Synchrone Messungen der Windgeschwindigkeit und die Leistung von Windkraftanlagen dienen der Ermittlung der Kennlinien der Anlagen. Die existierenden Vorschriften zur Vermessung enthalten bezüglich der Strömungseigenschaften des Windes nahezu keine Spezifikationen. Diese sind jedoch notwendig, um die erreichbare Genauigkeit und Repräsentativität der vermessenen Kennlinie zu quantifizieren. Messungen am Standort der AEOLUS II-Anlage in Wilhelmshaven dienten dazu, bei einer Anlagenvermessung die Eigenschaften der Strömung und die Kennlinie gemeinsam zu untersuchen. Es wurde gefunden, daß die Strömungseigenschaften wie die vertikale Windscherung, die Winddrehung über der Höhe, die turbulenten Schwankungen der Windgeschwindigkeit und der Windrichtung die Leistung von Windenergieanlagen bei gleicher mittlerer Windgeschwindigkeit erheblich verändern. Dabei wirken sowohl Standorteigenschaften als auch die Witterung auf die Ergebnisse der Vermessung. Am gleichen Standort können in anisotropem Gelände die Werte der Kennlinie auch bei mehrmonatigen Vermessungen wegen der Variabilität der Windrichtung Unterschiede von mehr als 10 % aufweisen. Der größte Einzeleffekt wird von der vertikalen Windscherung verursacht, die Wirkung der Drehung des mittleren Windvektors über der Rotorfläche ergab sich als kleinerer Effekt. Die Wirkung der turbulenten Schwankungen von Geschwindigkeit und Richtung weisen meist unterschiedliche Vorzeichen auf, so daß die Rolle dieser Schwankungen insgesamt meist klein bleibt. Die Vermessung einer Kennlinie mit einer kleineren systematischen Abweichung von im Mittel weniger als etwa 5 bis 10 % erfordert eine genaue Strömungsspezifikation sowohl für den Vermessungs- als für den Betriebsstandort, die bisher nicht in hinreichendem Maße in den entsprechenden Richtlinien und Vorschriften enthalten sind. / Power curves ofwind energy convetras need synchronous measurements of wind and power. The existing specification on the wind measurements are rather poor, however necessary. AEOLUS II-measurments and the wind measurments served to quantify the role of the different atmospheric parameters. Thus it was possible to define the influence on the power output of the machine as a function of the vertical wind shear, the wind veer with height, the turbulent fluctuations with the average wind speed being constant. As a consequence site properties and weather conditions both influence the measurements of the power curve. As a major result it was found that these factors may alter the power curve by as much as 10 %. The largest single effect is produced the effects of the vertical wind shear, The turbulent fluctuations are somewhat smaller in their effect, because speed and direction effects tend to compensate each other. lt may be concluded that a highly accurate power curve - meaning errors to be less than 10 % - requires a fully specified set of weather and site parameters.

Additive manufacturing (AM), also known as 3D-printing is an automated manufacturing process in which the component is built layer upon layer from a predefined 3D computer model. In contrast to conventional manufacturing processes where a vast volume of material is wasted due to machining, AM only uses the material that the component consists of. In addition to material savings, the method has a number of potential benefits. Two of these are (1) a large design freedom which enables the production of complex geometries and (2) a reduced compexity in supply chain as parts can be printed on-demand rather than be kept in stock. This master thesis has been performed at Vattenfall Wind Power and aims to investigate the feasibility to reproduce and/or to refurbish one or two spare parts on a wind turbine by AM and if it can introduce any practical benefits. Components with a high failure rate and/or with an suitible design for AM have been investigated. A rotating union or fluid rotary joint (FRJ) was selected for further analysis. A comprehensive background study has been conducted. A current status of metal AM is described as well as a comparison between conventional and additive processes. Furthermore, current and future applications for AM witihin the wind turbine industry are presented. The mehodology "reverse engineering", main components in a wind power plant including the fluid rotary joint as well as fluid dynamics are also treated in the background study. As a part of the process, a fluid rotary joint with worse historical failure data was disassembled and examined. In order to find other design solutions that contributes to a better and more reliable operation, another better performing fluid roraty joint was investigated. Since detail drawings and material information are missing for the examined units, reverse engineering has been carried out to gather details of the designs. A concept for the first unit has been developed, in which improved design solutions has been introduced and a number of changes have been implemented in order to minimize material consumption and to adapt the design for AM. The concept has been evaluated by the use of numerical methods. Costs and build time have also been estimated for the developed concept. This project has illustated that it is feasable to manufacture spare parts by the use of AM. The developed concept demonstrates several improvements that are not possible to achieve with conventional manufacturing processes. Nevertheless, a number of limitations such as insufficient build volume, costs as well as time cosuming engineering effort and post-proccessing methods are present for AM. These restrictions, in combination with lack of 3D-models, limits the possibility to make use of the technology. However, the future looks bright, if the technology continues to develop and if subcontractors are willing to adapt to AM it will probably have a major breakthrough within the windpower industry. / Additiv tillverkning, "additive manufacturing" (AM) eller 3D-printing är en automatiserad tillverkningsmetod där komponenten byggs lager för lager från en fördefinierad 3D datormodell. Till skillnad från konventionella tillverkningsmetoder där en stor mängd material ofta bearbetas bort, använder AM nästintill endast det material som komponenten består utav. Förutom materialbesparingar, har metoden ett flertal andra potentiella fördelar. Två av dessa är (1) en stor designfrihet vilket möjliggör produktion av komplexa geometrier och (2) en möjlighet till en förenklad logistikkedja eftersom komponenter kan tillverkas vid behov istället för att lagerföras. Detta examensarbete har utförts på Vattenfall Vindkraft och har till syfte att undersöka om det är möjligt att tillverka och/eller reparera en eller två reservdelar genom AM och om det i så fall kan införa några praktiska fördelar. En kartläggning av komponenter med hög felfrekvens och/eller som kan vara lämpade för AM har genomförts. Av dessa har en roterande oljekoppling även kallad roterskarv valts ut för vidare analys. En omfattande bakgrundsstudie har utförts. En nulägesorientering inom området AM för metaller redogörs, här redovisas även en generell jämförelse mellan konventionella och additiva tillverkningsmetoder. Vidare behandlas aktuella och framtida användningsområden för AM inom vindkraftsindustrin. I bakgrundsstudien behandlas också arbetssättet "reverse engineering", huvudkomponenter i ett vindkraftsverk inklusive roterskarven samt flödesdynamik. Under arbetets gång har en roterskarv med sämre driftshistorik undersökts. I syfte att finna andra konstruktionslösningar som bidrar till en säkrare drift har en bättre presenterande enhet från en annan tillverkare granskats. Då viss detaljteknisk data och konstruktionsunderlag saknas för de undersökta enheterna har "reverse engineering" tillämpats. Ett koncept har sedan utvecklats för den första enheten där förbättrade konstruktionslösningar har introducerats samtidigt som en rad konstruktionsförändringar har gjorts i syfte att minimera materialåtgången och samtidigt anpassa enheten för AM. Konceptet har sedan evaluerats med hjälp av numeriska beräkningsmetoder. För det givna konceptet har även kostnad och byggtid uppskattats. Arbetet visar på att det är möjligt att ta fram reservdelar till vindkraftverk med hjälp av AM. Det framtagna konceptet visar på ett flertal förbättringar som inte kan uppnås med konventionella tillverkningsmetoder. Emellertid finns det en rad begränsningar såsom otillräcklig byggvolym, kostnader och tidskrävande ingenjörsmässigt arbete och efterbehandlingsmetoder. Dessa förbehåll i kombination med avsaknad av 3D-modeller begränsar möjligheterna att nyttja tekniken i dagsläget. Framtiden ser dock ljus ut, om tekniken fortsätter att utvecklas samtidigt som underleverantörer är villiga att nyttja denna teknik kan AM få ett stort genombrott i vindkraftsindustrin.

Ištirti mažos galios horizontaliosios ašies vėjo jėgainės energetines charakteristikas ir nustatyti efektyvumo didinimo galimybes. / Survey energy characteristics of little capacity horizontal axis wind power plant and identify efficiency increase potential.

This thesis deals with methodology for creating innovative concepts and their solving. More precisely, TIPS methodology „Theory of inventive problem solving“. This thesis is divided into four parts. In the first part, this methodology and its five basic tools are introduced. The second part provides introduction of software Goldfire Inovator including the tools which could be useful for students working on their projects. Third part demonstrates TIPS methodology on the innovation of wind power plant supported by software Goldfire Inovator. The fourth part evaluates advantages and contributions of TIPS methodology for education and practice.

Bei der Errichtung von Windenergieanlagen in Mittelgebirgsregionen ist darauf zu achten, daß an windexponierten Standorten die Gefahr einer Vereisung der Rotorblätter besteht. Es wurden klimatologische Daten im Bereich der Mittelgebirge ausgewertet und daraus eine Karte erarbeitet, in der die jährliche mittlere Häufigkeit der Tage mit Eisablagerungen dargestellt ist. / With the installation of wind turbines in low mountain areas the hazard of ice accretions on rotor blades at windy places must be considered. Interpreting climatological datas of the low mountain areas of S. E. Germany a map has been produced which shows the annual frequencies of days ice accretions on structures occurs.

This thesis presents a comprehensive procedure to study sub-synchronous interactions in wind integrated power systems effectively and efficiently. The proposed procedure involves a screening phase and a detailed analysis phase. The screening is performed using a frequency scan and the detailed analysis is performed using small signal stability analysis. To facilitate the small signal analysis, a detailed linearized model of a Type 3 wind power plant is presented in this thesis. The model presented includes the generator, a three-mass drive train model, rotor and grid side converter controller models, converter transformer model and the pitch controller model. To accurately capture the effects of sub-synchronous interactions, the ac network is modelled using dynamic phasors. It is shown that using the proposed procedure, the sub-synchronous interaction between a Type 3 wind power plant and a series compensated line is due to an electrical resonance between the wind power plant generator and the series capacitor. It is also shown that this interaction is highly controllable through the rotor side converter current controllers. This fact will be proven by studying the sub-synchronous interactions in a single machine power system as well as in multi machine power systems. This thesis also presents a sub-synchronous interaction mitigation method using network devices. The performance of an SVC and a STATCOM is evaluated in this thesis. A small signal stability analysis based method will be used to design a sub-synchronous damping controller. A method will be presented to estimate the damping controller parameters systematically to obtain the desired performance using small signal stability analysis results. Furthermore, it will be shown that by strongly controlling the voltage of the point of common coupling, the damping of the oscillations produced by the sub-synchronous interaction between the wind power plant and the series compensated line can be improved. Based on the findings of this research, the thesis proposes a number of recommendations to be adopted when studying the sub-synchronous interactions in wind integrated power systems. These recommendations will facilitate to do such studies effectively and pinpoint the root cause of the sub-synchronous interactions.

This thesis examines the design of supervisory controllers for windfarms of pitch-controlled wind turbines. The control objectives are the maximisation of the financial income from the generated electricity and the minimisation of the turbines' fatigue damage. The design exploits the wide variations in the ratio of financial income to fatigue damage which are found both spatially across windfarms and as a function of time. The supervisory control strategy makes use of the ability of pitch-controlled turbines to operate with variable power set points; a capability which is rarely exploited in practice. A windfarm simulation which has been developed for the purposes of testing supervisory controllers is described. It is shown that the simulation is a suitable test-bed for this application. Results are presented which demonstrate how the fatigue damage of a turbine's gearbox and structural components vary as functions of the mean wind-speed, turbulence intensity and power set point, both for isolated turbines and for turbines experiencing wake effects. A lifetime performance function is proposed and 'ideal' power set point curves are evaluated using a genetic search algorithm. It is shown that significant improvements in performance can be achieved if the operation of the turbines is altered to take account of variable electricity tariffs. A windfarm control strategy that splits the turbines into interacting and non-interacting categories is found to give good results. Using data generated by the simulation, it is shown that simple cost functions can be developed for non-interacting turbines which, when used in a controller, give performance that is close to the 'ideal'. A similar cost function is applied to a group of three interacting turbines, and it is found that substantial reductions in all measures of total annual fatigue damage are achieved for a small reduction in total annual financial income. The on-line implementation of windfarm supervisory controllers is discussed and the behaviour of a simple hill-climbing algorithm is examined using a simulated group of three interacting turbines.

Orientadores: Paulo de Barros Correia, Ieda Geriberto Hidalgo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-28T12:05:23Z (GMT). No. of bitstreams: 1 Barros_RegianeSilvade_D.pdf: 4190585 bytes, checksum: c320645bbd13fd28d572f5b9751d4ff7 (MD5) Previous issue date: 2015 / Resumo: Este trabalho propõe um modelo de despacho ótimo no horizonte diário de operação, que permite coordenar a operação entre uma usina eólica e uma usina hidrelétrica. Nessa abordagem, a usina eólica é despachada em primeira instância. Para suprir eventuais saídas forçadas que possam ocorrer na geração eólica, aloca-se um valor de reserva girante incremental na usina hidrelétrica usando o conceito de Value at Risk como métrica de risco da geração eólica. O modelo é formulado como um problema multiobjetivo que busca maximizar a geração de energia e minimizar o número de partidas e paradas da usina hidrelétrica. O acoplamento hidráulico é considerado através da meta diária de defluência da usina. O problema é solucionado em duas etapas. A primeira resolve 24 problemas estáticos, que representam o despacho horário da usina hidrelétrica, separadamente. Essa etapa emprega o Algoritmo Genético para otimizar a operação da usina em termos da geração de energia elétrica. A segunda etapa soluciona o problema dinâmico, ou seja, o despacho diário da usina. A natureza do problema dinâmico, correspondendo à obtenção de caminhos mínimos eficientes em termos de partidas e paradas, sugeriu o uso da técnica de Otimização por Colônia de Formigas. As restrições de reserva girante, meta de defluência, atendimento do contrato de demanda e limites operacionais das usinas são plenamente satisfeitas. A diferença entre os montantes de energia produzidos e contratados é liquidada no mercado de curto prazo e valorada ao preço de liquidação das diferenças. O modelo se mostrou adequado em termos de tempo computacional e em relação à qualidade das soluções obtidas / Abstract: This work proposes an optimal dispatch model in the daily horizon, which coordinates the operation of a wind farm and a hydroelectric plant. In this approach the wind farm is dispatched first. In order to provide eventual faults that may occur in the wind farm generation, an incremental spinning reserve is allocated in the hydroelectric plant using the concept of Value at Risk. The model is formulated as a multiobjective problem which seeks to maximize the energy generation and to minimize the number of start-ups and shut-downs of the hydroelectric plant. The plant¿s hydraulic coupling is considered through the daily released flow goal. The model is solved in two stages, the first one solves, separately, 24 static problems that represents the hourly dispatch of the hydroelectric plant. This stage employs Genetic Algorithm to optimize the operation of the hydroelectric plant in terms of electric energy generation. The second stage considers the dynamic problem, which is the plant¿s daily dispatch. The nature of the dynamic problem, which implies in obtaining efficient shortest paths in terms of start-ups and shut-downs, suggests the use of the Ant Colony Optimization. The spinning reserve, the released flow goal, the demand contract and the generating unit¿s operational limits are fully satisfied. The difference between the energy amounts produced and contracted are liquidated in the spot market and it is valuated with the settlement differences price. Regarding computational costs and solutions quality, the model suitability is shown / Doutorado / Planejamento de Sistemas Energeticos / Doutora em Planejamento de Sistemas Energéticos

The submitted diploma thesis describes particular types of European energetic exchanges, focuses in depth on principles market in Czech Republic and studies the price development on spot and futures markets. The main idea of this work is to focus on renewable energy sources (RES) and their influence on energetic markets. At first, operational and reliability properties of RES are explained and then their development support is analyzed. Last chapters focus on how the power grid is impacted by RES that are hardly predictable source with local production characteristic. There are also outlined problems originating from irregular production that are linked to a surplus of electric energy, but also on energy shortage caused by bad weather. These problems influence international commerce and reduce the capacity of cross-border profiles.

Climate change is mankind’s biggest challenge and scientists around the globe agree that civilization is pushing towards a breaking point. Renewable energy are alternatives that are capable to remove the need for fossil fuel. Wind power will play a vital role and has the possibility to confront the challenges that face the globe. In order for wind power to reach its full potential constructors need to take into account the distance between each wind power turbine, as it can cause energy loss and generate less electricity into the system. These energy losses decrease the potential of wind power and thus also for renewable as a whole. Energy losses that emerge within the space between wind power plants are named wake losses. Once the wind has passed the plant, a distance equal to seven rotor diameters is needed for the wind to regain its full force. By positioning the plants within the announced distance, the production of each plant decreases since downstream turbines are not able to generate a full effect.       This Bachelor thesis in Energy Engineering aims to analyse these wake losses for the wind power plant Skäppentorp, which is situated in Mönsterås County. The nearby wind power plant Brotorp is affecting Skäppentorps production and the authors of this degree project chose to present the wake losses as a percentage. A third wind power plant named Idhult functioned as a reference. Idhult is of course not affected before the positioning of Brotorp but neither after it, therefore the plant was used to ensure that weak winds were not ascribed to Brotorp but are a result of a weak wind year. The Bachelor thesis covered thus three wind power plants, Skäppentorp which interacts and is affected by Brotorp and Idhult which served as reference. The wake losses were calculated in Microsoft Excel and set against the software windPRO to validate the programmed produced losses for the same plant. Skäppentorp’s surrounding were divided into 12 sectors, where each sector covers an angle of 30 degrees. By doing so a full circle, 360 degrees, surrounding the plant was established. The wind speed and the production before respectively after Brotorp deployment was produced by using a nearby measuring post. Via an average production value for each sector, before and after Brotorp, a percentage wake loss was calculated. This was set against Idhult to sort away better respectively worse wind years. The period before covered the year 2012 until 2015 and the period after covered 2016 until 2018.  The result from Microsoft Excel indicates that sector four and sector nine were subjected to the highest percentage of losses. The results from the software windPRO however indicated the highest loss in sector four. Three sectors obtained the same percentage loss as windPRO while remaining values came out dissimilar. The distinction between some of the sectors may be caused by the positioning of some of the Brotorp turbines, where some are located on the borderline between sectors. This implies that some turbines affect two sectors when calculated with Microsoft Excel, which it does not when simulated with windPRO. The sum of all sections indicated that Brotorp turbines caused a wake loss of 3,8 %. This was compared to the simulation in windPRO which resulted in 5,7 %.