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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Livscykelkostnader för vindkraft : En jämförelse av fallstudier / Life cycle costs for wind power : A comparison of case studies

Sjölander, Martin, Svensson, Anders January 2012 (has links)
I denna rapport har det utförts två fallstudier från två olika vindkraftsanläggningar och med hjälp av en utarbetad modell har livscykelkostnaderna jämförts för de två fallstudierna.Resultatet visade att livscykelkostnaden per producerad kWh sjunker allteftersom den installerade effekten blir högre.Kostnadsmodellen som utarbetats och tillämpats för resultaten har visat sig ha hög verifierbarhet då resultaten har varit jämförbara med litterära studier. / In this report, conducted two case studies from two wind farms and using an elaborate model, life cycle costs compared to the two case studies.The results showed that the lifecycle cost per kWh decreases as the installed power increases.Cost model as developed and applied to generate the reported results have been generated in the results that are comparable to literary studies.
72

WAKE EFFECT IMPACTS ON THE ENERGY PRODUCTION OF THREE WIND TURBINES IN CLOSE CONFIGURATION

HEKİM, MEHMET ÇAĞRI January 2015 (has links)
With the rapid expansion of offshore wind power capacity in the world in the last decade, innovative offshore solutions are designed in order to meet the upcoming power capacity installations. As in all other energy sectors, offshore wind power has certain conditions that have to be met to increase the efficacy of the outcome.In this thesis, wake effect impact on the production results of Hexicon AB’s innovative floating and rotating offshore wind power platform project with 3 turbines located in the southern part of Sweden are analyzed through the application of “Analytical wake models” and the “Actuator Disc method”, with the help of WindSim.The results of Analytical models and Actuator Disc method were found to be independent of one another. Even though analytical wake models did not find any wake effect impact among the turbines, the results can be considered as logical. However, the Actuator Disc method created unexpected results which might stem from the WindSim – AD combination. It is therefore recommended to further explore these scenarios with other (more) advanced simulation tools.
73

Understanding aquatic carbon loss from upland catchments in south west Scotland during land use change from commercial forest to wind farm

van Niekerk, Melanie January 2012 (has links)
High concentrations and fluxes of dissolved organic carbon (DOC) in fluvial systems are associated with the dark brown water colour familiar in many upland, peat-dominated areas and may indicate a depletion of the terrestrial carbon store. The removal of this colour can also be problematic and expensive for water companies as well as affecting the ecological functioning of the water body through factors such as reduced light penetration through the water column. Disturbance resulting from activities such as land use change can also enhance the loss of carbon and this may manifest itself in elevated concentrations and fluxes of DOC from aquatic systems. This thesis describes and explains patterns of change in DOC quantity and quality from the Crosswater, Crosswater of Luce and Tig catchments draining Arecleoch Forest, a peatland in south Ayrshire, Scotland, from 2008 to 2010. This time period incorporates the installation of a 60-turbine wind farm built and operated by Scottish Power Renewables (SPR). Water samples were collected from Arecleoch at different spatial scales ranging from catchments to soil pore water and temporal scales ranging from daily to seasonally. Concentrations of DOC were measured and fluxes estimated at the catchment scale. DOC concentrations from all three catchments exhibited the well-established seasonal pattern with maxima in late August/early September and minima seen in February/March. The Tig catchment experienced the greatest burden of disturbance from the wind farm development and returned the highest DOC concentrations and fluxes. The Crosswater catchment, used as a control site due to its isolation from wind farm activities, had higher DOC concentrations than the Crosswater of Luce throughout the monitoring period possibly due to a greater proportion of forest cover. ii DOC flux ranged from 35.0 g C m-2 yr-1 from the Crosswater of Luce catchment in 2008 to 55.0 g C m-2 yr-1 from the Crosswater in 2009. The Tig catchment was not monitored for the whole period but returned the highest DOC fluxes of the three catchments between January and June 2010 (15.7 g C m-2). These values are considered high for UK peatlands. It is possible to make a tentative estimate of an extra 12 g C m-2 being exported from the Crosswater of Luce in 2009 that may have been a result of wind farm and/or forestry activities in the catchment. At the sub-catchment scale, “hot spots” of high DOC concentrations (up to 113.4 mg L-1) were found during the final survey of headwater streams inside the development area of the wind farm site during construction in August 2010. Further surveys are recommended to assess whether DOC concentrations have decreased since completion of the wind farm. Daily water samples were collected upstream and downstream of turbine 33 during the excavation of the turbine base. DOC concentrations were higher downstream before work began on the turbine base and although the gap between upstream and downstream DOC concentrations increased over the monitoring period, statistical comparisons of these differences before and after the start of excavation work were not significant at the 95 % confidence level. Challenges arose from the practicability of conducting robust research on a construction site and novel approaches to monitoring DOC were developed. Activity scores were used to quantify the effect of peatland disturbance on DOC concentrations at the catchment scale. The results suggest that this approach may have merit but requires comprehensive site records from the developer. The non-linear nature of the individual wind farm development and forestry activities made it impractical to disentangle the impact of each, particularly for forest harvesting. iii Activity scores could, together with other information gathered from site records, be useful to developers as an indicator of the most likely periods for peat disturbance. Knowledge of the differing disturbance potential of the various activities could also provide useful information to feed into the carbon payback calculator. DOC quality was explored using ultraviolet (UV) absorbance, specific UV absorbance (SUVA) and E4/E6 ratios. The latter metric identified changes in the composition of DOC related to disturbance with water samples from areas draining land subject to disturbance having lower E4/E6 ratios indicating a greater degree of humification of the DOC. This research provides one of only three studies to investigate concentrations and fluxes of DOC in water courses draining land subject to disturbance relating to wind farm construction. It is the only study that incorporates a period of time prior to work beginning and takes in the whole of the development phase. In this respect it provides a valuable addition to our understanding of the way in which peatlands respond to land use change and may provide useful tools to assist developers in minimising the impact of their activities on these valuable carbon stores.
74

[en] FINANCIAL OPTIMIZATION OF A WIND FARM IN THE BRAZILIAN ENERGY MARKET / [pt] OTIMIZAÇÃO FINANCEIRA DE PARQUE EÓLICO NO MERCADO DE ENERGIA DO BRASIL

FERNANDO ORMONDE TEIXEIRA 23 March 2017 (has links)
[pt] Investigam-se modelos econométricos que sejam capazes de efetuar uma previsão mensal de vento em um parque eólico no Ceará. São testados modelos da família ARMA que consigam capturar a sazonalidade inerente ao movimento das massas de ar e que tragam benefícios aos empreendimentos eólicos localizados no Brasil e na região. Para tal, a previsão de vento é transformada em previsão de geração de energia. Em seguida, é elaborada uma metodologia para encontrar a melhor estratégia de ação a qual maximize o resultado da empresa tendo-se como meta o lucro e restrições de Value at Risk (VaR) e Conditional Value at Risk (CVaR). Os possíveis resultados de geração de energia são simulados concomitantemente com a simulação de preços de liquidação (PLD). / [en] We investigate econometric models that are capable of predicting the wind speed in a wind farm located in the state of Ceará, Brazil. ARMA models are tested to try to capture the seasonality inherent to the wind and that bring benefits to the firms operating wind farms in the region. Wind is converted in power generation to allow predictions to be more precise. Then, a methodology is created to find the best strategy, the one that maximizes the firm s profit. An optimization is made with VaR and CVaR as constraints. The simulated results of power generation are then put together with a simulation of liquidation s price (PLD).
75

Análise da estabilidade de sistema elétrico de potência com inserção de fontes renováveis

Walantus, Lucas Alejandro January 2014 (has links)
Nesta dissertação apresenta-se um estudo sobre o desempenho dinâmico do sistema elétrico de potência, frente à conexão de um parque eólico ligado através de conversores de frequência e de geradores síncronos de fontes hidrelétricas e termoelétricas. Dependendo da forma com que é gerenciado, este tipo de geração pode causar impactos significativos no sistema de energia elétrica. Este trabalho analisa o comportamento da estabilidade transitória nos sistemas de potência do ponto de vista da geração com inserção de fontes renováveis. Um sistema elétrico é proposto com dados reais do Rio Grande do Sul e modelado nos programas ANAREDE e ANATEM, considerando seus principais componentes, entre eles, linhas de transmissão, cargas, geradores e transformadores. São utilizadas estratégias de controle do programa ANATEM para a operação dos mesmos e estudar o comportamento do sistema elétrico de potência frente a diferentes eventos. Simulações são realizadas para investigar a influência de diversos fatores na resposta transitória do sistema. Os fatores analisados são: tempo de eliminação da falta, carregamento do sistema, níveis de geração das fontes tradicionais e das fontes eólicas. A análise dos resultados mostrara o impacto deste tipo de fontes instaladas no sistema em regime permanente e transitório. / This thesis introduces a study of an electric power system’s dynamic performance with traditional generation sources (hydro and thermoelectric) and wind farms. Depending on how it is managed, significant impact in the electric power system may occur. The power system transient stability is analyzed in this thesis considering the insertion of renewable energy resources. An equivalent power system is proposed with real data of Rio Grande do Sul and modeled using ANAREDE and ANATEM software, including as its main components, transmission lines, loads, generators and transformers. The control strategies present in the software ANATEM are used for the operation of these components, and then, to study the behavior of the electric power system against different events. Simulations are performed to investigate the influence of various factors on the transient response of the system. The factors analyzed are: time of fault clearing, system load, generation levels from traditional sources and wind sources. The analysis of the results shows the impacts of these specific resources in the system performance for steady state operation and transient state.
76

Análise da estabilidade de sistema elétrico de potência com inserção de fontes renováveis

Walantus, Lucas Alejandro January 2014 (has links)
Nesta dissertação apresenta-se um estudo sobre o desempenho dinâmico do sistema elétrico de potência, frente à conexão de um parque eólico ligado através de conversores de frequência e de geradores síncronos de fontes hidrelétricas e termoelétricas. Dependendo da forma com que é gerenciado, este tipo de geração pode causar impactos significativos no sistema de energia elétrica. Este trabalho analisa o comportamento da estabilidade transitória nos sistemas de potência do ponto de vista da geração com inserção de fontes renováveis. Um sistema elétrico é proposto com dados reais do Rio Grande do Sul e modelado nos programas ANAREDE e ANATEM, considerando seus principais componentes, entre eles, linhas de transmissão, cargas, geradores e transformadores. São utilizadas estratégias de controle do programa ANATEM para a operação dos mesmos e estudar o comportamento do sistema elétrico de potência frente a diferentes eventos. Simulações são realizadas para investigar a influência de diversos fatores na resposta transitória do sistema. Os fatores analisados são: tempo de eliminação da falta, carregamento do sistema, níveis de geração das fontes tradicionais e das fontes eólicas. A análise dos resultados mostrara o impacto deste tipo de fontes instaladas no sistema em regime permanente e transitório. / This thesis introduces a study of an electric power system’s dynamic performance with traditional generation sources (hydro and thermoelectric) and wind farms. Depending on how it is managed, significant impact in the electric power system may occur. The power system transient stability is analyzed in this thesis considering the insertion of renewable energy resources. An equivalent power system is proposed with real data of Rio Grande do Sul and modeled using ANAREDE and ANATEM software, including as its main components, transmission lines, loads, generators and transformers. The control strategies present in the software ANATEM are used for the operation of these components, and then, to study the behavior of the electric power system against different events. Simulations are performed to investigate the influence of various factors on the transient response of the system. The factors analyzed are: time of fault clearing, system load, generation levels from traditional sources and wind sources. The analysis of the results shows the impacts of these specific resources in the system performance for steady state operation and transient state.
77

Análise da estabilidade de sistema elétrico de potência com inserção de fontes renováveis

Walantus, Lucas Alejandro January 2014 (has links)
Nesta dissertação apresenta-se um estudo sobre o desempenho dinâmico do sistema elétrico de potência, frente à conexão de um parque eólico ligado através de conversores de frequência e de geradores síncronos de fontes hidrelétricas e termoelétricas. Dependendo da forma com que é gerenciado, este tipo de geração pode causar impactos significativos no sistema de energia elétrica. Este trabalho analisa o comportamento da estabilidade transitória nos sistemas de potência do ponto de vista da geração com inserção de fontes renováveis. Um sistema elétrico é proposto com dados reais do Rio Grande do Sul e modelado nos programas ANAREDE e ANATEM, considerando seus principais componentes, entre eles, linhas de transmissão, cargas, geradores e transformadores. São utilizadas estratégias de controle do programa ANATEM para a operação dos mesmos e estudar o comportamento do sistema elétrico de potência frente a diferentes eventos. Simulações são realizadas para investigar a influência de diversos fatores na resposta transitória do sistema. Os fatores analisados são: tempo de eliminação da falta, carregamento do sistema, níveis de geração das fontes tradicionais e das fontes eólicas. A análise dos resultados mostrara o impacto deste tipo de fontes instaladas no sistema em regime permanente e transitório. / This thesis introduces a study of an electric power system’s dynamic performance with traditional generation sources (hydro and thermoelectric) and wind farms. Depending on how it is managed, significant impact in the electric power system may occur. The power system transient stability is analyzed in this thesis considering the insertion of renewable energy resources. An equivalent power system is proposed with real data of Rio Grande do Sul and modeled using ANAREDE and ANATEM software, including as its main components, transmission lines, loads, generators and transformers. The control strategies present in the software ANATEM are used for the operation of these components, and then, to study the behavior of the electric power system against different events. Simulations are performed to investigate the influence of various factors on the transient response of the system. The factors analyzed are: time of fault clearing, system load, generation levels from traditional sources and wind sources. The analysis of the results shows the impacts of these specific resources in the system performance for steady state operation and transient state.
78

Contribution à la conception robuste de réseaux électriques de grande dimension au moyen des métaheuristiques d’optimisation / Contribution to the robust design of large electrical networks using metaheuristic's optimization

Ismail, Boussaad 06 May 2014 (has links)
Comme beaucoup de systèmes, un réseau électrique doit faire face à des pannes qui, compte tenu de sa grande connectivité, peuvent s'étendre à des régions entières : on parle alors de blackout (phénomène d'avalanche), c'est-à-dire ayant des conséquences à grande échelle. La taille des réseaux électriques et leur complexité rendent difficile la compréhension de ces phénomènes qui émergent localement. Un certain nombre de travaux existe et se fond sur un usage intensif des outils de physique statistique. L'adaptation de méthodes de percolation et les systèmes critiques auto-organisés sont autant d'outils de choix pour décrire les propriétés statistiques et topologiques d'un réseau. Les outils d'optimisation par métaheuristiques, plus particulièrement l'optimisation par essaim de particules (OEP, ou PSO en anglais) et les algorithmes génétiques (AGs), se sont révélés être la pierre angulaire de ce travail et ont permis de définir des structures opérationnelles. Les travaux développés dans ce domaine sont encore émergents et cette thèse y amène une contribution à plusieurs titres. Nous avons mis tout d'abord à profit des techniques d'optimisation afin de mieux “ rigidifier ” un réseau électrique en couplant la topologie de ce dernier au maintien des tensions aux noeuds du réseau par implémentation de FACTS (Flexible Alternative Current Transmission System). Pour le placement optimal de FACTS, l'objectif est de déterminer la répartition optimale de la puissance réactive, en relation avec la localisation et le dimensionnement optimal de FACTS, afin d'améliorer les performances d'un réseau électrique. Quatre principales questions sont alors abordées: 1) Où placer des FACTS dans le réseau ? Combien de FACTS ? Quelle puissance attribuer à ces FACTS ? Quel(s) type(s) de FACTS ? A quel prix ? Dans cette thèse, toutes ces questions seront modélisées et abordées d'un point de vue électrique et optimal en appliquant, dans un premier temps, l'optimisation par essaim de particules OEP basique puis, dans un deuxième temps, en proposant un nouvel algorithme OEP (alpha-SLPSO) et une recherche locale (alpha-LLS) s'inspirant ainsi du concept de l'OEP basique et des lois de probabilité stables dites «alpha-stables de Lévy». Par ailleurs, l'ampleur du projet défini par l'équipe @RiskTeam d'Alstom Grid oblige l'utilisation de plusieurs techniques (tirées de la physique, des statistiques, etc.) destinées à des fins particulières dont l'estimation des paramètres des lois alpha-stable de Lévy. Face à l'échec des techniques déjà existantes pour l'estimation des lois alpha −stable de paramètre alpha < 0.6 , nous proposons un nouvel estimateur semi-paramétrique de cette famille de probabilité utilisant les métaheuristiques pour résoudre le problème d'optimisation sous-jacent. Enfin, en annexe de cette thèse, un outil d'aide à la décision destiné à une équipe interne d'Alstom Grid qui consiste en l'optimisation de la topologie interne d'un parc éolien est détaillé dans le dernier chapitre / Like many systems, an electrical power grid must contend with faillures which, given its higth connectivity, could spread to entire regions: this is referred to blackout (avalanche phenomena), ie. with large-scale consequences. The size of power grids and their complexity make difficult to grasp these locally emergent phenomena. There is a number of existing works that were based on extensive use of statistical physics tools. The adaptation of percolation's methods and the Self-Organized-Criticality systems provide practical tools to describe the statistical and topological properties of a network. Optimization tools by metaheuristics particularly, particle swarm optimization (PSO) and genetic algorithms (GA) have proved to be the cornerstone of this work and helped to define operational structures. Works developed in this area are still emerging. This thesis brings a contribution in several ways. First of all, we have taken advantage in optimization technics to better "stiffen" a power grid by coupling its topology with maintaining voltages at the nodes of the network using FACTS (Flexible Alternative Current Transmission System). In the optimal location FACTS problem, the objective is to determine the optimal allocation of reactive power, in relation to the location and optimal sizing of FACTS, in order to improve the performance of the power grid. Four main issues are then discussed: 1) Where to place FACTS in the network? How many FACTS? What power attributed to these FACTS? What type(s) attributed to these FACTS? At what prices ? In this thesis, all these questions will be modeled and discussed from the point of view of optimal power by applying, firstly, the strandard particle swarm optimization and by proposing a novel particle swarm optimization (alpha-SLPOS) and a local search (alpha-LLS). These two algorithms are inspired by the basic concept of PSO and the stable distributions (alpha-stable laws). Moreover, the scope of the project defined by the team @RiskTeam Alstom Grid requires the use of several techniques (from physics, statistics, etc) for particular purposes including the alpha-stable parametere estimation problem. Facing the failure of the existing methods for estimating the parameters of alpha-stable laws for alpha<0.6, we propose a novel semi-parametric estimator for such of probability distribution familly using metaheuristic to solve the underlying problem of optimization. Finally, in the end of the thesis, a decision support tool is designed for an internal team of Alstom Grid to optimize the internal topology of a wind farm
79

Akumulace elektrické energie z OEZ / Power accumulation from renewable energy sources

Kratschmer, Bruno January 2013 (has links)
In this thesis I deal with problem of power acumulation from renewable energy sources. First part present the available technologies used for power accumulation. In the second part is designed the systém of acumulation in compressed air with a transformation electric output 1 MW, when is used made elektricity from wind-power plant. In the third part is an assessment in terms of both technical and economic comparison with the use of electicity from the network.
80

Une approche de gestion de la maintenance de parcs éoliens centrée sur les systèmes multiagents / A windfarm optimization and maintenance approach based on multiagent system

Kpakpo, Miguel 20 December 2018 (has links)
L’optimisation de la maintenance industrielle revêt différents aspects suivant les objectifs fixés par l’exploitant industriel. L’objectif le plus courant est la réduction des arrêts et des pannes. Le but est d’assurer une disponibilité élevée de l’équipement. Nous allons plus loin en nous posant la question de l’efficience des coûts de maintenance et de la rentabilité. La réponse donnée ici à cette question provient des résultats d’une fonction de coût associée à une plateforme de simulation basée sur les systèmes multiagents. Le choix du paradigme Agent est motivé par l’utilisation des SMA à d’autres fins de simulation et qu’ils garantissent une forme de souplesse quant à l’évolution du contexte métier. La thèse porte sur un modèle de systèmes multiagents destiné à améliorer la gestion des parcs éoliens à travers la définition d'un ensemble de critères financiers propres à l’exploitant éolien. / Optimization & maintenance in the Industrial sector covers different aspects according to the objectives set by the industrial operator. Their common goal is to reduce downtime and failures. For the windfarm operators the goal is to ensure the wind farms high availibility. We went one step further by asking the question of the efficiency of maintenance costs and the profitability. The answer to this question comes from the results of a cost function associated to a simulation model based on multiagents systems. The choice of the multiagent paradigm is motivated by the use of MAS for other simulation purposes and the fact that they guarantee a kind of flexibility regarding the evolution in a moving business context. This Phd thesis focuses on a multi-agent systems model designed to improve the management of wind farms through the definition of a set of financial criteria specific to the wind farm operators.

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