Made available in DSpace on 2014-06-11T19:22:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-25Bitstream added on 2014-06-13T18:49:35Z : No. of bitstreams: 1 souza_ssf_me_ilha.pdf: 808468 bytes, checksum: b5fdf2d46cfc01fa8badedc74f75df55 (MD5) / Neste trabalho apresenta-se uma metodologia para resolver o problema de reconfiguração de sistemas de distribuição de energia elétrica, que é modelado como um problema de Programação Não Linear Inteiro Misto (PNLIM). Para resolver este problema utilizou-se a metaheurística GRASP especializada. O objetivo do problema de reconfiguração de sistemas de distribuição de energia elétrica é encontrar a melhor topologia radial para um sistema de distribuição de energia elétrica de forma que as perdas ativas do sistema sejam as menores possíveis. Na metodologia proposta, todas as chaves de interconexão do sistema de distribuição estão abertas no inicio do processo e a cada passo um circuito é conectado no sistema e uma solução factível é construída. O algoritmo GRASP foi escrito na linguagem de modelagem matemática AMPL onde a cada iteração é resolvido um problema de programação não linear utilizando o solver comercial KNITRO. Para evidenciar a eficácia da metodologia proposta foram realizados testes com sistemas de 14, 33, 70, 84, 119, 136 e 417 barras, estes resultados são comparados com os resultados encontrados na literatura especializada / This work presents a methodology to solve the electric power distribution systems reconfiguration problem, which is modeled as a Mixed Integer Nonlinear Programming problem (MINLP). Specialized metaheuristic GRASP was used to solve the problem. The aim of the reconfiguration problem is to find the best topology for a radial electric power distribution system so that the active power losses are as small as possible. In the proposed methodology, at the beginning of the solution process all switches that interconnect the distribution system are open and in each next step a circuit is connected to the distribution system and therefore a feasible solution is constructed. The GRASP algorithm was written in AMPL mathematical modeling language where in each iteration was solved a nonlinear programming problem using the commercial solver KNITRO. To demonstrate the effectiveness of the proposed methodology, tests were performed with distribution systems of 14, 33, 70, 84, 119, 136, and 417 buses, these results are compared with results found in literature

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Com o aumento na demanda de energia elÃtrica e a exigÃncia de maior confiabilidade, seguranÃa e eficiÃncia na operaÃÃo de sistemas elÃtricos de potÃncia por parte dos ÃrgÃos reguladores, aumentou a necessidade por profissionais cada vez mais qualificados em planejamento e operaÃÃo dos sistemas de potÃncia. No entanto, com a necessidade de atualizaÃÃo tÃcnica continuada e em decorrÃncia da polÃtica de racionalizaÃÃo de custos e de disponibilizaÃÃo de pessoal, as tÃcnicas de ensino a distÃncia tÃm evoluÃdo e alcanÃado abrangÃncia nas mais diferentes Ãreas do conhecimento. Este trabalho apresenta um Simulador para Treinamento Presencial e a DistÃncia em OperaÃÃo e ProteÃÃo de Sistemas ElÃtricos (STOP). O simulador STOP à desenvolvido em Java, podendo ser utilizado em ambientes: Unix, Linux, Windows, MacOS. O STOP pode ser aplicado em treinamento presencial e a distÃncia e està voltado à capacitaÃÃo de estudantes de engenharia, tÃcnicos e profissionais da Ãrea de sistemas elÃtricos de potÃncia. O STOP està integrado a um Ambiente Virtual de Aprendizagem (AVA), o Moodle. A integraÃÃo enriquece o ensino-aprendizado tornando-o mais efetivo com o uso de uma ferramenta capaz de simular situaÃÃes reais. Os simuladores em ambientes virtuais sÃo alternativas para a reduÃÃo de custos em empresas e instituiÃÃes de ensino. O simulador STOP à um software composto de diagramas unifilares, com a representaÃÃo dos principais componentes do sistema de proteÃÃo, tornando possÃvel ao usuÃrio simular faltas e reconfigurar o sistema elÃtrico, por meio de ajustes de relÃs para coordenaÃÃo da proteÃÃo e redefiniÃÃo de parÃmetros. / As the demand for electrical energy increases and requirements from regulatory agencies for improved reliability, security and efficiency on the operation of electric power systems, the need for professionals ever more qualified on planning and operation power systems also increases. However, with the need for continued technical update and as a result of rationalization policies of costs and provision of personnel for training, the distance learning techniques have evolved and reached different areas of knowledge. This work presents a Simulator for Presence and Distance Learning about Operation and Protection of Electric Systems (STOP). The STOP Simulator is developed in Java, which enables it to be used in the following systems: Unix, Linux, Windows, MacOS. The STOP can be applied in class as well as distance training and is directed to the training of engineering students, technicians and professionals specialized on electric power systems. The STOP is integrated to a Learning Virtual Environment (AVA), the Moodle. The integration enhances the teaching-learning process making it more effective by using a tool able to simulate real life situations. Simulators in virtual environments are an alternative to reducing costs in companies and educational institutions. The STOP is a software tool featuring one-line diagrams with the main components of the protection system, short-circuits simulation and reconfiguration of the system by setting relays for coordination of the system protection and redefinition of parameters.

Orientador: Rubén Augusto Romero Lázaro / Coorientador: Marcos Julio Rider Flores / Banca: Jose Roberto Sanches Mantovani / Banca: Secundino Soares Filho / Resumo: Neste trabalho foi desenvolvido um modelo baseado em programação linear inteira mista para determinar o custo mínimo da operação de um sistema hidrotérmico de longo prazo em um mercado elétrico competitivo. O modelo é capaz de encontrar os valores ótimos de operação para um período futuro nas usinas térmicas e hidroelétricas, considerando os limites normais e de emergência e as perdas de potência ativa nas linhas de transmissão, para diferentes níveis de carregamento, com múltiplos reservatórios de acumulação e de regulação. Adicionalmente, a previsão da hidrologia foi modelada mediante modelo SARIMA para o período de análise, considerando o histórico dos dados hidrológicos. O modelo foi implementado na linguagem de modelagem matemática GMPL. O problema de programação linear inteira mista foi resolvido usando o solver GLPSOL. As predições das hidrologias foram feitas na linguagem estatística R. Foi desenvolvida uma interface gráfica para gerenciar o modelo em GMPL, a previsão hidrológica em R e o solver GLPSOL na linguagem Qt. Desta forma é possível adicionar novos modelos, alterar dados do modelo e visualizar os resultados. Todas as linguagens e softwares usados são livres de distribuição e modificação. Para o modelo desenvolvido foram analisados os seguintes casos: sistema de 6 barras; sistema uninodal brasileiro e sistema interligado peruano. Os resultados obtidos foram comparados com os resultados encontrados na literatura com o objetivo de validar a proposta deste trabalho / Abstract: In this work developed a model based on mixed integer linear programming to determine the minimum cost of operation of a hydrothermal system in a long-term competitive electricity market. The model is able to find the optimal values of operation for a future period in thermal and hydroelectric power plants, considering the normal and emergency limits and the active power losses in transmission lines, for different loading levels, with multiple storage reservoirs and dams. In addition, predicting the hydrology was modeled by the SARIMA model for the period of analysis, considering the hydrological historical data. The model was implemented in the language of mathematical modeling GMPL. The mixed linear integer programming problem was solved using solver GLPSOL. The predictions in the hydrology using the statistical language R. It was developed a graphical interface to manage the GMPL model, the hydrologic forecasting, and solver GLPSOL in Qt graphical language. By this way, is possible to add new models, change the data of the model and view the results. All languages and software used are free to distribute and modify. For the model developed the following cases were analyzed: 6 bar system; Brazilian uninodal system and Peruvian interconnected system. The results were compared with results in the literature in order to validate the proposal of this work / Mestre

Orientador: Rubén Augusto Romero Lázaro / Coorientador: Marina Lavorato de Oliveira / Banca: José Roberto Sanches Mantovani / Banca: Arturo Suman Bretas / Resumo: Neste trabalho apresenta-se uma metodologia para resolver o problema de reconfiguração de sistemas de distribuição de energia elétrica, que é modelado como um problema de Programação Não Linear Inteiro Misto (PNLIM). Para resolver este problema utilizou-se a metaheurística GRASP especializada. O objetivo do problema de reconfiguração de sistemas de distribuição de energia elétrica é encontrar a melhor topologia radial para um sistema de distribuição de energia elétrica de forma que as perdas ativas do sistema sejam as menores possíveis. Na metodologia proposta, todas as chaves de interconexão do sistema de distribuição estão abertas no inicio do processo e a cada passo um circuito é conectado no sistema e uma solução factível é construída. O algoritmo GRASP foi escrito na linguagem de modelagem matemática AMPL onde a cada iteração é resolvido um problema de programação não linear utilizando o solver comercial KNITRO. Para evidenciar a eficácia da metodologia proposta foram realizados testes com sistemas de 14, 33, 70, 84, 119, 136 e 417 barras, estes resultados são comparados com os resultados encontrados na literatura especializada / Abstract: This work presents a methodology to solve the electric power distribution systems reconfiguration problem, which is modeled as a Mixed Integer Nonlinear Programming problem (MINLP). Specialized metaheuristic GRASP was used to solve the problem. The aim of the reconfiguration problem is to find the best topology for a radial electric power distribution system so that the active power losses are as small as possible. In the proposed methodology, at the beginning of the solution process all switches that interconnect the distribution system are open and in each next step a circuit is connected to the distribution system and therefore a feasible solution is constructed. The GRASP algorithm was written in AMPL mathematical modeling language where in each iteration was solved a nonlinear programming problem using the commercial solver KNITRO. To demonstrate the effectiveness of the proposed methodology, tests were performed with distribution systems of 14, 33, 70, 84, 119, 136, and 417 buses, these results are compared with results found in literature / Mestre

No description available.

<p>Power system maintenance optimisation involves obtaining the minimum total costs, including preventive and corrective maintenance costs and the cost of failures for both supplier and customer. To calculate the cost of failure, information is needed about the equipment reliability characteristics. It is also necessary to know how maintenance affects component reliability. The aim of the work leading up to this thesis has been to develop reliability models that include the effect of maintenance.</p><p>Three case studies have been carried out for different types of power system components using three distinct methods. In the first study the reliability of the first generation XLPE cables was modelled with respect to failures caused by water treeing using load-strength modelling. The model was based on assumptions of the ageing process and the distribution system characteristics. This study showed that it is possible to and overvoltage and insulation characteristics that can be fitted to agree with failure statistics for water tree ageing in XLPE cables. The second case study included a study of all circuit breaker failures in the Swedish transmission grid during the period from 1 January 1999 to 30 June 2003. In a subsequent investigation a method to combine information from the design process with maintenance records and failure statistics was employed using Bayesian methods. The resulting reliability model is continuously updated as more failure and maintenance data</p><p>becomes available. This case study showed that it is possible to develop reliability models for components that have not yet failed by utilising information from the design process and right-censored observations from inspections. Finally, in the third case study a quantitative method for establishing the condition of disconnector contacts by the use of thermography was developed. Two sets of measurements on disconnector contacts in the Swedish transmission</p><p>grid were carried out to establish the accuracy of the method. By utilising the results from the measurements estimates of the statistical distributions of the error sources were produced.</p><p>The results from the case studies show that the lack of detailed, high-quality data remains a critical problem when modelling reliability of power system equipment, even when using methods that require a minimum of data.</p>

Orientador: Madson Cortes de Almeida / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-24T01:13:38Z (GMT). No. of bitstreams: 1 Dardengo_VictorPellanda_M.pdf: 2575363 bytes, checksum: 30d6d4f10eba96b3baa38c14dae17316 (MD5) Previous issue date: 2013 / Resumo: No planejamento de sistemas de medição para estimação de estado de sistemas de energia elétrica são definidos os tipos, a localização e a quantidade de medidores. Um plano de medição adequado deve garantir a observabilidade da rede, viabilizando a estimação do estado de toda a rede, e permitir a filtragem de erros grosseiros. Para que os erros grosseiros possam ser filtrados é necessário que no plano de medição não estejam presentes medidas e conjuntos críticos. Neste contexto, esta dissertação propõe uma nova metodologia de análise de observabilidade baseada no estimador linearizado regularizado e apresentam duas técnicas de classificação de medidas capazes de identificar medidas críticas, medidas pertencentes a conjuntos críticos e medidas redundantes. A primeira técnica é baseada na fatoração da matriz Gram das medidas e a segunda é baseada na fatoração da matriz Jacobiana das medidas. Além disso, são estudadas e aplicadas técnicas de fatoração com números inteiros que conferem maior robustez 'as metodologias de classificação de medidas. São apresentados testes realizados em redes de pequeno e médio porte que apontam o bom funcionamento dos métodos desenvolvidos e estudados / Abstract: In planning of power systems state estimation are defined the type, the location and the number of meters. An adequate measurement plan have to ensure the observability of the network, enabling the state estimation of the entire network, and allow filtering of gross errors. In order to filter gross errors is necessary in the measurement plan is not present critical measurements and critical sets. In this context, this work proposes a new observability analysis methodology based on the regularized weighted least squares DC state estimator and presents two measurements classification techniques capable of identifying critical measurements, measurements belonging to critical sets and redundant measurements. The first technique is based on the factorization of the measurement Gram matrix and second is based on the factorization of the measurement Jacobian matrix. Furthermore, are studied and applied factorization techniques with integers numbers which give greater robustness to measurements classification methodologies. Tests are presented in small and medium networks size showing the proper functioning of developed and studied methods / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

Power system maintenance optimisation involves obtaining the minimum total costs, including preventive and corrective maintenance costs and the cost of failures for both supplier and customer. To calculate the cost of failure, information is needed about the equipment reliability characteristics. It is also necessary to know how maintenance affects component reliability. The aim of the work leading up to this thesis has been to develop reliability models that include the effect of maintenance. Three case studies have been carried out for different types of power system components using three distinct methods. In the first study the reliability of the first generation XLPE cables was modelled with respect to failures caused by water treeing using load-strength modelling. The model was based on assumptions of the ageing process and the distribution system characteristics. This study showed that it is possible to and overvoltage and insulation characteristics that can be fitted to agree with failure statistics for water tree ageing in XLPE cables. The second case study included a study of all circuit breaker failures in the Swedish transmission grid during the period from 1 January 1999 to 30 June 2003. In a subsequent investigation a method to combine information from the design process with maintenance records and failure statistics was employed using Bayesian methods. The resulting reliability model is continuously updated as more failure and maintenance data becomes available. This case study showed that it is possible to develop reliability models for components that have not yet failed by utilising information from the design process and right-censored observations from inspections. Finally, in the third case study a quantitative method for establishing the condition of disconnector contacts by the use of thermography was developed. Two sets of measurements on disconnector contacts in the Swedish transmission grid were carried out to establish the accuracy of the method. By utilising the results from the measurements estimates of the statistical distributions of the error sources were produced. The results from the case studies show that the lack of detailed, high-quality data remains a critical problem when modelling reliability of power system equipment, even when using methods that require a minimum of data. / QC 20101209

This master thesis is done within the Energy Systems Engineering program at Uppsala University and performed for CorPower Ocean. Wave energy converters (WECs) are devices that utilize ocean waves for generation of electricity. The WEC developed by CorPower Ocean is small and intended to be deployed in an array. Placed in an array the different WECs will interact hydrodynamically and the combined power output is altered. The aim of this thesis is to model and investigate how the array configuration affects the electric power output. The goal is to target an optimal array layout for CorPower Ocean WECs, considering both average power and power smoothness in the optimization.   In this thesis multiple buoys have been implemented in the time-domain model at CorPower Ocean. The hydrodynamic interactions are computed using an analytical interactions theory together with a recently developed calibration method able of handling WEC bodies of complicated shapes. The array behavior in regular waves is analyzed and it is identified how the beneficial separation distances vary with wave length. It is observed that the best separation distances for high average power does not exactly correspond to the best for minimizing the peak-to-average power. Simulation results show that it is possible to obtain both high average array power as well as increased power smoothening in a regular wave. A genetic algorithm for optimizing the array configuration is designed and tested for two different array patterns. Initial simulations are conducted in realistic multi-directional irregular waves. The power smoothening capacity of the array remains even in these conditions but the exact extent of it is still uncertain.   This thesis delivers a WEC array simulation model as well as an initial view on the array characteristics of the phase controlled CorPower Ocean WEC. Additionally, it demonstrates an optimization algorithm taking both average power and power smoothness into account.

Small satellites and CubeSats have established themselves within the aerospace community because of their low cost and high return on investment. Many CubeSats are developed in a short time frame and often leverage commercial off the shelf components for quick turnaround missions. With regard to the Electrical Power System, commercially available products typically use a centralized architecture. However, a centralized architecture is not reusable, since missions that require additional solar arrays or batteries would necessitate a redesign of the power system. With the range of CubeSat sizes and mission goals, it is obvious that a one-size-fits-all solution is not appropriate. This thesis details a reusable and scalable power system architecture applicable to a variety of missions. Reusability is achieved by using common building blocks or "modules," where the same modules can be used between missions. Scalability is achieved by not limiting the number of modules that can be connected together—more modules can be added as needed. In this system, solar arrays and battery units connect directly to a common bus, supplying an unregulated voltage to each subsystem. These subsystems then regulate the bus voltage to their individual needs. The power system also features direct energy transfer and solar-only operation.