standardize the buildings, were based on the surveys and discussions with Abetong to ensure that as many wishes as possible were met.The dissertation also includes design calculations on the strength of different parts of these buildings.The calculations have been performed according to the current Swedish codes BKR03 and BBK04.Many of the calculations have been carried out in an Excel-programme especially developed for this project. The programme calculates the dimensioning loads and the necessary reinforcement.</p>
2

Standardiserad tillverkning av nätstationer

Nesrine, Elsaleh January 2008 (has links)
AbstractAbetong in Falkenberg manufactures, among other things, small prefabricated concrete buildings for housing various installations, such as electric transformers.The aim of this dissertation is to reduce the time needed to design such buildings, by way of finding a number of standardized buildings. Standardized in such a manner as to incorporate both the needs of the manufacturer (Abetong) and its customers.To analyze the needs of the parties the work has included a market survey and calculations on the strength of these buildings.One survey was a letter questionnaire to all of Abetong’s customers who have, in the past, ordered these types of building. The aim of the questionnaire was to establish how the customers want these buildings designed.Another survey conducted was an inventory of all of Abetong’s previous projects where these types of building were manufactured. The aim of this was to ensure that the customer’s words and deeds coincide.The results from these two surveys show that not always do the customers buy what they say they want in the questionnaire. The results and possible explanations can be found in the report.The conclusions, and the decisions on how to standardize the buildings, were based on the surveys and discussions with Abetong to ensure that as many wishes as possible were met.The dissertation also includes design calculations on the strength of different parts of these buildings.The calculations have been performed according to the current Swedish codes BKR03 and BBK04.Many of the calculations have been carried out in an Excel-programme especially developed for this project. The programme calculates the dimensioning loads and the necessary reinforcement.
3

Analys av mätdata från nätstationer / Analysis of data from secondary substations

Eklöf, Martin January 2014 (has links)
Fortum has in a pilot project installed metering equipment with wireless communication in secondary substations in Stockholm. So far, the collected data are used only in specific projects. This master thesis was carried out at Fortum Distribution AB in Stockholm during 2013. The purpose of this study is to simplify and enhance the use of data in for example network planning process, by giving suggestions on how data can be managed and giving examples of analyzes that collected data can be used for. The electricity meter which Fortum has installed is a EDMI-Mk10A which is set to measure max/average/min values with a one hour time resolution of the following parameters: voltage (per phase), current (per phase) andactive power and active and reactive energy. In order to analyze the collected data an analysis tool is required. During this thesis two customized tools in Microsoft Excel have been developed, one for sorting data and one for analyzing. One aim of the thesis is to show examples of what collected measurement data can be used for. This work shows an example of analysis of active power, power factor, voltage, occurrence of interrupts and the relationship between outdoor temperature and power. This master thesis has among others resulted in the following advice: Expand the number of secondary substations with measuring equipment. Higher time resolution. Measure apparent power and temperature.
4

Elnätsprojektering på distributionsnivå

Lövström, Cecilia January 2016 (has links)
Projektarbetet har gått ut på att vädersäkra elnätet i ett glesbebyggt område öster om Falkenberg i Hylte kommun. Genom att skriva rapporten har man fått en mer fördjupad kunskap hur en projekteringsprocess av ett distributionsnät fungerar och hur de olika komponenterna påverkar miljön. Detta har genomförts på ett modernt och branschförankrat sätt med hjälp av lämpliga verktyg och beräkningar. Datorprogrammet Digpro, dpPower, har används för att placera ut komponenter och kabelvägar för att utföra samtliga beräkningar för elnätet. Därefter har platsbesök utförts i det aktuella området för att stämma av att kartinformationen stämmer med verkligheten. Genom att utföra kontrollberäkningar för hand i enlighet med svensk standard SEK Handbok 444 har man i rapporten försökt att finjustera beräkningsresultaten från dpPower och därav minska på materialåtgången. Projekteringen har utgått från E.ONs tekniska riktlinjer som är ett dokument som ställer krav och allmänna riktlinjer hur en projektering skall utföras i E.ONs elnät. Resultatet av arbetet har inneburit att befintliga luftledningar och stolpstationer kommer att rivas och ersättas med nya jordkablar och markstationer. Elnätet är uppbyggt i radiellt utförande på grund av långa ledningssträckor mellan stationerna och med få anslutna kunder. Genom att förlägga jordkabel blir nätet mer leveranssäkert. Den beräknade kostnaden för projektet uppgår till ca 3,7 miljoner kronor.
5

Underlag till energieffektiviserande åtgärder i nätstationer / Basis for reduction of energy losses in secondary substations

Krantz, Sebastian January 2014 (has links)
Umeå Energi are working towards a goal, that in the year of 2018, they will be completely climate neutral. As a part of this, one target is to reduce their grid losses by 4 % of the 2012 level, which corresponds to an overall reduction of the grid losses of just over 1.7 GWh. In many residential areas, the distribution grid is designed and rated for electric heating as the heating in the houses. As many of the houses later has been converted to other types of heating, their electricity use has decreased and the total power output from many of the secondary substations has decreased significantly. Because of this, many of these stations today are well oversized, which in turn means that the energy losses in these stations are unnecessarily high. In this degree project, 25 secondary substations have been studied, all located in residential areas in and around central Umeå. All of the stations have an installed capacity of 1600 kVA, evenly distributed over two transformers, with 800 kVA each. For each station the annual energy losses has been calculated, and based on economy and environmental factors, various actions has been presented and recommended. The actions are either direct, which means they only require that transformers are turned off during all or part of the year, or long-term, which means they require investments. The recommended direct actions for these 25 stations, will lead to a potential energy loss reduction of 188 MWh per year, which corresponds to 70 000 SEK or 118 tons of carbon dioxide emission. This represents approximately 11 % of the total target in energy loss reduction and can be done immediately, with no need for investments. For long-term actions a possible 424 MWh can be reduced, which would represent about 25 % of the target, although that would require an investment of 5.12 million SEK.
6

Magnetfält alstrade kring nätstationer i samband med lokaldistribution av elkraft : Magnetic fields generated by electrical substations during distribution of electric power

Strömberg, Fredrik January 2012 (has links)
Abstract: This report covers primarily the work of documenting electromagnetic fields generated by one of the later parts in the electrical power distribution chain: The electrical substation, wherein 10 kV is transformed to 400 V for use by private consumers. Thus it is one of the most widespread and frequently occurring parts in the Swedish power grid and of particular interest, as electrical substations are found everywhere in populated areas, often in close vicinity to people and animals. The report deals with a number of formulated questions and/or hypothesis’ stated at the onset of the work undertaken, theory that is relevant for the topics the report covers, the details of the field work undertaken and the following analysis of the readings, which in term provide answers for the questions stated in the beginning. It also covers what is the currently known short term and long term risks associated with electromagnetic fields in the power frequent spectrum and of varying intensity in the vicinity of humans. The analysis also provides recommendations and identifies several points to carefully consider when planning for new installations or replacements of some parts of existing installations. For enhanced reading comprehension there is, aside from sections with pictures and attached explanatory texts and templates, several graphs, one-line diagram and maps of the power grid among the appendixes to the rapport.
7

Projektering av elnätet för ett exploateringsområde / Planning of electric power distribution for an exploitation area

Abbasi, Ziwar, Bernebrand, Anna January 2018 (has links)
Det växande invånarantalet i Sverige har under det senaste decenniet lett till ett stort behov av nybyggnationer av bostäder. Till följd av detta har nybyggnationer av bostäder ökat kraftigt. För att bemöta kapacitetsbehovet krävs stora investeringar från elnätsbolagen för att kunna ansluta de nytillkomna bostadsområdena samt för att möjliggöra utbyggnad av ny infrastruktur. Expansionsmöjligheterna som har uppstått i den aktuella kommunen har lett till utbyggnad av elnätet för ett nytt bostadsområde. Syftet med projekteringen är att hitta en rationell lösning för att kunna förse ett exploateringsområde bestående av 19 bostäder med elektricitet. För att uppnå ett önskvärt resultat med projekteringen har företagsriktlinjer och branschstandarder använts. Det projekterade distributionsnätet utformas av radiellt system, vilket innebär att matning enbart sker från ett håll. Distributionsnätet är uppbyggt av två olika fördelningssystem: TN-S och TN-C. Projekteringen omfattar även nätberäkningar som utförts med både optimeringsprogrammet NetBas och även manuellt. De parametrar som har beräknats är spänningsfall, kortslutningsströmmar och utlösningstider. Dimensioneringen av distributionsnätet, som utfördes endast med hjälp av NetBas, resulterade i placering av en nätstation, fem stycken kabelskåp, 0,9 kilometer lågspänningskabel och 0,13 kilometer högspänningskabel. Projektets totala investeringskostnad har approximativt beräknats till 568 000 kronor. / The growing population in Sweden has led to the great need for new housing construction in the last decade. Consequently, new housing construction has increased substantially. To meet the capacity requirement, large investments are required from the electricity grid companies to connect the newly built residential areas and to enable the development of new infrastructure. The expansion opportunities that have arisen in the current municipality have led to the expansion of the grid for a new residential area. The purpose of the project is to find a rational solution to provide an exploitation area of 19 homes with electricity. To achieve a desirable result with the distribution planning, corporate guidelines and industry standards have been used. The projected distribution network is designed by a radial system, which means that power supply takes place only from one direction. The distribution network is made up of two different distribution systems: TN-S and TN-C. The distribution planning also includes network calculations carried out with both optimization software NetBas and manually. The parameters that have been calculated are voltage drops, short-circuit currents and short-circuiting time. The dimension of the distribution network, is calculated only through NetBas, it resulted in the installation of a network station, five cable cabinet, 0.9 kilometers low voltage cable and 0.13 kilometers high voltage cable. The project's total investment cost has approximately been estimated at 568 000 Swedish crowns.
8

Tidig detektering av fel i mellanspänningsnätet

Johansson, David January 2016 (has links)
Dala Energi Elnät is a smaller grid company with network operations consisting of the distri-bution and measurement of electricity. The company is interested in acquiring greater know-ledge of the error detection equipment that can in a early stage detect errors in the medium-voltage network. Which hopefully results in faster fault location and cost savings for the company.The purpose of this study is to investigate the fault-detection equipment that would fit into the Dala Energys medium voltage grid and what experiences others electricity companies have with fault-detection equipment. Fault detection equipment used in the study has been limited to equipment from the companies Protrol AB and dLaboratory AB. Structure and function of the equipment are investigated and empirical experience obtained through a telephone interview and a visit on the electricity network companies Kraftringen respectively Falu Elnät AB.Protrols fault-detection equipment consists of error detectors that measure only the current for detecting ground faults and over currents and mainly used in substations. Communication to the control center can be made by fiber, Ethernet or signal cable. The simplest detectors have no communication link without signals with LED indicator on the substation if the fault current passed. Configuration, settings, and registered error events must be downloaded by USB connection on site.dLaboratorys concept is that the industrial PC installed in a distribution substation, where the current and voltage are measured in each output tray, to detect ground faults and overcurrents. Relay Protection functions are available on the PC, which means that both fault detection and protection equipment available. Information from the measurements sent to dLaboratorys serves for analysis and transmitted to power grid owner. On dLaboratorys website the information can then be reviewed with a convenient interface.Selection of fault-detection equipment is affected by electricity network design with radial or meshed networks, existing grid equipment, relay protection, geographical distance and communication facilities etc. Where a comprehensive solution from a longer term perspective should be taken into account. Recording options in error-detection equipment can be used to better understand the reasons why a protection relay trips, where the events before and after the fault can be analyzed. A financial investment in fault-detection equipment do not always pay for itself, but also provides greater customer benefits and opportunities to identify weak points in the grid. Benefiting from successful experience of other grid companies have had with fault-detection equipment.For the fault-detection equipment included in the study, recommended Protrols equipment to be used on radial parts of the network, where the error detectors are not placed in each substation but strategically where geographical distances are great to reduce troubleshooting time substantially.dLaboratorys fault detection equipment is best suited to distribution stations with many exhausting tray and where it is possible that if sectioning out the fault with remote-controlled switch or circuit breaker. dLaboratory relay protection has worked well in conducted tests on the other hand it remains to be seen how it manages in normal operation. / <p>Validerat; 20160617 (global_studentproject_submitter)</p>
9

Analys av mätvärden från lågspänningsnät för att verifiera nätberäkningar och lokalisera icke-tekniska nätförluster

Homman, Rebecka January 2021 (has links)
In 2018 the Swedish government introduced a new legislation for the electricity meters installed in the low voltage networks. The legislation includes, among other things, that the electricity meters should be able to measure the current and voltage per phase with a time resolution of one hour or 15 minutes. To meet the new requirements Falu Energi &amp; Vatten have started a rollout of new electricity meters in their low voltage networks. In addition to this, electricity meters have also been installed in a few secondary substations in Falun. The overall purpose of this project was to investigate what the data from the new electricity meters can be used for and what the benefits are with having metering equipment in secondary substations. Data from secondary substations can be useful when dimensioning the grid or when analysing power losses. During the project, data was collected from one secondary substation and the underlying low voltage network. The parameters current and voltage were measured per phase with a time interval of 15 minutes. The data was used in three different investigations. The results from two of them indicated that the network information system that Falu Energi &amp; Vatten uses for dimensioning tends to overestimate the power consumption and the voltage drop between the secondary substation and the low voltage customers. In the last investigation a method for localising non-technical power losses was evaluated. The result indicated that the method was not suitable for the purpose.
10

Framtidens distrbutionsnät : Vilka krav kommer ställas på framtidens nätstationer?

Gåsste, Gabriel January 2017 (has links)
I en traditionellt konservativ bransch rör det sig nu snabbt. En snabb ökning av andelen förnybar elproduktion gör att det uppstår en rad nya utmaningar som måste lösas. Den här studien är en undersökning av framtidens distributionsnät och har ett fokus på nätstationerna. Studien visar att en ökad mängd distribuerad generering kan göra att dagens skydd inte fungerar som tänkt. Samtidigt ökar kraven på våra elnät. Detta medför att nya skydd kan behövas. Man ser också att automation ökar vilket minskar avbrottstiderna. Det undersöks också vilka elenergilagringssystem som finns och kan vara aktuellt i distributionsnätet. Studien visar att ett Li-Jon batterilager kan fylla flera olika viktiga funktioner åt olika aktörer, detta öppnar för flera olika inkomstkällor samtidigt som kostnaderna sjunker. Detta gör att det kan bli möjligt att energilager blir en vanligt förekommande komponent i distributionsnätet.

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