Good power quality is not only determined by uninterruptable power supply, voltage deviations also affect the function of the network and the equipment connected. Electromagnetic disturbances as flicker, harmonics, interharmonics and unbalance are decreasing the power quality. How are the measurement methods and restrictions stated, to keep the voltagedeviations within reasonable limits and thereby maintaining the networkfunction? Lillgrund wind farm has power quality restrictions set by E.ON Elnät to fulfil in the connection point to the subtransmission network. In addition isa fault ride through requirement set by SVK. All equipment connected tothe network are introducing voltage changes, which can be measured at the point of connection. The scope of the thesis has been to explicitly determine Lillgrund‟s emissions. Three-phase voltage and current measurements have been performed, with measurement systems comprising different bandwidth, to analyse the power quality parameters.Comparisons between standard documentation and technical specifications have been made in order to precise what is considered as good power quality and how it can be measured accurately.

Experimental research has been completed using a custom designed and built 4m diameter wind turbine in a university operated wind facility. The primary goals of turbine testing were to determine the power production of the turbine and to apply the particle image velocimetry (PIV) technique to produce flow visualization images and velocity vector maps near the tip of a blade. These tests were completed over a wide range of wind speeds and turbine blade rotational speeds. This testing was also designed to be a preliminary study of the potential for future research using the turbine apparatus and to outline it's limitations. The goals and results of other large scale turbine tests are also briefly discussed with a comparison outlining the unique aspects of the experiment outlined in this thesis. Power production tests were completed covering a range of mean wind speeds, 6.4 m/s to 11.1 m/s nominal, and rotational rates, 40 rpm to 220 rpm. This testing allowed the total power produced by the blades to be determined as a function of input wind speed, as traditionally found in power curves for commercial turbines. The coefficient of power, Cp, was determined as a function of the tip speed ratio which gave insight into the peak power production of the experimental turbine. It was found, as expected, that the largest power production occurred at the highest input wind speed, 11.1 m/s, and reached a mean value of 3080 W at a rotational rate of 220 rpm. Peak Cp was also found, as a function of the tip speed ratio, to approach 0.4 at the maximum measurable tip speed ratio of 8. Blade element momentum (BEM) theory was also implemented as an aerodynamic power and force prediction tool for the given turbine apparatus. Comparisons between the predictions and experimental results were made with a focus on the Cp power curve to verify the accuracy of the initial model. Although the initial predictions, based on lift and drag curves found in Abbot and Von Doenhoff (1959), were similar to experimental results at high tip speed ratios an extrapolation of the data given by Hoffman et al. (1996) was found to more closely match the experimental results over the full range of tip speed ratios. Finally PIV was used to produce flow visualization images and corresponding velocity maps of the chord-wise air flow over an area at a radius ratio of 0.9, near the tip of a blade. This technique provided insight into the flow over a blade at three different tip speed ratios, 4, 6 and 8, over a range of wind speeds and rotational rates. A discussion of the unique aspects and challenges encountered using the PIV technique is presented including: measuring an unbounded external flow on a rotating object and the turbulence in the free stream affecting the uniform seeding and stability of the flow.

Bulk electric system reliability analysis is an important activity in both vertically integrated and unbundled electric power utilities. Competition and uncertainty in the new deregulated electric utility industry are serious concerns. New planning criteria with broader engineering consideration of transmission access and consistent risk assessment must be explicitly addressed. Modern developments in high speed computation facilities now permit the realistic utilization of sequential Monte Carlo simulation technique in practical bulk electric system reliability assessment resulting in a more complete understanding of bulk electric system risks and associated uncertainties. Two significant advantages when utilizing sequential simulation are the ability to obtain accurate frequency and duration indices, and the opportunity to synthesize reliability index probability distributions which describe the annual index variability. <p>This research work introduces the concept of applying reliability index probability distributions to assess bulk electric system risk. Bulk electric system reliability performance index probability distributions are used as integral elements in a performance based regulation (PBR) mechanism. An appreciation of the annual variability of the reliability performance indices can assist power engineers and risk managers to manage and control future potential risks under a PBR reward/penalty structure. There is growing interest in combining deterministic considerations with probabilistic assessment in order to evaluate the system well-being of bulk electric systems and to evaluate the likelihood, not only of entering a complete failure state, but also the likelihood of being very close to trouble. The system well-being concept presented in this thesis is a probabilistic framework that incorporates the accepted deterministic N-1 security criterion, and provides valuable information on what the degree of the system vulnerability might be under a particular system condition using a quantitative interpretation of the degree of system security and insecurity. An overall reliability analysis framework considering both adequacy and security perspectives is proposed using system well-being analysis and traditional adequacy assessment. The system planning process using combined adequacy and security considerations offers an additional reliability-based dimension. Sequential Monte Carlo simulation is also ideally suited to the analysis of intermittent generating resources such as wind energy conversion systems (WECS) as its framework can incorporate the chronological characteristics of wind. The reliability impacts of wind power in a bulk electric system are examined in this thesis. Transmission reinforcement planning associated with large-scale WECS and the utilization of reliability cost/worth analysis in the examination of reinforcement alternatives are also illustrated.

Electric power systems are experiencing dramatic changes with respect to structure, operation and regulation and are facing increasing pressure due to environmental and societal constraints. Bulk electric system reliability is an important consideration in power system planning, design and operation particularly in the new competitive environment. A wide range of methods have been developed to perform bulk electric system reliability evaluation. Theoretically, sequential Monte Carlo simulation can include all aspects and contingencies in a power system and can be used to produce an informative set of reliability indices. It has become a practical and viable tool for large system reliability assessment technique due to the development of computing power and is used in the studies described in this thesis. The well-being approach used in this research provides the opportunity to integrate an accepted deterministic criterion into a probabilistic framework. This research work includes the investigation of important factors that impact bulk electric system adequacy evaluation and security constrained adequacy assessment using the well-being analysis framework.<p> Load forecast uncertainty is an important consideration in an electrical power system. This research includes load forecast uncertainty considerations in bulk electric system reliability assessment and the effects on system, load point and well-being indices and reliability index probability distributions are examined. There has been increasing worldwide interest in the utilization of wind power as a renewable energy source over the last two decades due to enhanced public awareness of the environment. Increasing penetration of wind power has significant impacts on power system reliability, and security analyses become more uncertain due to the unpredictable nature of wind power. The effects of wind power additions in generating and bulk electric system reliability assessment considering site wind speed correlations and the interactive effects of wind power and load forecast uncertainty on system reliability are examined. The concept of the security cost associated with operating in the marginal state in the well-being framework is incorporated in the economic analyses associated with system expansion planning including wind power and load forecast uncertainty. Overall reliability cost/worth analyses including security cost concepts are applied to select an optimal wind power injection strategy in a bulk electric system. The effects of the various demand side management measures on system reliability are illustrated using the system, load point, and well-being indices, and the reliability index probability distributions. The reliability effects of demand side management procedures in a bulk electric system including wind power and load forecast uncertainty considerations are also investigated. The system reliability effects due to specific demand side management programs are quantified and examined in terms of their reliability benefits.

A challenge related to the expansion of wind power concerns how wind power developers can foster a good relationship with local communities. Building on research on social acceptance for wind power, this thesis addresses two identified gaps. The main focus is a theoretical gap, where previous research is criticized for assuming perfectly flexible organizations when suggesting how social acceptance can be enhanced. Also, an empirical gap is addressed by studying India, a different socio-economic and socio-cultural context compared to western contexts, which previous research has focused on. The aim is to study how management’s stakeholder prioritization affects community acceptance through a qualitative case study of a large Indian wind power developer with data from semi-structured interviews with senior management and internal company reports. The results show that managers’ stakeholder prioritizations and organizational constraints affect community acceptance and that the factors that enhance community acceptance has to be adapted to the context.

Vårt syfte med denna studie är att undersöka de kontroverser som uppstått vid vindkraftsetableringar på Västkusten. Detta syfte innefattar frågeställningar om vilka argument och aktörer som är inblandade och vad som formar en aktörs åsikter. Anledningen till att vi valde detta område var på grund av ett förslag vi fick från en konsult inom området. När vi studerat ämnet närmare insåg vi att det existerar kontroverser kring de olika etableringar som skett och även runt de som endast är i planeringsstadiet. Dessutom insåg vi att det inte fanns mycket aktuell forskning inom området. Studien är baserad på material som har insamlats i form av samrådsredogörelser, artiklar, insändare och fyra utförda intervjuer. Tolkning av materialet har skett utifrån en diskursanalys som gett resultat i form av tre olika diskurser inom kontroversen; Miljödiskursen, Lekmannadiskursen och den Ekonomiska diskursen. Det som resultat och analys visar är att aktörer som representerar motståndarna främst är privatpersoner. Förespråkarna är vanligtvis kommuner, företag och andra parter som vill etablera vindkraft. Argumenten som läggs fram av motståndarna är mer lokalt förankrade medan förespråkarna talar om allmännytta och globala intressen. Motståndarna vill generellt sett inte se någon förändring i närmiljön då de anser denna som värdefull natur. Samma natur som förespråkarna istället anser kunna vara vacker även efter en vindkraftsetablering. Våra slutsatser är att kontroversen är uppdelad i två framträdande parter, för och emot. De som är neutrala i frågan har inte kunnat urskiljas i materialet. Förespråkarna och motståndarna tenderar att peka på en ovilja att förstå varandra och en ständig debatt kretsar kring vilka kunskaper och argument som anses vara legitima. Böhler (1998) talar om en orörd natur som en symbol för framtidstro. Inom denna finner vi en paradox då motståndarna argumenterar för en orörd natur, samtidigt som de vill bruka och vistas inom denna. / Our purpose with this study is to investigate the controversy that are generated when construction of wind power are planned on the Swedish west coast. This purpose includes questions about the arguments and the actors involved, and what shapes an actor’s opinions.   The reason why we chose this area were because of a proposal we received from a consultant in the field. When we later on, studied the subject, we realized that there are several cases of conflicts surrounding various establishments of wind power that have taken place. We also found conflicts about those that are in the planning stage. In addition, we realized that there was not much current research in the area.   The study is based upon materials that have been collected in the form of articles, consolation reports, opinion pieces and four interviews. Interpretation of the material has been based on a discourse analysis which results in three different discourses in the controversy; The environmental discourse, the lay discourse and the economic discourse. The results and analysis show that the actors representing the opponents are mainly private individuals. Proponents are usually municipalities, companies and other actors wishing to establish wind power. The arguments presented by the opponents are more locally based, while proponents talk about public benefit and global interests. Opponents would generally not want to see any change in the living area because they see this as a valuable piece of nature. The same nature that the proponents instead consider to be beautiful even after wind plants has been built.   Our conclusions are that the controversy is divided into two major parties, for and against. We have not been able to identify those who are neutral about the subject. Proponents and opponents tend to point to an unwillingness to understand one another and an ongoing debate revolves around what kind of knowledge and arguments are considered to be legitimate. Böhler (1998) speaks if an untouched nature as a symbol of hope for the future. Within this, we find a paradox when the opponents are arguing for unspoiled nature, while they want to use it for recreation and to stay within it.

The wind power increase of Gotland as well as other parts of Sweden during the last ten year period has meant that this renewable energy source has increased its share over other fossil sources. The year of 2011 became the first when the wind power produced more energy than an average nuclear reactor. Now that wind power is in an expansive phase, the land issue will be of great interest. Land with good wind resources will be of interest to wind energy developers.  The problems that this essay is based on are; how can landowners altering the economic conditions at a wind power establishment? What opportunities and obstacles exist for landowners who choose to set up wind power on their land? The purpose of this essay is to highlight the economic conditions that exist for landowners for the establishment of wind farms, with regard to compensation for the leasing and return on invested capital. The authors will also clarify the difficulties and opportunities arising from the process at an imaginary wind power establishment, which have emerged through interviews and research articles. The primary sources consist of interviews with actors for a planned wind farm in southeast Gotland, as well as representatives of a trade association of companies working with wind power. Interviews were also made with a bank, where the experience in question funding for wind energy has been important for our problem as well with a wind turbine manufacturer for real facts about wind turbines.  Landowner’s interest in wind energy as a long term investment has in Lau on Gotland resulted in a project where local landowners have chosen to form a joint company to invest in a wind farm, with the goal that the park generally will be owned by local residents in the parish. Conclusions to be drawn from this study is that landowners who form a joint company, in this case Lau Wind AB will open an opportunity for landowners to take a larger share of the ownership and profits as wind power turbines on their land supplies. But also for locals who have opportunity to become owners of the wind through the purchase of shares in wind farm.

On a global scale, the deployment of wind power plants is soaring. However, the availability of their construction materials could be a potential bottleneck, a problem rarely discussed in literature so far. Rare earth elements represent the most critical materials in terms of high economic importance, supply risk and environmental risk. This study therefore provides a market analysis of rare earths, ascertaining that geological scarcity is not the main problem. Instead, four kinds of market failure are identified: market power, co-production, by-production and negative externalities. Altogether, the market for rare earth metals is in a state of severe disequilibrium. Subsequently, an estimate of future rare earth demand patterns based on the wind power industry by 2050 reveals that the current level of supply is unlikely to be sufficient in the long run. To allow for a more elaborate analysis, two options of including a rare earth side condition in an integrated assessment model are finally suggested.

The objective of this thesis is to investigate the transient response and optimal economic dispatch of an isolated power system with wind generators. Different types of wind turbines and the classification of Stability are introduced. Then, the process of Transient stability analysis and the concept of Genetic Algorithms are given for explanation. In this thesis, the practical power system of Kinmen is selected for case study. The disturbances introduced by gusting wind and N-1 system contingency are considered in the transient stability analysis. Furthermore, in order to obtain both accuracy and feasibility of the Optimal power dispatch by using Real-parameter Genetic Algorithms, the simulation results should be tested for the restrictions and requirements of the actual operation.

Demand is emerging for offshore wind power plant (WPP) that often has favorable capacity factor and high capacity value as compared with onshore wind farms. There are many challenges regarding power losses, economics, protection system and reliability of the wind farm. Collection system design decisions play an essential role to efficient operation of the WPP. Wind generators also have to be able to cope with grid disturbances. Low voltage ride-through (LVRT) capability of wind turbines requires generator units remain in operation for severe voltage drops during ¡@grid system faults, and be able to withstand depressed voltage for a few seconds in a recovery period. Technical requirements set out in grid codes for off shore wind farm normally relate to different connection points. A rigor LVRT requirement would increase the overall investment costs of the wind farm. In most offshore wind farm projects, radial collector systems connecting a number of wind turbines and terminated at the offshore platform have served well the requirements for an economical design. However, due to the lack of redundancy, its reliability is poor. To improve the reliability of the collector system, the inclusion of a cable section that interconnects the remote ends of two adjacent radial feeders has been proposed. The transmission system of a wind farm takes the power generated and sends it to shore. Medium voltage AC transmission is the simplest one, just gathering the cables from the collector system and taking them together until they reach the point of common coupling (PCC).Through wind farm dynamic simulations by using DIgSIENT package, this thesis demonstrates that the ride through capability which occur at the particular wind parks with different collector system topology are greater than those which the wind turbines are capable of riding through, i.e., LVRT curves of different wind farm collection system designs of an offshore WPP and a single wind generator are different. This can be exploited to reduce the cost in complying with LVRT requirement of offshore WPP.