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.

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.

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.

Modern technology and fast development of heat pumps, the hunt for savings in energy consumption and the strive for environmentally friendly energy sources, convenience, and financial profit, have made heat pumps a reasonable alternative for the heating of houses.When the heat pump starts it will consume a considerable amount of current, which may result in a short-lived voltage-drop if the power grid is weak compared to the start-up current.The company Fortum Distribution which owns and administrates electrical network is interested in an investigation that deals with heat pumps affect on the quality of electricity.The purpose of this investigation is to study fast electrical fluctuations (Flicker) as a result of start-up currents for single as well as multiple heat pumps on the same electrical station and from this evaluate whether there will be any problems installing heat pumps..

The master thesis ?Mechanical Integration of an IR-detector in a Micro Cooler? has beenperformed at FLIR Systems AB in Danderyd. FLIR Systems is a world leader in the design,manufacture and marketing of thermal imaging camera systems.The thesis project is divided into to two areas, Production Method and Noise.The Production Method concerns the positioning of a detector on the cold finger within the IRcamera.The detector has to be positiond with very high accuracy at the center of the cold finger,so it can be placed in line with the optical axis to avoid movement of the picture during zooming.The positioning of the detector is at present done with the help of specially designed guides on aplate on top of the cold finger. The design workes well but the special machining needed for thisplate is very expensive.The goal concerning the production method was to derive a new more cost effective method forthe assembling and positioning of the detector on the cold finger by replacing the guides on theplate with a reusable equipment or some other alignement operation.Several concept ideas have been generated with the help of concept generation methods in theform of concept classification trees and concept combinational tables. Two of these conceptswere selected to be further refined.

I Forsbacka har det uppstått klagomål angående elkvalitén. Elkvalitetsproblemet är aven typ som kallas Flicker eller flimmer på svenska. Ljusutbytet från glödlampor ärspeciellt känsliga för vissa spänningsvariationer som får ljuset att uppfattas somflimrande. Ett sådant ljus kan vara mycket störande och påverkakoncentrationsförmågan hos människor som vistas i ljuset och kan även undermedvetetpåverka individer som inte är medvetna om problemet.Forsbacka är ett mindre samhälle med ca 1800 inv. och har en elintensiv stålindustri.Tidigare mätningar visar på stort Flicker i området och tyder på att störningarna kankomma från subtransmissionsnätet som Forsbacka är inkopplat till.

Forskning kring förändringsblindhet har hittills undersökt hur fenomenet gör sig gällande i naturliga situationer och vanliga visuella scener. Denna undersökning syftar till att testa hur förändringsblindhet framträder vid användning av webbsidor samt att undersöka vilka typer av förändringar som är lättare respektive svårare att upptäcka på dessa. 20 studenter testades med datoriserade bildspel utformade i fyra kategorier av förändring. Rensinks Flicker paradigm användes som förändringsmetod. Resultaten visade att; det var lättare att upptäcka en förändring som inte består av en bild av en person än en med en bild av en person och det är svårare att lokalisera en förändring på vänster sida än på höger.

AbstractWrite the most important things first in text that will be read by a scanning web user. This paper is based upon theories about? how we read? what style in texts is? how texts should be written for web pagesReading from computer screens is about 25 percent slower than reading from paper. This because screens? Flicker? have lower resolution than paperAll text with the purpose of being read from a screen should be adjusted to the reader?s physical condition.

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.

Flimmer (eng. Flicker), beskrivs av standard EN 50160:1999 som ett visuellt intryck av instabilitet orsakat av ljusintryck som varierar intensitetsmässigt eller spektralt över tiden. Flimmer är alltså en variation i ljusstyrka som orsakas av en ändring i spänningsnivån, spänningsfluktuationer. När spänningen ändras uppstår en variation i lampans ljusintensitet som ögat uppfattar som en blinkning. Denna spänningsändring behöver inte vara större än 1-2V med 230 V matning för att lampan ska blinka till.

The interest in small-scale electricity in Sweden has increased strongly in recent years. The interest is noticeable both among politicians to increase the share of renewables in the energy mix, and among electricity consumers to partially replace purchased electricity with self-produced. This has resulted in a significant increase of electricity production in low voltage grids in recent years, and the trend appears to continue in the coming years. The majority of the new production plants are solar cells, followed by wind turbines, and it is also in these the greatest efforts are made in this paper.Distributed generation is often seen as something positive since it will contribute to reduced transmission losses and reduced voltage drop in the networks, and that it increases the share of electricity from renewable sources. In cases where the grids are not strong enough, or in other ways not adapted to manage the installed production, power quality may be adversely affected.

The interest in small-scale electricity in Sweden has increased strongly in recent years. The interest is noticeable both among politicians to increase the share of renewables in the energy mix, and among electricity consumers to partially replace purchased electricity with self-produced. This has resulted in a significant increase of electricity production in low voltage grids in recent years, and the trend appears to continue in the coming years. The majority of the new production plants are solar cells, followed by wind turbines, and it is also in these the greatest efforts are made in this paper.Distributed generation is often seen as something positive since it will contribute to reduced transmission losses and reduced voltage drop in the networks, and that it increases the share of electricity from renewable sources. In cases where the grids are not strong enough, or in other ways not adapted to manage the installed production, power quality may be adversely affected.