No / An isolated micro-grid network with limited generating capacity would most likely, end up having operational challenge either due to increasing number of customers, or introduction of new loads onto the network. This is in view of an observed scenario especially in developing countries whereby as load demand increases, installed PV capacity often do not receive commensurate expansion. So, in order to prevent network failure, each user can be allocated certain amount of limited power supply which should not be exceeded. These allotments are dynamic, and they vary at regular time intervals every day depending on their historic load profile data. This work is therefore based on managing power supply from a PV-source operating as an isolated micro-grid with storage capabilities. A power supply scheduling mechanism is introduced which allocates maximum power capacity for every user. Hence communities detached from the grid can enjoy electricity despite shortfalls in power supply capacity. The obtained results evaluated under three scenarios show that allocating energy limits to each user depends on the current capacity of the battery as well as the forecast load demand. This allotment is enforced using variable circuit breakers whose cut-off point is varied based on the prevailing energy demand and supply requirements.

This thesis studies a multiple-input single ended primary inductor converter (MI SEPIC) topology. The configuration allows the integration of different low-power distributed generation sources, such as individual photovoltaic modules, fuel cells, and small residential wind generators, into a common dc main bus. The current source interface allows the integration of all types of sources without the addition of filters; sources that require a nearly constant input current, such as fuel cells. In addition to discussing the circuit’s main models and operation, the thesis evaluates the stability under a decentralized PI control scheme through small signal analysis. The analysis is verified with simulations and experiments with prototypes. A derived circuit topology, the isolated MI SEPIC, is also explored here. In addition, a nonlinear control scheme, Lyapunov-based control, is implemented to stabilize an MI SEPIC. / text

A recente abertura de mercado, a carência de recursos públicos para investimentos em geração de energia, a dificuldade de realização de empreendimentos de grande porte por razão ambiental, bem como o programa de universalização do atendimento têm criado novas oportunidades no Setor Elétrico brasileiro, dentre as quais está a exploração de geração distribuída. Nesse âmbito, as micro redes que associam vários geradores de pequeno porte, operados por centro regional, vêm se revelando como uma interessante solução tanto para o investidor como para o atendimento de áreas de concessão específicas. Esta pesquisa apresenta um modelo de análise econômica da participação de geradores distribuídos, operando de forma pseudo-cooperativa, fundamentado na teoria dos jogos. O modelo foca o cliente, com futuro potencial de ser livre, capaz de gerar a sua própria energia através de geradores distribuídos. Uma micro-rede de geradores distribuídos pode ser constituída de vários agentes que, não obstante tenham toda ou parte de sua produção contratualmente comprometida, resolvem atuar de forma cooperada para auferir o ganho decorrente dos diferentes custos marginais de operação das máquinas, para cada nível de despacho de suas unidades. O modelo proposto prevê que a otimização da participação dos despachos das unidades cooperadas, em cada situação de carga, é obtida pela minimização global dos custos marginais totais, determinando a produção de cada gerador. O compartilhamento doganho advindo da cooperação é dado pela aplicação da Função de Shapley, que se fundamenta nas características técnicas e econômicas de operação de cada unidade. ) O modelo desenvolvido neste trabalho formulou o conceito pseudo-cooperação, que prevê a disponibilidade parcial da capacidade de geração de um ou mais agentes para produção dedicada à demanda cooperada da micro rede, de forma que a capacidade restante permanece para o agente oferecer a oportunidades do mercado. A otimização dos ganhos, tanto da rede cooperada como do agente que disponibiliza parte de sua capacidade ao mercado, é realizada através do compartilhamento do ganho da cooperação, da receita obtida da venda de energia ao mercado e do prêmio que o(s) agente(s) que transgride(m) sua(s) cota(s) mínima(s) de cooperação paga(m) aos participantes da cooperação. Com essa abordagem de cooperação parcial e otimização dos ganhos tornou-se possível maximizar os benefícios para os agentes e obter uma capacidade adicional, chamada neste trabalho de \"Sobra\", disponível para venda ao mercado. Desta forma, e como conclusão principal, pôde-se verificar que é possível a obtenção de ganhos adicionais sempre que um ou mais geradores trabalham de forma cooperada e que a pseudo-cooperação apresenta uma forma de aumentar esse ganho / The recent market expansion, the lack of public resources for investments in power generation, the difficulty of deployment of large projects due to environmental reasons, and also the program \"Universalização do Atendimento\" (program that aims to attend all country) has provided new opportunities on the Brazilian Electric Sector. One of these opportunities is the exploration of distributed generation. Under this idea, an interesting solution for the investor and also for the service provider in specific concession areas is the micro-grids. The micro-grids associate several small load generators it selves and these micro-grids are operated by regional centers. This research presents a model of economical analysis of the participation of distributed generators, operating in a pseudo-cooperative way, based in the game theory. The model adresses non free consumers that further may have the capability to be able to generate its own energy through distributed generators, as free consumers. A micro-grid of distributed generators can be composed by several agents that decide to act in a cooperative way aiming to earn from each level of dispatched power, through the different operational cost of the machines in the micro-grid. This is possible even having all or part the production already contractually committed. For each load situation, the proposed model foresees that the dispatch of power in each cooperated units is optimized by the global reduction of the costs thataffect the production of each generator. The share of the gain from the cooperation is given by the application of the Shapley function that is based in the technical and economical characteristics of operation of each unit. ) The developed model in this work has formulated a pseudo-cooperation concept, which foresees the partial availability of the generation capacity of one or more agents for dedicated production to the cooperated demand of the micro grid, so that the remaining capacity is available to be offered to opportunities of the market. The optimization of the gain over the cooperated grid, and also over the agent that make available its partial capacity to the market, is accomplished through the share of the cooperated gain, through the revenue obtained from the energy sold to the market, and also through the prize that the agents pay to other participants of the cooperation when they reach their minimal commitment. With the partial cooperation and gain optimization approach, it was possible to maximize the benefits for the agents and to obtain a surplus, called in this work of \"Sobra\", available to sell to the market. The main conclusion is that it is possible to obtain additional benefits whenever one or more generator work in a cooperative basis and that the pseudo-cooperation is a way to grown this benefits.

Universal access to electricity stands high on the global agenda and is regarded as essential for positive development in sectors such as health care, education, poverty reduction, food production and climate change. Decentralized, off-grid electrification is deemed an important complement to centralized grid extension. By utilizing a renewable energy source, solar technology for the generation of electricity, photovoltaics (PV) is being considered as a way forward to minimize the environmental problems related to energy use. This thesis aims to contribute to improving the technical and social feasibility of PV and PV-diesel hybrid micro-grids for the purpose of providing access to electricity to people in rural areas of countries with low level access to electricity. In line with these general aims, the focus has been to address three questions related to challenges in three phases of rural electrification. The work has a multi-disciplinary approach, addressing mainly technical and social aspects of long-term sustainability of micro-grids, in a local context, and the changes these are intended to generate. One specific micro-grid in Tanzania has been used as a major case study. The thesis is developed through three papers, all presenting methodologies or aspects for investigation in rural electrification projects and studies in general, and for PV-diesel hybrid micro-grids in particular. Paper I puts forward a methodology to facilitate non-social scientific researchers to take social aspects increasingly into consideration. Paper II is a guideline to support system users to increasingly apply an evaluation based system operation. Paper III specifically highlights the importance to consider blackouts when investigating how an existing off-grid PV-diesel hybrid system shall be utilized when a national grid becomes available.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-11-23T18:36:57Z No. of bitstreams: 1 Ricardo Machado Dias_.pdf: 9738672 bytes, checksum: 93b61d762b320f8c388034ac9d4ea82c (MD5) / Made available in DSpace on 2015-11-23T18:36:57Z (GMT). No. of bitstreams: 1 Ricardo Machado Dias_.pdf: 9738672 bytes, checksum: 93b61d762b320f8c388034ac9d4ea82c (MD5) Previous issue date: 2015-06-19 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / Este trabalho trata do desenvolvimento e do comissionamento de uma microrrede fotovoltaica de 1680 W pico conectada/isolada com estocagem para gerenciamento e controle de uma carga considerada crítica. Esta microrrede, empregando duas tecnologias de módulos, foi instalada no Laboratório de Energias Renováveis da Unisinos. A microrrede é composta de dois painéis de módulos, um de 1080 W de silício multicristalino, e um de 600 W de silício monocristalino. O primeiro é do sistema conectado à rede e o segundo é do sistema isolado, respectivamente. O sistema de gerenciamento e controle, chamado de supervisório, monitora e controla as duas redes através do sistema de aquisição de dados, que possui como tarefa o armazenamento dos dados em um cartão de memória além de mostrar em tempo real as variáveis envolvidas no processo através de um display de cristal líquido. São feitas análises dos valores de correntes e tensões, tanto alternada quanto contínua, para determinação das potências de entrada e de saída dos equipamentos envolvidos no processo, como também variáveis como temperatura ambiente e do painel FV e irradiância. A proposta deste estudo é demonstrar a disponibilidade do sistema para satisfazer uma carga que pode ser considerada como um processo crítico, a fim de entregar uma potência constante para a carga. Para isto, é necessário que a carga seja comutada entre os sistemas conectado à rede e isolado de acordo com as variáveis analisadas pelo sistema de aquisição de dados. As análises dos dados são divididas em duas partes: sistema FV conectado à rede e sistema isolado. Para cada sistema, foi analisado o comportamento da tensão, corrente e potência dos painéis fotovoltaicos, assim como o comportamento dos inversores e banco de estocagem de energia, considerando dias com céu claro e céu nublado. Para o dia de céu claro analisado, foi injetado na rede da concessionária 5,8 kWh de energia. A eficiência global, ηs deste sistema conectado ficou na ordem de 9 %. O sistema de aquisição de dados e controle da microrrede mostrou-se adequado com o propósito de alimentar a carga em permanência. Sempre que a rede da concessionária é desligada, a carga é automaticamente direcionada para o sistema isolado. Quando o banco de estocagem atinge 50 % de sua capacidade, a carga volta a ser alimentada pelo sistema conectado em paralelo com a rede da concessionária. / This work deals with the development and commissioning of a photovoltaic micro-grid 1680 W connected/alone with storage for management and control of a load considered critical. This micro-grid, employing two PV modules technologies, was installed on Renewable Energy Laboratory at Unisinos. The micro-grid panels is composed of two modules, a 1080 W multicrystalline silicon, and a 600 W of monocrystalline silicon. The first is a grid-connected system and the second is a stand-alone system, respectively. The management and control system, called supervisory, monitors and controls the two systems via data acquisition, which has the task of storing the data on a memory card in addition to showing real-time variables involved in the process through a liquid crystal display. Are made analysis of current values and voltages, AC and DC, to determine the input and output power of the equipment involved in the process, as well as variables such as ambient temperatures and PV module and irradiance. The purpose of this study is to prove availability of the system to meet a load that can be considered as a critical process, in order to maintain a constant power to the load. For this, it is necessary that the load is switched between systems connected to the grid and alone, according to the variables analyzed by the data acquisition system. The analyzes of the data are divided into two parts: PV grid-connected and alone system. For each system, the behavior of tension was analyzed, current and power of the PV panels, as well as the behavior of inverters and power storage bank, considering days with clear skies and overcast sky. For clear sky days analyzed, it was injected into the mains 5.8 kWh of energy. The overall efficiency of this system connected, ηs is 9 %. The data acquisition and control system micro-grid was adequate for the purpose of feeding a remaining charging. Whenever, the mains is switched off, the load is automatically directed to the alone system. When the storage capacity of the database reaches 50%, the load is once again powered by the connected system in parallel with the utility grid.

A recente abertura de mercado, a carência de recursos públicos para investimentos em geração de energia, a dificuldade de realização de empreendimentos de grande porte por razão ambiental, bem como o programa de universalização do atendimento têm criado novas oportunidades no Setor Elétrico brasileiro, dentre as quais está a exploração de geração distribuída. Nesse âmbito, as micro redes que associam vários geradores de pequeno porte, operados por centro regional, vêm se revelando como uma interessante solução tanto para o investidor como para o atendimento de áreas de concessão específicas. Esta pesquisa apresenta um modelo de análise econômica da participação de geradores distribuídos, operando de forma pseudo-cooperativa, fundamentado na teoria dos jogos. O modelo foca o cliente, com futuro potencial de ser livre, capaz de gerar a sua própria energia através de geradores distribuídos. Uma micro-rede de geradores distribuídos pode ser constituída de vários agentes que, não obstante tenham toda ou parte de sua produção contratualmente comprometida, resolvem atuar de forma cooperada para auferir o ganho decorrente dos diferentes custos marginais de operação das máquinas, para cada nível de despacho de suas unidades. O modelo proposto prevê que a otimização da participação dos despachos das unidades cooperadas, em cada situação de carga, é obtida pela minimização global dos custos marginais totais, determinando a produção de cada gerador. O compartilhamento doganho advindo da cooperação é dado pela aplicação da Função de Shapley, que se fundamenta nas características técnicas e econômicas de operação de cada unidade. ) O modelo desenvolvido neste trabalho formulou o conceito pseudo-cooperação, que prevê a disponibilidade parcial da capacidade de geração de um ou mais agentes para produção dedicada à demanda cooperada da micro rede, de forma que a capacidade restante permanece para o agente oferecer a oportunidades do mercado. A otimização dos ganhos, tanto da rede cooperada como do agente que disponibiliza parte de sua capacidade ao mercado, é realizada através do compartilhamento do ganho da cooperação, da receita obtida da venda de energia ao mercado e do prêmio que o(s) agente(s) que transgride(m) sua(s) cota(s) mínima(s) de cooperação paga(m) aos participantes da cooperação. Com essa abordagem de cooperação parcial e otimização dos ganhos tornou-se possível maximizar os benefícios para os agentes e obter uma capacidade adicional, chamada neste trabalho de \"Sobra\", disponível para venda ao mercado. Desta forma, e como conclusão principal, pôde-se verificar que é possível a obtenção de ganhos adicionais sempre que um ou mais geradores trabalham de forma cooperada e que a pseudo-cooperação apresenta uma forma de aumentar esse ganho / The recent market expansion, the lack of public resources for investments in power generation, the difficulty of deployment of large projects due to environmental reasons, and also the program \"Universalização do Atendimento\" (program that aims to attend all country) has provided new opportunities on the Brazilian Electric Sector. One of these opportunities is the exploration of distributed generation. Under this idea, an interesting solution for the investor and also for the service provider in specific concession areas is the micro-grids. The micro-grids associate several small load generators it selves and these micro-grids are operated by regional centers. This research presents a model of economical analysis of the participation of distributed generators, operating in a pseudo-cooperative way, based in the game theory. The model adresses non free consumers that further may have the capability to be able to generate its own energy through distributed generators, as free consumers. A micro-grid of distributed generators can be composed by several agents that decide to act in a cooperative way aiming to earn from each level of dispatched power, through the different operational cost of the machines in the micro-grid. This is possible even having all or part the production already contractually committed. For each load situation, the proposed model foresees that the dispatch of power in each cooperated units is optimized by the global reduction of the costs thataffect the production of each generator. The share of the gain from the cooperation is given by the application of the Shapley function that is based in the technical and economical characteristics of operation of each unit. ) The developed model in this work has formulated a pseudo-cooperation concept, which foresees the partial availability of the generation capacity of one or more agents for dedicated production to the cooperated demand of the micro grid, so that the remaining capacity is available to be offered to opportunities of the market. The optimization of the gain over the cooperated grid, and also over the agent that make available its partial capacity to the market, is accomplished through the share of the cooperated gain, through the revenue obtained from the energy sold to the market, and also through the prize that the agents pay to other participants of the cooperation when they reach their minimal commitment. With the partial cooperation and gain optimization approach, it was possible to maximize the benefits for the agents and to obtain a surplus, called in this work of \"Sobra\", available to sell to the market. The main conclusion is that it is possible to obtain additional benefits whenever one or more generator work in a cooperative basis and that the pseudo-cooperation is a way to grown this benefits.

The goal of the study was to evaluate the potential of the V2G system as a solution to peak load leveling and integrating more renewable energy in the microgrid of St. Martine Island. Simulink Simscape software was used to model a microgrid with a V2G system for the small community of the Island. The result of the study shows a V2G system with 100 electric cars could play an important role for peak shaving by supplying up to 0.8 MW of electric power back to the grid during peak hours, where each car contributes 10 kW of electric power. It also demonstrates that the V2G system effectively helps to promote solar power capacity from 1 MW to 2.5 MW, hence increase 23.59% share of solar energy in the total grid energy uses compared with the current microgrid of St. Martine Island. / The electricity that is generated from non-renewable sources causesenvironmental pollution and climate changes. Fossil fuel uses leads to thedepletion of fossil fuel resources as well as global warming. On the other hand, renewable energy sources can be used to produce electricity with very few or no CO2 emissions. So, now governments are focusing on renewable energy production. But solar, wind, and other types of renewable energy sources have intermittency. They are not continuously available due to natural factors that cannot be controlled. So, renewable energy needs to be utilized when it is available, or its intermittency can be overcome by energy storage. All Electric vehicle uses a battery pack of large capacity to power the electric motors. These batteries can be used to store the energy that is generated from renewable sources and use them when needed. Besides, the electric grid must always stay in balance. With the development of variable renewable energy production, the management of this balance has become complex. Vehicle to grid is a technology that enables energy to be pushed back to the grid from the battery of an electric car and helps to manage fluctuations on the electricity grid. It helps to balance the grid by charging the battery when renewableenergy is available and load demand is low, then sending energy back to the grid when load demand is high. However, St. Martine Island is a small Island in Bay of Bengal about 9km south of the mainland of Bangladesh. Nearly 6000 people are living there. Since the island is far away from the mainland, grid connection is almostimpossible in terms of cost and geographic location. St. Martine Island has a very high solar power potential, but very low average wind speed. Currently, the electricity demand is fulfilled by stand-alone diesel generators, PV panels, and wind turbines. The current microgrid gets a high load demand during peak hours which is between 6 pm to 11 pm. During this time grid become fully dependent on diesel generators which leads to fossil fuel uses andenvironmental pollution. Here, the project's key objective is to determine the prospects of V2Gtechnology on St. Martine Island to level the peak load during peak hours, given that St. Martine Island is a low windy island with a high average number of yearly peak sun hours. Another goal is to examine the degree to which the share of solar power can be increased by a V2G system in St. Martine Island. In the project, at first, we have modeled a microgrid using Simulink Simscape software. Simulink Simscape enables modeling of a system by putting direct physical connections between the block diagram. In the microgrid model, there are five main sections, which have been designed by assemblingfundamental components in the schematic. A V2G system has been modeled which consists of 100 electric cars as aprototype. Each car has a battery of 100 kWh capacity. Considering thecondition of St. Martine Island and the objective of the project, we have made some assumptions while modeling the V2G section. The results of the project showed that the V2G system significantly smoothed out the peak load during peak hours. It also demonstrated that charging electric cars during daytime by solar power and sending energy back to the grid during peak hours enables the V2G system to accommodate more renewable solar energy sources in the microgrid of St. Martine Island. Finally, the project evident that the V2G system can be integrated into the microgrid of St. Martine Island to level the peak load and to increase the share of solar energy in the total energy uses of the Island.

Universal access to electricity stands high on the global agenda and is regarded as essential for positive development in sectors such as health care, education, poverty reduction, food production and climate change. Decentralized, off-grid electrification is deemed an important complement to centralized grid extension. By utilizing a renewable energy source, solar technology for the generation of electricity, photovoltaics (PV) is being considered as a way forward to minimize the environmental problems related to energy use. This thesis aims to contribute to improving the technical and social feasibility of PV and PV-diesel hybrid micro-grids for the purpose of providing access to electricity to people in rural areas of countries with low level access to electricity. In line with these general aims, the focus has been to address three questions related to challenges in three phases of rural electrification. The work has a multi-disciplinary approach, addressing mainly technical and social aspects of long-term sustainability of micro-grids, in a local context, and the changes these are intended to generate. One specific micro-grid in Tanzania has been used as a major case study. The thesis is developed through three papers, all presenting methodologies or aspects for investigation in rural electrification projects and studies in general, and for PV-diesel hybrid micro-grids in particular. Paper I puts forward a methodology to facilitate non-social scientific researchers to take social aspects increasingly into consideration. Paper II is a guideline to support system users to increasingly apply an evaluation based system operation. Paper III specifically highlights the importance to consider blackouts when investigating how an existing off-grid PV-diesel hybrid system shall be utilized when a national grid becomes available.

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