Orust Kretsloppsakademi is a nonprofit organisation, with a goal of annually generate the same amount of electrical energy that is consumed. Orust is an island on the west coast of Sweden, north of Gothenburg. The population of 15 000 reaches 40 000 during summer, due to the large amount of vacationer. The total electricity demand is 174 GWh a year with a maximum power need of 32 MW. This report presents an analysis for the plausibility of their plan and from a Power system stability perspective, the effects on the electrical grid.The conclusion is that the restraints for development of power generation from wind, solar and wave generation, are the power systems capability to transfer power, primarily in the transformers of the grid.

Svenska Kraftnät is (together with the other transmission system operators of the Nordic power system) responsible for keeping balance between the generated and demanded power in the Nordic power system. Spontaneous load variations and system disturbances, however, lead to power imbalance followed by frequency variations. The frequency deviations can be limited to an acceptable level by the spinning reserve, mainly by hydro power control. But there are also other system properties which have a great influence on the frequency and system stability. The frequency and voltage dependence of the loads have a direct influence on the power balance.

This master thesis has been performed at Solvina in Gothenburg for Skellefteå Kraftand Vattenfall Eldistribution. The aim of it is to investigate the consequences of theinstallation of a wind power plant on the mountain Uljabuouda in the vicinity ofArjeplog. Especially the impacts on voltage and transient stability are examined.Furthermore, the amount of extra strain on the voltage regulation equipment and theneeds for increased regulation capabilities are looked into.The wind power plant is planned to be built by Skellefteå Kraft and connected to a130 kV grid owned by Vattenfall Eldistribution. The work comprehends the followingmain parts:- Theoretical studies aimed at wind turbines and Power system stability issues.- Modelling of the type of wind turbines assumed to be built on Uljabuouda.- Simulations of different operation cases and analysis of the simulation results.The results from the simulations show that, as far as voltage stability and extraworkload on tap-changers are concerned, the wind power plant does not, in anysignificant manner, worsen the present conditions. The problem of overloading theline between Arvidsjaur and Vargfors is also minor.

The power system modelled in this thesis work has been developed for simulationwhen e.g. the production in some part of the power system is changed. The powersystem has been modelled according to the swing mass of the system, the frequencydependency of the load and the turbine governor. The model determines the systemfrequency, the period of regulation and the power exchange between the differentsubsystems in the Nordic synchronized system.In this model the system frequency is assumed to be the same in all different parts ofthe power system and the voltage conditions in the power system are neglected. Forthat reason power swings does not occur between different subsystems in the powersystem, which usually occur as a result of the swinging connection between thetransmissions line.

Hydropower is an important source of energy in Sweden and accounts for about 46 % of the total energy production. Sweden has about 1 200 hydropower plants and with the intention of raising the pressure head of the water and to store water, dams are built by the power plants. The storage reservoirs make it possible to adjust the energy production by demand and season. Dams in connection to the reservoirs are subjected to additional loading during periods of high floods or when an icecap in the winter is formed on the reservoirs. In order to maintain the dam safety, the power companies in Sweden are working with guidelines for dam safety from RIDAS.

Both the German and the Nordic power markets are seeing dramatically changed conditions due to an ongoing process of expanding the share of renewable production in the systems. For the German part this comes from heavy subsidies which have led to an explosive development in installed capacity of photovoltaic and wind based production. After the Fukushima incident it has been decided to shut down all Germanys nuclear plants. This capacity drop is however not of the same magnitude as the increase in renewables, but will impact the stability of the power system. The Nordic power system which already has a surplus of power sees an even further increase, coming mainly from construction of new nuclear plants in Finland and a general increase in wind farms.

TitleSystems, Stability and Power. The Discourse of Information in Organizing Knowledge.AbstractThe aim of this Master's thesis is to inquire into the consequences of an unequal distribution of power between information discourses in the field of knowledge organisation. A deconstruction of Jennifer Rowley's and John Farrows introductory textbook Organizing Knowledge from 2000 is related to the major discourses of information in LIS. Questions posed in this study are: What meaning is ascribed to information in the material studied? Which information discourses are given a dominant position? Which are excluded? and: How does this affect the construction of the library and information science student's identity, in relation to practices of knowledge organisation? The theoretical framework is provided by Ernesto Laclau's and Chantal Mouffe's theory of discourse and combined with techniques for text analysis originating from the work of Norman Fairclough.The analysis reveals a strong domination of a cognitive discourse of information that underlines the importance of information systems for the organisation of knowledge.

A detailed dam safety evaluation (in Sweden called FDU) was performed in 2009 by WSP where stability control was performed for Långströmmen power plant with associated spillways. This evaluation concluded that stability could not be ensured, and risk of sliding occurred. The evaluation is based entirely on the recommendations outlined in RIDAS, the power companies guidelines for dam safety, and it is clear that extensive renovations are necessary to stabilize the dam.In this work, the stability will also be checked with guidance through new proposals on guidelines for concrete dams sliding stability, ELFORSK?s report 08:59. This report considered the guidelines in RIDAS as oversimplified, both from an international perspective, but also with regard to the current state of knowledge regarding dam safety.

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.

This master thesis describes the development of an UPS module. UPS is an acronym for Uninterruptable Power Supply. The UPS module has been developed at the company AerotechTelub AB. The UPS module delivers the necessary voltage and current in case of a power interrupt. If a power interrupt occur, the computer system has one to three minutes available to store data and shut down correctly.

Linux is a growing operating system in embedded systems. Today, Linux is not only in heavy servers but also in cell phones, PDAs, cameras and other devices running on battery power. While current technology is more energy efficient, more and more technologies are implemented into a single unit resulting in an overall increase of power consumption.Low power consumption is an increasingly important feature of a system today. Lower power consumption means lower costs, less environmental impact, and longer life for applications that runs on batteries.This work compiles methods to reduce power consumption of Linux systems. The work includes examining whether the available opportunities are platform-specific or of a more general nature.

In industry applications, such as power supply plants, the issue of interaction between fluid and structure is always presented. More precisely, the fluid flow affects the structure by applying force(s) on it and vice versa. As a result, the structure can move (vibrate) or deform. A good understanding of this problem can help to design the system in term of safety, stability and efficiency.This project aims to optimize and test the Unicorn FSI solver from the FEniCS project [1] to simulate the interaction of fluid and structure in an experiment, which was carried out at Vattenfall Research and Development. The target is to improve the Unicorn FSI solver to cope with a real industrial problem.

This master thesis was a subtask of a project called EMIR-1. The goal with the thesis was tobuild a system for particulate mass measurements in one of the engine test cells at KTH. Theparticulate mass measurements are planned to be measured with a TEOM.The exhaust gases must first be diluted with air before the sample is sent to the TEOM.Therefore an ejector diluter for this matter also was designed and evaluated in the thesis.Emissions measurements have been done both with and without dilution to determine thedilution ratio. Tests have been done for different speeds and loads.Problems with stability of the dilution ratio have been an issue throughout the process andpressure pulsations in the exhaust pipe are believed to be the cause. More tests have to be done tomake sure that this is the problem.One idea is to make the inner diameter of the diluter nozzle smaller and see if it changes thedilution ratio stability.

AbstractAuthor: Ellinor Carlsson and Renate HöjdTitle: "When you can make a difference and when you can´t" the power relation between psychiatricdisability social worker and client [translated title]Supervisor: Eva SkogmanAssessor: Norma MontesinoOne branch of the social works field of research is the relation between social worker andclient. Research has shown that the power and inequality in the relation between helper andperson being helped is needed for the helper to provide help. Power is often mentioned undernegative circumstances such as social workers abuse of their power position, violating theperson being helped. However, Michel Foucault suggests that power is something neutral thatexists in every social interaction. The negative aspects of power are effects of the parties notreaching agreement.

The purpose of this project was to study how the interference between two antennas in a MIMO system affects the linearity of the power amplifiers powering the antennas. For the MIMO system, two power amplifiers and twoantennas were constructed and designed using the software ADS and a software defined radio was constructed using the platform USRP and the software LabVIEW. The result was that the interference between the antennas affectsthe linearity of the power amplifiers powering the antennas adversely and a reasonable theory was that the interaction decreases inversely proportional tothe square of the distance..