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10560 Uppsatser om Grid-group theory - Sida 2 av 704

Simulering av vindkraftverk och närliggande elnät vid Risholmen i Göteborg i SimPowerSystems

With background in the rapidly growing need to find solutions for sustainable energy production and the increasing interest for wind power, this report was written. With take-off point from the wind power plant Big Glenn, which has been built in the harbour of Gothenburg, a model of the adjacent power grid has been created in Simulink/SimPowerSystems. Parameters for the power grid and its components has been provided by Göteborg Energi Nät, that has also been the supplier of measurement data of produced power, the power need from loads in the vicinity, voltage levels, current values and also the variation of power factor at the wind power plant.The SimPowerSystems model has been used to perform simulations of power flow in the grid. These simulated values have then been compared to the measured values to verify the functionality of the model. Further, the model has been used to perform simulations of a grid fault, which causes a voltage drop.

..."för att solen gick inte ner"...... : En studie om morfologi och syntax hos vuxna andraspråksinlärare

Our essay is about the grammar structure that the participants in A- and B- level of a school in the middle of Sweden, in the subject, Swedish as a second language, process. We have collected written productions from an A-level group and a B-level group and made a comparison between them morphologically and syntactically according to the processability theory by Pienemann.Processability theory was applied to Swedish by Pienemann & Håkansson (1999), with five steps in syntax and four steps in morphology. It turned out that the B-level group had much higher processing level of grammar than the A level group and one of the reasons for this can be that grammar is explicitly taught during the first year of studying Swedish as a second language in the school we have chosen to study..

Koncerninterna vinstöverföringar - finns det någon strategi?

The purpose of our essay is to find out if there are any strategies for profit transactions in a group. To realise our purpose we conducted two case studies with interviews. But we can not draw any general conclusions.To conduct the research we had to build a theory. In this theory we found motives to do profit transactions and how to do it. We also thought that there had to be some conflicts between the motives and the manager´s interests.In our analysis we found that financing the dividend was a strong reason to make profit transactions between companies in the group.

Trafikverkets effektstyrningssystem - EFS 132 kV : Bidraget till minskade förluster

The technological legacy from the early electrification of the Swedish railroads has resulted in a power grid with a lower grid frequency than the national power grid from which it is fed. Energy transfer between these power grids with different frequencies requires substations, adapting the grid frequency for the rail road power grid. For this purpose, a feeding power grid has been built, stretching across the country from Boden in the north to Tälle/Häggvik in the south.Power transfer in the Swedish power grid results in voltage angle differences which increase with increasing loads and transfer distance. These voltage angle differences are transferred from the power feeding substations to the rail road power grid, will in some extent cause loss of energy due to unwanted power flows from north to south.To minimize the losses due to this phenomenon, a power management system called EFS 132 kV has been developed and implemented. The system minimizes the unwanted power flows and controls the desired power flow for a good distribution of loads between the power feeding substations.This thesis investigates the extent of the transmission losses avoided due to the EFS 132 kV that coordinates the idling angles to a common reference point.The results indicate that EFS 132 kV affects the power flow, especially between the northern substations through an improved load distribution.

Risk- och sårbarhetsanalyser för smarta elnät

The electrical grid needs to be changed in the future in order to manage more distributed and renewable generation and also to make it possible for electricity consumers to be more active and aware of their electricity consumption. This future grid is usually referred to as a smart grid. With the transition to a smart grid, new challenges occur. One method to determine those challenges is to perform risk and vulnerability analyses. InStockholm, the new urban district Stockholm Royal Seaport is built.

Undersökning av elkvalitet i distributionsnät med omfattande vindkraftselproduktion

The goal for this master thesis project has been to investigate the power quality in adistribution grid, which has a high fraction of dispersed power production due towindmills. The study has been done on a grid in Laholm South of Halmstad, whereapproximately 45 windmills are connected to the distribution grid owned by SHKEnergi. The investigation has been focused on to two radialy fed 20 kV lines, wheretwelve windmills are connected.Voltage variations have been studied by creating a model of the grid in the simulationprogram SIMPOW. The largest deviation that has been found in any point of the gridis ±1.9 % of the nominal voltage. This deviation is a result of varying powergeneration from the windmills and the voltage regulation at the connection point ofthe line.

En vindkraftparks inverkan på Gävle Energis elnät

The effects from a planned wind farm on the grid utility Gävle Energis electrical grid have been studied. The wind farm is planned to be built in the forest 15 km north of Gävle and will have 23 turbines with rated power from 2 to 2.5 MW, resulting in a total installed power between 46 MW and 57.5 MW. The grid connection will be made at 70 kV. The aim of the analysis was to determine what effects the wind farm would have on the power grid in the form of electrical disturbances (flicker etc.), need for new investment and raised operational cost. To allow the connection of the wind farm technical solutions (new lines, power stations and grid reinforcements) have been constructed.

Berättelser om livet, mödraskap och gruppen

In 2007 the Prevention Unit at Södermalm in Stockholm started a group activity for parents and children. The group activity?s intention is to offer families support in their early interaction. This study is a part of providing knowledge about this intervention. The purpose of this study is to describe and analyze the stories which are produced by five participants in a support group for parents and children.

Värmning av avloppsvatten med spillvärme för att förbättra kvävereningen -Temperaturens inverkan på kvävereningen

The goal for this master thesis project has been to investigate the power quality in adistribution grid, which has a high fraction of dispersed power production due towindmills. The study has been done on a grid in Laholm South of Halmstad, whereapproximately 45 windmills are connected to the distribution grid owned by SHKEnergi. The investigation has been focused on to two radialy fed 20 kV lines, wheretwelve windmills are connected.Voltage variations have been studied by creating a model of the grid in the simulationprogram SIMPOW. The largest deviation that has been found in any point of the gridis ±1.9 % of the nominal voltage. This deviation is a result of varying powergeneration from the windmills and the voltage regulation at the connection point ofthe line.

Komponentuppdelning av elnätetpå lokalnivå

Sweden will, in accordance with the EU-directive 2003/54/EC, move from post-regulating the electricity power grid-tariffs by using a fictitious grid, to a regulation in advance which uses the actual power grid as a starting point. For this purpose a component breakdown of the grid needs to be made to determine the value of the network and by that the tariff price that is reasonable for the network business in question to charge.The primary breakdown criteria is the voltage-level and type of region. Voltage-level is crucial for the cost and complexity of a grid-part, because the higher the voltagelevel is, there are more and stricter laws and rules to follow. This work is limited to the distributionpart of the grid, in other words voltage levels from 20 kV and below.The type of region is crucial to the type of components you can and want to use. In city environments both overhead-wires and independent substations are undesirable for both practical, safety and aesthetic reasons.

Utveckling av Innovativa Småskaliga Elförsörjningskoncept : - Minor Field Study i Namibia

A large part of the Namibian low income population lack access to grid distributed electricity. This mean they are effectively shut out from basic functions such as lighting, information technologies and hygienic food handling. Hence, finding ways of providing affordable off-grid electricity is an important, not to say critical, task.This master thesis is an innovation and concept development project that has been carried out in cooperation with organisations in Sweden and Namibia. The purpose of the project has been to (1) develop a concept for off-grid electricity supply in Namibia and (2) to gain a deeper knowledge within the area of innovation and product development for the Base of the Pyramid population, i.e. the poorest, but largest, socio-economic part of the global population.Essential in this project has been to acquire user understanding and to identify user needs to create a foundation for developing the concept.

Utvärdering av viktmåttbaserad reglering av lokal- och regionnätens resursbehov

The Energy Market Inspectorate is implementing a new tariff regulation in Sweden. A small part of the new regulation concerns effectible operation costs and originally they where intended to be calculated using a modification of equivalent comparison standards, in Swedish Ekm. This thesis is intended to analyze if Fortums grid in Stockholm could be described correctly, using equivalent comparison standards. In Ekm every part of the distribution grid is designated a weighting in relation to 1 km 0.4kV over head line. These Ekm-measurements are intended to simplify comparison between different grid areas with different structure and geographical conditions.

Elmätarens roll i framtidens elnät : Ett samarbete med Sweco Energuide AB och Mälarenergi Elnät AB

The initial aim of the roll out of smart electricity meters in Sweden was to allow remote readings of the households? monthly electricity consumption for billing purposes. Since then the transition towards a smart grid has become a more prioritized matter. In the roll out of next generation smart meters more attention is therefore given to how the Distribution System Operator (DSO) can benefit from the meter through different smart grid applications. This study uses a qualitative research method to identify three general fields of application and 15 specific concepts corresponding to ways in which the DSO can create added value from the information provided by the smart meter.

SocialSurf: ett verktyg för social navigering i webbläsaren

Today, we can see that social navigation is embedded in different kinds of websites, but there is still little support for social navigation in the web browser. Our main concern has been how we construct a tool that fills this hole in the web browser. By letting the theory, the prototype and the focus group serve as input/output to each other we could create a better overview of how the different pieces were intertwined. This has been a crucial mental model for us to obtain since it has helped us to understand how we could realize the theory through our prototype and thereby come to the conclusion of what aspects of the theory that we should put forward to further development. After constructing the prototype we thought that it would support social navigation, but realized after analyzing the discussion of the focus group that we are not there yet.

Textile Grid

Textile Grid är ett undersökande textildesignprojektsom utforskar olika tekniker och material för atttänja på gränserna i textil. Utgångspunkten ärett enkelt rutmönster som översätts i teknikernatryck, väv och trikå. Rutmönstret fungerar som enkonstruktion i textilen och genom att jobba medkontrasterna mellan hårt och mjukt, samt rörelseoch stabilitet utforskas både textilens utseendeoch rörelse. Resultatet är fem material som viksoch formas efter sin egen konstruktion..

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