The rise of environmental awareness as well as the unstable global fossil fuel market has brought about government initiatives to increase electricity generation from renewable energy sources. These resources tend to be geographically and electrically remote from load centres. Consequently many Distributed Generators (DGs) are expected to be connected to the existing Distribution Networks (DNs), which have high impedance and low X/R ratios. Intermittence and unpredictability of the various types of renewable energy sources can be of time scales of days (hydro) down to seconds (wind, wave). As the time scale becomes smaller, the output of the DG becomes more difficult to accommodate in the DN. With the DGs operating in constant power factor mode, intermittence of the output of the generator combined with the high impedance and low X/R ratios of the DN will cause voltage variations above the statutory limits for quality of supply. This is traditionally mitigated by accepting increased operation of automated network control or network reinforcement. However, due to the distributed nature of RES, automating or reinforcing the DN can be expensive and difficult solutions to implement. The Thesis proposed was that new methods of controlling DG voltage could enable the connection of increased capacities of plant to existing DNs without the need for network management or reinforcement. The work reported here discusses the implications of the increasing capacity of DG in rural distribution networks on steady-state voltage profiles. Two methods of voltage compensation are proposed. The first is a deterministic system that uses a set of rules to intelligently switch between voltage and power factor control modes. This new control algorithm is shown to be able to respond well to slow voltage variations due to load or generation changes. The second method is a fuzzy inference system that adjusts the setpoint of the power factor controller in response to the local voltage. This system can be set to respond to any steady-state voltage variations that will be experienced. Further, control of real power is developed as a supplementary means for voltage regulation in weak rural networks. The algorithms developed in the study are shown to operate with any synchronous or asynchronous generation wherein real and reactive power can be separately controlled. Extensive simulations of typical and real rural systems using synchronous generators (small hydro) and doubly-fed induction generators (wind turbines) have verified that the proposed approaches improve the voltage profile of the distribution network. This demonstrated that the original Thesis was true and that the techniques proposed allow wider operation of greater capacities of DG within the statutory voltage limits.

Submitted by ANDREY MININ MARTIN null (andrey_mm@hotmail.com) on 2016-07-05T15:09:13Z No. of bitstreams: 1 Tese Andrey Martin_UNESP 2016.pdf: 5746818 bytes, checksum: 15e4affba34a9ac0ee840e4d35b09583 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-07-07T19:50:56Z (GMT) No. of bitstreams: 1 martin_am_dr_assis.pdf: 5746818 bytes, checksum: 15e4affba34a9ac0ee840e4d35b09583 (MD5) / Made available in DSpace on 2016-07-07T19:50:56Z (GMT). No. of bitstreams: 1 martin_am_dr_assis.pdf: 5746818 bytes, checksum: 15e4affba34a9ac0ee840e4d35b09583 (MD5) Previous issue date: 2016-05-24 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Objetiva-se neste trabalho analisar o Complexo Hidrelétrico Urubupungá, localizado na região fronteiriça entre os estados de São Paulo e Mato Grosso do Sul, constituído por duas hidrelétricas, a Usina Hidrelétrica Engenheiro Souza Dias (Jupiá) e a Usina Hidrelétrica Ilha Solteira. Planejado e executado entre as décadas de 1950 e meados da década de 1970, este empreendimento consolida-se por meio da criação da Comissão Interestadual da Bacia do Paraná-Uruguai, a CIBPU, projeto de planejamento regional articulado por sete estados nacionais, tendo como influência as experiências norte-americanas do Tennessee Valley Authority, TVA. Com o início das obras, a condução do empreendimento centraliza cada vez mais novos organismos, como as Centrais Elétricas de Urubupungá, CELUSA S/A e a partir de 1966 as Centrais Elétricas de São Paulo, CESP, atualmente denominada Companhia Energética de São Paulo. Tais transformações projetam novos interesses de determinados grupos e espaços com as potencialidades advindas da produção energética, ampliando diretamente a forma de se pensar como a constituição deste complexo atrela-se a determinados projetos políticos, econômicos e sociais para uma vasta região do país. Para tal análise, permeado por um debate teórico-metodológico entre progresso, desenvolvimento, história e memória, ligados a um corpo documental amplo, de documentos de comissões e empresas, periódicos de circulação nacional e aparatos audiovisuais, apresentamos como uma série de narrativas se engendraram na execução e no estabelecimento do empreendimento, articulando seu ideário de progresso e uma nova imagem para região, antes, durante e posteriormente a sua realização. Desta forma, interesses privados, disputas pela legitimidade, pelo poder e, assim, memórias foram gestadas ao longo deste período e marcaram a construção do complexo hidrelétrico até seu término na década de 1970, estabelecendo ligações com marcos de memória do passado e deixando desdobramentos para o futuro. / This work aims to analyze the Urubupungá Hydroelectric Complex, located in the border region between the States of São Paulo e Mato Grosso do Sul, it is consisted by two hydroelectric plants, the Engenheiro Souza Dias Hydroelectric Plant (Jupiá), and the Ilha Solteira Hydroelectric Plant. Planned and executed between the decade of 1950 and mid of 1970, this enterprise consolidated itself through the creation of an Interstate Committee of the Paraná-Uruguai basin, that was called CIBPU, and was a regional planning project articulated by seven national States, under the influence the North-American experiences of the Tennessee Valley Authority, TVA.With the beginning of the works, the enterprise focuses more and more on the new organisms, such as Urubupungá Electrics Centrals, CELUSA S/A, and from 1966, The São Paulo Electrics Centrals, CESP, currently named as Energetic Company of São Paulo. These transformations design new interests of certain groups and spaces to the arising potential from the energy production, directly widening the way of thinking about how the complex creation is connected to certain political, economic, and social projects to a wide area of the country. For this analysis, permeated by a theoreticalmethodological debate about progress, development, history and memory linked to an extensive documental source of commissions and companies documents, national periodicals, audio-visual apparatus, it was presented how a series of narratives were engendered in the enterprise implementation and establishment, articulating its ideals of progress and a new image for the region, before, during, and after its completion. In this way, private interests, disputes for the legitimacy and power, and so, memories were made throughout this period and marked the Hydroelectric Complex construction until its completion in early 1970, establishing connections with landmarks of memory from the past and developments for the future. / FAPESP: 2012/16777-1

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.