The majority of all power cuts that affects individuals and communities are caused by earth faults on the power transmission lines at 10kV and 20kV level [1]. If these power cuts could be eliminated, less disturbances and interrupts would lead to large amounts of money savings.Swedish Neutral has developed such a protection system. When an earth fault occurs power is injected into the neutral point of the transformer. The RCC (Residual Current Compensation) protection calculates a compensation current exactly 180 degrees out of phase to the fault current. Doing this, the voltage at the fault location becomes very close to zero, without affecting the power transmission.The protection system can only compensate automatically for the fundamental frequency (50Hz), and manually for the 3rd, 5th, 7th and 9th harmonics.

The aim of this report is to examine the possibilities to use network theories to perform vulnerability analysis on complex networks. The scoop of this work is also to improve the possibilities to chart, analyze and present the vulnerability in a power grid. In this report it has been, using power outage statistics, possible to verify, that network theories can be used to evaluate the vulnerability of an infrastructure network. However further studies to establish values on how vulnerable a network is are needed..

This master thesis is a study of the Swedish hydropower capacity to balance wind power. The Swedish government has decided that it should be possible to produce 30 TWh from wind power in the year 2020. The Swedish municipalities have to have plans for wind power plants with total yearly generation of 30 TWh. Wind power is an variable energy source that needs to be balanced by other energy sources. In Sweden the Swedish hydropower can be used for balancing a large scale introduction of wind power.

This thesis analyzes the expected profitability in land based wind power plants. The expected profitability is calculated on the basis of a wind power project in Vartofta, Falköping. The information required to calculate the expected outcome is then concentrated to this project, which is in this thesis called project Näs. In project Näs they plan to build three wind power plants, with each an effect of 2 MWh. These wind power plants are very capital intensive investments with a long and uncertain payback time.

Wind power is a growing energy sector in Sweden. However, it still represents only a small part of the total electricity production, about 0.7%. In order to create good conditions and to facilitate the establishment of wind power in Sweden, the government has for example, created a national centre for wind use. The objective has been to reach the governmental goal, which is an expansion of wind power by 10 TWh by year 2015 compared to the level in 2002. The Swedish electricity market was deregulated in 1996 which refers to the introduction of a competitive market in electricity production and trade.

In Lake Vänern, Sweden, there is an endemic population of Atlantic salmon (Salmo salar L.) that lives its entire life in fresh water. The salmon is hindered from migrating to its natural spawning sites in the northern part of the River Klarälven by nine hydro-electric power plants. None of the hydro-electric power plants have fishways so that salmon migrating upstream or downstream may pass. In the current situation, the upward migrating salmon are caught in a fish trap at the most downstream located power plant in Forshaga. From there, the salmon are driven in a truck, past eight power plants and released a few kilometers upstream of the eighth power plant at Edsforsen.

Transmission of reactive power is well known to cause active power losses. Thus, newcomponents who can help minimizing these expensive reactive power flows are ofgreat interest to the power distribution companies. ABB Corporate Research hasdeveloped the first electronic power breaker. One possible application for thisbreaker is transient-free switching of capacitor banks. This could prove a usefuldistribution voltage complement to the switch-sync technique, mainly applied to transmissionvoltage level.

Aim: The purpose of this study is to explore how the media through a certain discourse constructs a view of the labor market and the power relations between companies, unions and employees. The goal is to explore this through studying the media coverage of SAS? financial situation between September-December 2012 and our research question is the following: What view of the labor market and its power relations was constructed and reproduced by Swedish newspapers through their portrayal of SAS during September-December 2012?Method: This study analyses the findings with the help of questions based on theories of social constructivism, discourse, agenda-setting and power. A content and discourse analysis was compiled of 360 articles from five Swedish newspapers that addressed SAS and their situation from September-December 2012. The results of these analyses were further processed using power analysis and John Gaventa?s power cube.Results: In this study we conclude that the medial discourse constructs identities of the different actors and affect power relations between them, in favor of the company.

The purpose of this study was to examine how social work professionals view their professional role and how they think about the concept of social work. I also wanted to investigate what they believe characterize a professional social work. For the purposes of this study, I chose a qualitative approach in which I interviewed five people linked to the social work. The theories which I have assumed in the analysis of the results are power theory, organization theory and professional theory. The results of this study show that the respondents believe that a professional social work is performed by someone who has training and experience in the field.

The aim of this thesis is to form a theory of the green consumer power and to distinguish whether this phenomenon could indicate a movement toward the ecological citizenship. To do so, scientific theories regarding the responsibility of companies have been used, as well as the public choice theory, to link individuals as citizens to individuals as consumers. The motives of corporate environmental responsibility, along with consumers ability to bring pressure in different dimensions, are later drawn on as indicators applied to empirical information. The largest producer of ecological products in Sweden, Arla Foods, is employed as case study to explore if the green consumer power can and does exist. The ecological citizenship uses the ecological footprint, to define in what ways we can minimize our part of environmental degradation.The study seems to strengthen the theory, consumers do have a power to make companies go green and they tend to use it increasingly.

The purpose of this study has been to investigate advantages and problems with distributionsystem metering in substations. This report is a study in cooperation with Göteborg Energi.The analyses in this report are made for GENAB, a subsidiary company of Göteborg Energi.To analyse advantages and problems in advance is interesting information for GENAB. Theresult of the report could be based upon whether installation of metering in distributionsubstations will be implemented and in that case which kind of measurement that is relevant.The most relevant and strategic place to implement measurement is at the distributionsubstations on the secondary side (400V), this is due to the placement of the currenttransformers. The measurements in this study involve current, voltage, power, power factor,temperature, energy and power quality.Measuring instruments that are relevant to implement are intended to measure current,voltage, power, power factor, energy and, possibly, power quality in the same measuring unit.It is desirable to have a measuring instrument that measures both energy and power qualitybut since it is most often a cost question, it can be established that energy meters have a lowercost.Metering in distribution substations gives a better illustration of the power network. Thisresults in many advantages for GENAB.

Academic research concerning how to determine the power situation in a supply chain where an investment product supplier is involved did not exist. Therefore new models has been developed that analyses the power relations and maps out the power situation in a supply chain. In the future these models can be applied on similar cases by modifying the included parameters. The new models show that case company FAS should focus on the big producers of garbage bag which are Trioplast, Rullpack and Miljösäck. By strengthen the brand FAS can make more money in these relations.

This master thesis was made to validate hydropower models of a turbine governor,Kaplan turbine and a Francis turbine in the power system simulator ARISTO atSvenska Kraftnät. The validation was made in three steps. The first step was to makesure the models was implement correctly in the simulator. The second was tocompare the simulation results from the Kaplan turbine model to data from a realhydropower plant. The comparison was made to see how the models could generatesimulation result that was similar to the reference power station.

Wind power is one of the sources of renewable energy which has to be developed further in order to lessen our dependence on non renewable sources of energy. It's mainly oil and coal which have to be replaced by green energy. Wind power is already established in many countries, for example Germany, The United States of America and Denmark but it has to be continually developed and expanded to meet the needs of the growing energy consumption in the world. During the last few years many types of small wind turbines have appeared on the market. These small wind turbines are an alternative to the big wind turbines or power generators which demand huge sums of investment money.A new target group can now buy the small wind turbines in order to cover their own usage of electricity.

Fortum has in a pilot project installed metering equipment with wireless communication in secondary substations in Stockholm. So far, the collected data are used only in specific projects.This master thesis was carried out at Fortum Distribution AB in Stockholm during 2013. The purpose of this study is to simplify and enhance the use of data in for example network planning process, by giving suggestions on how data can be managed and giving examples of analyzes that collected data can be used for.The electricity meter which Fortum has installed is a EDMI-Mk10A which is set to measure max/average/min values with a one hour time resolution of the following parameters: voltage (per phase), current (per phase) andactive power and active and reactive energy.In order to analyze the collected data an analysis tool is required. During this thesis two customized tools in Microsoft Excel have been developed, one for sorting data and one for analyzing.One aim of the thesis is to show examples of what collected measurement data can be used for. This work shows an example of analysis of active power, power factor, voltage, occurrence of interrupts and the relationship between outdoor temperature and power.This master thesis has among others resulted in the following advice: Expand the number of secondary substations with measuring equipment.