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438 Uppsatser om Numerical grid - Sida 2 av 30

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..

VSM och 16 förluster

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.

Diskontinuerliga Galerkinmetoder för initialvärdesproblem och prissättning av optioner

Efficient numerical methods for option pricing is an active field of research. This project has the goal to examine possible ways to improve an established method of numerical pricing. The method is based on an adaptive finite difference method in price and uses the backwards differentiation formula of order 2, BDF2, in time. The project will focus on improvements to the time integration through implementation of discontinuous Galerkin methods, dG. Empirical convergence and accuracy results are obtained for equidistant dG-methods up to order 3 and performance is compared to BDF2.

Automation i Distributionsnät

As a part of Göteborg Energi?s work towards a smarter electric grid, the company has chosen to investigate the possibilities of automation in their middle voltage grid. In Europe, there are example cases where these technologies already are installed which many articles on the CIRED conference 2011 proved. Netcontrol Oy in Finland has, together with Tekla, created an automated SCADA system that Vattenfall in Finland today uses. The grid mainly consists of 10 kV open loop fed city grid and this automation is mainly designed for this type of grid.

CFD simulering av en fyrtakts Otto motorcykel motor

This thesis deals with the numerical 3D simulation of a four stroke, spark-ignited, internalcombustion engine, which is mounted on a high performance motorcycle. The work, carried outin collaboration with Politecnico di Milano and MV Agusta, focuses on the simulation of theintake, compression and expansion stroke, including combustion simulation, using an opensource CFD code.Simulation of internal combustion engines offers a great challenge in the field of CFD research.Moving boundaries of the solution domain, caused by the motion of the piston and valves, leadsto deformation of the computational grid, with decreasing quality of the solution as result. Basedon this, a previously developed mesh motion strategy was employed where a number of meshesare used to cover the whole simulation cycle. Within each mesh interval the internal cell pointsof the mesh are moved to account for the boundary motion of the piston and valves. This strategywas previously applied to simplified geometries as well as real engine geometries.

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.

Gridens svar på överlevnad : -en studie om revisorers beaktning av fortsatt drift

An auditors? job is to review the company's figures and, as an independent part, give an accurate picture of its financial situation. Auditors have to relate to ISA where ISA 570 can be found and which deals with the going concern. The standard addresses a couple of factors that may be indications that a company can have problems with their continued operation. The problem is that ISA does not evaluate the events, which is more significant than others in the assessment, but it is up to the auditor to consider.The purpose of this paper is to describe the factors, which the auditor believes is more important than others in assessing the going concern and explain why it is so.

Affärsmöjligheter med Smarta Elnät : En studie som undersöker möjligheter och hinder i utvecklingen av det svenska elsystemet

Distributed, renewable generation-units and more efficient use of electric power,demands a developed electric grid. This grid is often referred to as the ?Smart Grid?.This future electric system rise expectations among actors in the existing electricmarket. International organizations share visions of opportunities for electricityconsumers and new actors, ready to enter the market. At the same time, electricutility companies may question the need for some of these upcoming changes, as theyare sometimes expected to lead the development.This paper therefore seeks to investigate the business opportunities related to SmartGrids.

Effektiva Lagringsmetoder för Glesa Matriser

Sparse matrices are often used in numerical algorithms that solve linear equation systems. Many methods for storing sparse matrices have been proposed and implemented during the years. These methods focus primarily on minimizing the total memory consumption and the time that it takes to store a sparse matrix. This report researches the available storage methods for sparse unstructured matrices. The formats that are researched and implemented are COO, CRS and ELL.

Konkurser i små aktiebolag: En studie ur konkursförvaltares perspektiv med stöd av repertory grid -

De senaste åren visar statistik på att allt fler små företag går i konkurs. Bara under 2013 ökade siffran med fem procent gentemot tidigare år. Därför ämnar denna studie att belysa problematiken till varför konkurser uppstår samt vilka bakomliggande signaler företagen tar emot om en annalkande konkurs. Det är inte ovanligt att företag av olika anledningar bortser från signalerna de får om företagets ställning. Studiens huvudsyfte är att öka förståelsen för signaler vid företagskonkurser.För att besvara syftet har studien en kvalitativ metod med kvantitativa inslag.

Analys av spänningsstabilitetsberäkningar i det svenska elsystemet

Numerical simulations play a vital role in both static and dynamic stability assessment of electric power systems and the foreseeing of voltage collapse. Simulations performed by Svenska Kraftnät(SvK) are mainly done in the specialized voltage collapse predicting software tool, SPICA and the more all?purpose software tool, ARISTO.The grid operators at SvK use SPICA to predict the maximum transfer limit at specified sections (in this report the section in concerns is the southern part of Sweden i.e. interface1 4). SPICA is mainly used as an online application by using actual states from the grid, these states update every quarter of an hour.This thesis is a continuation of the master thesis SPICA ? ARISTO JÄMFÖRELSE by Jakob Katzman and Johan Fält.

Vindkraft och elbilar på Öland år 2020 : Är smart laddning av elbilar lösningen på ett framtida flaskhalsproblem?

The Island of Öland has one of the best wind climates for land based wind power in Sweden. An objective for the Island is to become self sufficient using electricity from renewable source of energy such as wind. There is currently 55 MW capacity installed on the Island and it is estimated that grid congestion will occasionally occur if more than 135 MW was installed.The aim of this thesis is to investigate he possibilities for load management by smart charging of electric vehicles, EV. The definition of smart charging is that the charging is done to some extent with an ICT-system, (information and communication technology) that correlates wind electricity generation to the charging of electric vehicles. The purpose is to avoid grid congestions on the sub-sea cable that connects Öland to the mainland because that in turn would curtail wind energy production.

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.

vindkraftens påverkan på elkvaliten

This thesis concerns how the power quality in the grid is affected by the connection of wind power plants. As things are at present, Fortum Distribution AB has a number of wind turbines and wind parks connected to the own grid. As the pressure on building and connecting additional wind power is increasing, so is also the interest of how the already existing wind power generation affects the power quality in the nearby distribution grids. The study is performed by direction of Fortum Distribution AB and is limited to the 10 kV/40 kV-grid in Bohuslän, Sweden. The methods for calculation of power quality are compared to the results of a number of measurements.

User Experience utvärderingar med stöd av Repertory Grid Technique

Studiens syfte var att undersöka möjligheterna att använda intervjutekniken Repertory Grid Technique (RGT) som utvärderingsteknik för att utvärdera User Experience (UX) på distans. Detta gjordes genom att de föreställningar som en handledarstödd utvärdering resulterade i jämfördes med det resultat som uppnåddes genom en webbaserad variant av samma utvärdering. Studiens resultat visade på en svårighet för respondenterna i den webbaserade utvärderingen att formulera föreställningar som går att använda för analys av en produkts UX. Diskussionen pekar på en tänkbar lösning i form av förstudier som utförs med en mindre grupp av respondenter för att på detta sätt hjälpa utvärderarna att skapa sig en referensram att använda vid tolkningen av de föreställningar som sedan kan samlas in under en webbaserad utvärdering. Studien syftade även till att jämföra vilka aspekter kopplade till UX som utvärderingarna genererade, samtliga av dessa kopplades till subjektiva eller produktrelaterade aspekter..

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