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 master thesis has been performed at Vattenfall Power Consultant in Gothenburg and Trollhättan for Vattenfall Vattenkraft. In this report vacuum circuit breaker in small-scale hydropower stations with the rated power 4 MVA and below has been studied. Models of the stations are modeled and analyzed in PSCAD/EMTDC to study the high voltage transients that are created after current chopping with vacuum circuit breaker. Vacuum circuit breaker may chop the current before it reaches zero value, which means that high voltage transients can be created. The equipment of the stations can be destroyed by high voltage transients.The purpose of this thesis is to examine the use of vacuum circuit breaker in small-scale hydropower stations and the risk for high voltage transients from current chopping.According to the results there is a risk of high voltage transients after current chopping with small synchronous generators in stations with the operating voltages 0.4 kV and 3.6 kV.

The aim and goal of this work has been to design and implement a voltage reference network for a 12-bit PSAADC, Parallell Successive Analog to Digital Converter. A chip containing the design has been sent away for fabrication. Because of the long processing time, no measurement data are presented. The main specifications for the voltage reference generator is to generate stable reference voltages with low noise and a good PSRR. Efforts has also been made to minimize the power consumption..

Microproduction, also called distributed generation, is something that has become more and more popular in the electric grid. Microproduction can however lead to unacceptable performance if several units are installed in the same low voltage network. It is therefore good to know a limit where the performance of the low voltage network becomes unacceptable based on given parameters. This limit is usually called hosting capacity.In this report the hosting capacity with respect to voltage and current have been studied in three low voltage networks which are located in Falu Elnäts concession area. This has been done by simulations in a GIS-program where critical times of the grid have been simulated.

Minimizing power consumption is a critical part of many embedded design projects. Thechallenge is to limit the power consumption of the system and at the same time providesatisfactory service to the user. With regards to microprocessors, the main way of limiting powerconsumption during program execution is to adjust the frequency and the voltage at which theprocessor operates.To enable the implementation of real-time scheduling with support for dynamic voltage andfrequency scaling, an exhaustive study of the Freescale i.MX31 embedded microprocessor isperformed. Specifically, the power consumption relationship to all relevant frequency andvoltage settings is investigated. In addition, to enable frequency and voltage scaling in a real-timeenvironment, a complete timing analysis of proposed voltage and frequency scaling methods isperformed and their suitability for use in real-time systems is evaluated.To integrate voltage and frequency scaling capability into OSE RTOS, a software module hasbeen developed for this operating system.

May 2010 a project called drop-in sports was started to get boys and girlsin the ages of 13-20 more physically active and keep them away from  committing crime. With the slogan ?come as you are, whenever you want and do what you want for free ? spontaneous sports was organized. To evaluate the project a research of the activity was carried out, where two of the objectives were to investigate how responsibility and empowerment is taken. Twelve hours of observations studies were used to collect data about leadership decision-making and democratic values in forms of respect, everybody?s right to play and influence.

Vi har med denna studie undersökt vilka vägledningsmodeller och metoder som vägledare använder i drop in- samtalet, samt deras inställning till detta. Den metod vi använder oss av i studien är semikvalitativa intervjuer tillsammans med en intervjuguide som bas med frågor uppdelade i teman. Dessa teman är modeller, metoder och inställningar. De vägledningsmodeller som vägledarna i studien använder sig mest av och som ligger som en grund för deras arbete är Gerard Egans modell ?The Skilled Helper?.

The dissertation deals with an account of actual problem, which can arise within EMC and power quality. The cause of power interruption and what can be done to minimise the power interruption is discussed. It also includes a definition of planning levels and which factors one needs to have control over to carry out a possible planning strategy and how the local distributions net could be more secure. The electrical net could be secure but no system can be free from interruption.The dissertation examines two distribution transformers: GLA40T1 (Glansås) and T399 in Tranås Energy which don?t have regulators.

The voltage level in the power grid varies due to variations in load and production. Normally these variations are manageable, but they may be excessively large during a disturbance. If the voltage is too high it may damage the equipment in the grid and too low voltages may cause problems like voltage instability. The magnitude of the voltage variation depends on the short circuit power capacity of the point of interest.This problem may become lore prominent due to automatic voltage regulation that acts on shunt reactors and shunt capacitors. When the shunt reactor is connected or disconnected to the grid it may cause such large changes in the voltage that the shunt reactor starts hunting.

This report is a Master?s Thesis performed by Andreas Adolfsson and David Jacobsson atChalmers University of Technology. The purpose of this master?s thesis is to evaluate anew method for load-shedding, the voltage controlled underfrequency load-sheddingdeveloped by ABB. This report presents a comparison between conventionalunderfrequency load-shedding and this new method for load-shedding.

Vi har med denna studie undersökt vilka vägledningsmodeller och metoder som vägledare använder i drop in- samtalet, samt deras inställning till detta. Den metod vi använder oss av i studien är semikvalitativa intervjuer tillsammans med en intervjuguide som bas med frågor uppdelade i teman. Dessa teman är modeller, metoder och inställningar. De vägledningsmodeller som vägledarna i studien använder sig mest av och som ligger som en grund för deras arbete är Gerard Egans modell ?The Skilled Helper?.

 The aim of this paper was to investigate how many students studying Swesdish as a foreign language, at secondary school level, in Tierps kommun, that have dropped out and their reasons for doing so. The reason for this is the report from Skolverket, stating that the rate of drop outs at this level is very high. To investigate this, a quantitative method was used. A questionnaire was sent out to all the students that dropped out 2005-2008. The result showed that the two main reasons for leaving their studies were that the individuals had found a job or thought the studies were too hard. The research also showed that the majority of the students had not been in contact with Career counseller prior to ending their studies. We came to the conclusion that there might be a need for developing the teaching and to work out routines for guidance at drop out situations.

Compressed air is a low efficiency media, and is thus very expensive to produce. This thesis work began by mind mapping how to create savings on the compressed air system at Billerud Skärblacka AB. Certain issues have been chosen for further studies.In order to identify the consumption of compressed air at PM 8 and 9, several measurements were made. At PM 8 there were not found any pressure drop, only large pressure variations for short periods of time. The causes of these pressure variations were not established.

System Andersson AB is a company located in Jönköping that works with developing computer systems for the mechanical engineering industry. As of today, when this report is written, the company is working on the development of a new Manufacturing Planning and Control (MPC) system. This new system aims to create not only a user friendly interface but also a modern, stylish interface. To achieve this, the company has decided to work with a, for them, new application framework; Windows Presentation Foundation (WPF).System Andersson is well known for developing systems for different kinds of touch screens, this project is no exception. For this new user interface the company wishes to implement different types of Drag&Drop functionality.

On a request from the water sewage plant Gryaab in Gothenburg a power quality survey was performed. The voltages and currents have continuously been sampled in the incoming 10 kV substation HSP01 from April-August 2008. Power quality measurements were also performed in Gryaabs other 10 kV substation HSP04 fed from HSP01 and at the terminals of the induction motor IN_PU4040 of 1.3 MW which controls one of the four large inflow pumps to the plant. The reason for the latter measurement was due to registered negative transients each time the motor was connected to the grid. The cause of the transients could be explained by the coupling in the substation, the ageing of the motor which could result in damage of the bearings or resonance in the motor circuit which amplifies high frequency harmonics.