The master’s thesis follows up the possibility of using renewable for making electric power. It detects conditions of further development in this discipline and external factors which are applied to business. It rates from economic view little hydroelectric, wind and photovoltaic power stations. In business plan it elaborates in detail prosecution of the little hydroelectric plants, which is at the end subjected to financial analysis and it’s decided if this business makes sense.

La présence de structures de vapeur dans la machine peut provoquer des dommages structurels et altérer les performances de la turbine. Ainsi, l’étude de la cavitation dans les machines hydrauliques est d’un très grand intérêt pour les industriels. Parmi les turbines hydrauliques, les turbines Kaplan sont réputées pour leur flexibilité. En effet, l’ouverture des directrices et la position des aubes de la roue peuvent être régulées en continu pendant l’utilisation de la machine, optimisant son rendement sur une large plage de fonctionnement. En contrepartie, Cela implique la présence de jeux entre les parties fixes et mobiles des turbines Kaplanà qui conduit à des structures de cavitation supplémentaires à ce niveau des machines. Dans ce contexte, l’objectif principal de cette thèse est de développer une méthodologie numérique capable de prédire et de caractériser la cavitation dans des turbines Kaplan et son impact sur les performances de la machine. Dans cette thèse, un modèle réduit de turbine Kaplan à 5 pales a été analysé. Les équations RANS/URANS ont été résolues,modélisant l’écoulement cavitant à l’aide d’une approche homogène et d’une loi d’état de type barotrope. Tout d’abord, la méthodologie a été définie pour des conditions de fonctionnement optimales, puis elle a été testée également sur un point de fonctionnement à forte charge. La méthode numérique de prédiction de la cavitation qui a été développée a pu être validée à l’aide de données expérimentales. Les prédictions numériques des performances et de l’évolution des structures de vapeur obtenues en appliquant la nouvelle stratégie de calcul de la cavitation sont en très bon accord quantitatif et qualitatif avec les données expérimentales. Une fois que la méthodologie numérique a été définie, des analyses approfondies de l’évolution des écoulements cavitants dans la machine ont été effectuées. L’approche développée apparaît très fiable, robuste et précise. / The presence of cavitation phenomena in hydraulic machines cause several structural damages and alter the machine performances. Hence, the investigation of the cavitation in hydraulic turbine is of great industrial interest. Amongthe hydraulic turbine, Kaplan turbine are known for their flexibility. The guide vane opening and the runner blade position can be continuously regulated during machine operation maximizing the efficiency for a large range of operating conditions. This implies the presence of shroud and hub gaps that leads to additional cavitation structures in the runner. In this context, the principal aim of this thesis is the development of a numerical methodology able to predict and characterize the cavitation in Kaplan turbine and its impact on the machine performance. The analysis refers to a scale model of a 5-blades Kaplan turbine. RANS/URANS equations have been solved modeling the cavitating flow by using a homogeneous approach and a barotropic state law. The methodology have been defined for optimal operating conditions and, after has been tested also on the full load operating point. Experimental data have been used to validate the developed numerical method of cavitation prediction. The numerical predictions of the performances and the vapor structures obtained by applying the new cavitation calculations strategy are in very good quantitative and qualitative agreement with the available experimental data. Once the numerical methodology has been defined in-deep analyses of the cavitating flow evolution in the machine have been performed. The developed approach appears to be very reliable, robust and precise.

The aim of this dissertation is to prepare a study of a small hydroelectric power plant as part of the Přelouč navigation level II. The preparation deals with one of the possible variants for the layout design of given constructions. The layout design of a weir with an adjacent lock chamber which secures navigability for the stretch of the Elbe River located between the river kilometers 949,23 and 951,20 near the city of Přelouč in the Pardubice District is also included in the study. The introduction chapter contains the assessment of the environment, which is followed by the specification of the exact placement of the constructions. In the following chapter, a particular type of the hydroelectric power plant machinery is designed based on the available hydrological information and gradient conditions. The final chapter contains the design of the constructional technological layout of an machine room in the form of a technical report and drawing documentation.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 135-137. / by Katherine Oven Thompson. / M.S.

Aus Thermalwässern mit Temperaturen nur wenig über der Kühltemperatur ist die Stromgewinnung bisher nicht wirtschaftlich. Ein neuartiger Konvektionsgenerator soll das ändern. Er lässt sich auch für insustrielle Rest- oder Abwärme einsetzen.

The aim of this study is to analyse the voltage regulation of a power grid when wind power parks are connected to an existing power grid. Secondary the project have studied the placement of these wind power parks and costs related to connecting them to the grid. The goal was to achieve this grid with a smaller than 5% voltage margin and preferably a low phase deviation. The power grid is located in the area around Lule älven. Several issues with constructing and connecting windpower parks to an electrical grid have been studied by numerical analysis of a fictive grid but with real world variables. A balanced and stable grid is achieved with wind and hydro power and is able to successfully operate without non-renewable energy sources.The data was simulated in Matlab to analyse the power grid and the modification of it when connecting the wind power parks. The method used is power flow analysis through Matlab. All required unknown voltages and phase angles are determined and whether they are within given specifications. This entails that a stable electrical grid can be constructed

[pt] Os reservatórios de Vigário e de Santana são parte da bacia do Paraíba do Sul que fornecem água para três hidroelétricas integradas do sistema de energia da Light, com uma capacidade de geração de energia de 612 MW. Considerando o aumento da demanda e do fornecimento de energia, a operação das hidroelétricas gera mudanças no perfil de ocupação do solo, com consequente impacto nas taxas de erosão. Como consequência, os parâmetros originais relacionados ao assoreamento do reservatório não são mais aplicáveis, resultando numa vida útil menor do que a prevista nos projetos originais. Dentro das alternativas que permitem recuperar dados sobre a variação da velocidade de sedimentação em escala anual, diversos estudos destacam o uso do 210Pb. Este trabalho discute o estudo de testemunhos retirados em diferentes pontos dos reservatórios de Santana e de Vigário. Os perfis de umidade qualificaram 4 testemunhos para serem analisados através da técnica do 210Pb empregando o modelo CRS. Os metais Cr e Zn apresentaram valores de concentração acima do seu valor de TEL, e podem estar causando algum efeito colateral na fauna e flora da região. A datação por 210Pb evidenciaram um aumento significativo das velocidades de sedimentação. O aumento observado nos testemunhos de Vigário foi superior ao verificado no testemunho de Santana. Foi observado um lento incremento na taxa de sedimentação do reservatório de Vigário até o final da década de 1990, já Santana apresentou aumentos e reduções ao longo dos anos, sugerindo que este seja mais susceptível a variações anuais. / [en] The Vigario and Santana reservoirs are part of the Paraiba do Sul basin which supply water to three hydroelectric plants integrated in Light s energy system, with a power generation capacity of 612 MW. Considering the increase in energy demand and supply, the operation of hydroelectric plants brings changes in the soil occupation profile, and consequently, impacts on the erosion rates. Under the circumstances, the original parameters related to the silting of the reservoir are no longer applicable, resulting in a shorter useful life than expected in the original projects. Among the alternatives for recovering historical data on the variation of the sedimentation velocity on an annual scale, several studies highlight the use 210Pb. This work discusses the study of samples taken from different regions of the Santana and Vigario reservoirs. The moisture profiles qualified 4 cores to be analyzed using the 210Pb technique using the CRS model. The metals Cr and Zn showed concentration values above their TEL value, and may be causing some side effect on the fauna and flora of the region. The 210Pb dating showed a significant increase in sedimentation velocities. The increase observed in the Vigario cores was higher than that observed in the Santana core. A slow increase in the sedimentation rate of the Vigario reservoir was observed until the end of the 1990s, while the Santana reservoir showed increases and decreases over the years, suggesting that Santana is more susceptible to annual variations.

Submitted in fulfillment of the requirements of the Degree of Master of Technology: Chemistry, Durban University of Technology, 2014. / This project arose out the need for a simple method to analyse NOM on a routine basis. Water samples were obtained from the Vaal dam, which is one of the dams used by a hydroelectric power station. Analysis was preceded by separation of NOM into the humic and non-humic portions. The humic portion was separated into two fractions by employing a non-ionic resin (DAX-8) to separate humic acid from fulvic acid. High performance size exclusion chromatography (HPSEC), equipped with an Ultraviolet( UV) detector and an Evaporative Light Scattering (ELS) detector connected in series, was used to obtain molecular weight distribution information and the concentration levels of the two acids. Mixed standards of polyethylene oxide/glycol were employed to calibrate the selected column. Suwanee River humic acid standard was used as a certified reference material. The molecular weight distributions (MWDs) of the isolated fractions of humic and fulvic acids were determined with ELSD detection as weight-average (Mw), number-average (Mn) and polydispersity (ρ) of individual NOM fractions. The Mw/Mn ratio was found to be less than 1.5 in all the fractions, indicating that they have a low and narrow size fraction. An increase in Mn and Mw values, with increasing wavelength for all three humic substances (HS) examined was observed. The HS, isolated from the dam water, was found to be about the same molecular weight as the International Humic Acid Standard (IIHSS). For the fulvic acid standard, the molecular weight was estimated to be around 7500 Da. Characterization of NOM was done to assist in the identification of the species present in the water. FTIR-ATR was used to as a characterization tool to identify the functional groups in the structure of the humic and fulvic acid respectively present in the Vaal Dam. Analysis of the infrared (IR) spectra indicated that the humic acids of the Vaal dam have phenolic hydroxyl groups, hydroxyl groups, conjugated double bond of aromatic family (C=C), and free carboxyl groups. The isolation method has proved to be applicable and reliable for dam water samples and showed to successfully separate the humic substances from water and further separate the humic substances into its hydrophobic acids, namely, humic and fulvic acids. It can be concluded that the Eskom Vaal dam composes of humic substance which shows that the technique alone gives a very good indication of the characteristics of water. The HPSEC method used, equipped with UV and ELSD was able to identify the molecular weight range of NOM present in source water as it confirmed that the Eskom Vaal dam contains humic substances as humic acid and fulvic acid and these pose a health concern as they can form disinfectant byproducts in the course of water treatment with chemicals. FTIR characterization was successful as important functional groups were clearly assigned. Lastly, the use of the TOC and DOC values to calculate SUVA was also a good tool to indicate the organic content in water. It is recommended to use larger amounts of water must be processed to obtain useful quantities of the humic and fulvic acid fractions.

Tipos litológicos basálticos provenientes do maciço de fundação da UHE Canoas I foram submetidas a ensaios de caracterização tecnológica com o propósito do seu emprego como material de construção. Foram determinados os valores dos índices físicos (massa específica, porosidade, absorção d\'água), da velocidade de propagação de ondas ultra-sônicas e efetuados ensaios de compressão uniaxial e diametral, entre outros, além de análises petrográficas. Executaram-se, também, ensaios de alterabilidade acelerada (água-estufa, imersão em etileno-glicol) e de alterabilidade natural, tanto em fragmentos de rocha como em testemunhos de sondagens rotativas. São descritos em maior detalhe, os procedimentos utilizados para a realização do ensaio de alterabilidade natural em testemunhos de sondagens rotativas. Analisa-se a influência de uma feição geológica (caixa de falha com cerca de 10 m de espessura e 20º de ângulo de mergulho), presente na fundação, nas propriedades tecnológicas dos tipos litológicos por ela interceptados. São indicados os tipos litológicos selecionados para a utilização como material de construção. / Basaltic litotypes from the rock mass foundation of Canoas I Hydroelectric Power Plant were submitted to technological characterization tests, in order to verify their suitability as construction material. Physical and mechanical properties (density, porosity, water absorption, ultrasonic velocity, compressive and splitting tensile strength, among others) were determined, besides petrographic analyses. Weatherability tests were also performed, not only through wetting-drying cycles and by immersion in ethylene glycol but by outdoor exposure as well, using crushed and core drilled specimens. Detailed procedures for the weatherability test using core specimens from rotary drilling are given. It is analysed the influence of a geological feature (fault zone, about 10 meters thick and 20 degrees dip), that occurs in the rock mass foundation, on the technological properties of these rocks. Basaltic litotypes selected as construction material are then pointed out.

A geração de energia elétrica é importante para todos os ramos de atividades econômicas e tem demanda crescente. Isso implica constantes melhorias dos sistemas secundários, entre eles os sistemas de automação, que evoluíram muito nos últimos anos. Em várias usinas hidrelétricas esses sistemas estão obsoletos e apresentam outros problemas, portanto, carecem de atualizações tecnológicas. O objetivo desta tese é responder às principais questões relacionadas às modernizações dos sistemas de automação de unidades geradoras hidráulicas de grande porte: por que, quando e como modernizá-los? Para isso, foram estudados a evolução desses sistemas, o estado da arte, as modernizações já realizadas e planejadas. Os dados foram obtidos da bibliografia e diretamente de especialistas, através de pesquisa de campo envolvendo as principais concessionárias brasileiras. Baseando-se nos estudos, foram elaborados critérios para tomar a decisão por modernizar, foram escolhidas a forma de modernização e de realização mais adequadas para grandes usinas e foi criado um modelo de sistema de automação usando o estado da arte. Esse modelo é totalmente digital, utiliza uma única rede de comunicação em todos os níveis (incluindo o controle central), é à prova de futuro e fundamenta-se na norma IEC 61850. Todos os componentes e características do sistema foram examinados. Por fim, foi proposto um método para especificação e projeto do novo sistema incluindo todas as etapas. Concluiu-se que, um conjunto de indicadores quantitativos pode decidir a necessidade de modernização dos sistemas de automação de grandes unidades geradoras e, tomada a decisão por modernizar, a melhor solução é a substituição total de uma só vez (uma parada) usando o modelo criado. Os métodos e o sistema propostos podem ser usados como referências no setor elétrico para facilitar as atualizações tecnológicas e garantir resultados efetivos uniformes, com longo tempo de vida e independência dos fornecedores. / The generation of electricity is important to all branches of economic activities and faces a growing demand. This implies constant improvements of the secondary systems, including the automation systems, which have evolved a great deal in recent years. At several hydroelectric power plants these systems are obsolete and present other problems, therefore, technological upgrades are required. The objective of this thesis is to answer the key questions related to the modernizations of automation systems of large hydraulic generating units: why, when and how to modernize them? To this effect, studies were undertaken about the evolution of these systems, the state of the art, the modernizations already introduced and those planned. The data were obtained from the bibliography and directly from experts, through a field survey involving the major Brazilian utilities. Based on these studies, criteria to support the modernization decision were developed, the most suitable manner of modernization and of its implementation in large power plants were chosen and an automation system model using state of the art was created. This model is fully digital, uses only one communication network at all levels (including the central control), is future proof and is based on the IEC 61850 standard. All components and features of the system were examined. Finally, a method including all stages for specification and design of the new system was proposed. It was concluded that, a set of quantitative indicators can decide the need for modernization of the automation systems of large generating units and, once the decision to modernize is taken, the best solution is the total replacement during a single unit shut-down using the model created. The methods and system proposed can be used as references in the electricity sector to facilitate the technological upgrades and to ensure effective uniform results, with the prospect of a long service life and independence from the suppliers.