O setor elétrico é um setor de natureza estratégica para qualquer nação, na medida em que na era moderna a eletricidade é um insumo fundamental para a qualidade de vida das pessoas e para o desenvolvimento e a produção da indústria, sendo mesmo considerado como uma mola mestra da economia do país. Em função dessa importância, crescente ao longo do tempo e aguçada em decorrência de restrições de disponibilidade e de cunho ambiental para a utilização massiva do petróleo, o setor elétrico deve ser planejado com extrema atenção e de forma muito criteriosa, posto que sua expansão necessite estar garantida e se trata de um setor intensivo em capital e com empreendimentos de longo prazo de maturação, particularmente no caso dos grandes aproveitamentos hidrelétricos e as plantas nucleares. Dentro desse contexto, o presente trabalho buscou endereçar a temática de planejamento de sistemas elétricos, aproveitando a experiência profissional pregressa da autora, especialmente no que tange às vertentes de estudos tarifários e de mercado, como também pelo fato de conhecer em algum detalhe os marcos regulatórios e o funcionamento dos setores elétricos no âmbito do Mercosul. Nesse sentido, o presente trabalho apresenta uma análise crítica comparativa de modelos tarifários, dos sistemas de transmissão, atualmente vigentes em alguns países da América do Sul. As recentes tendências políticas e energéticas dos países considerados constituem-se em importantes sinais para o estabelecimento de futuras negociações na área elétrica. Isso propicia a realização de um estudo referente às condições tarifarias e regulatórias destes mercados. Questões técnicas em projetos deste tipo poderiam ser superadas, porém, eventuais divergências regulatórias e tarifarias entre os mercados elétricos poderiam adiar ou até mesmo inviabilizar os referidos projetos. Por outro lado, levando em conta o nexo existente entre o estudo dos modelos tarifários, os sinais de possíveis negociações de energia e a expansão do sistema, apresentam-se também uma análise comparativa entre as metodologias de previsão utilizadas no cálculo da demanda de energia elétrica nos países considerados. As referidas metodologias de previsão, sobre as quais foram utilizados o histórico de consumo do Brasil (1996-2006) e as variáveis explicativas inerentes a cada modelo, correspondem às classes de consumo Residencial, Industrial, Comercial e Rural; responsáveis por aproximadamente 90% do consumo nacional. Foram encontradas certas semelhanças principalmente no relacionado às variáveis econométricas utilizadas por estes modelos, os quais se refletiram nos resultados obtidos. / The electric power sector is an area of strategic nature for any country as electricity is an essential product for both the quality of life and the development of the industry. This reason led to consider it as a sound foundation for the economy development and GNP growing. Because of its role, which grows along time even due to the restrictions of availability and environmental issues for the massive use of oil, the electric sector must be carefully planned as its expansion needs to be guaranteed. This sector embraces large capital and long-term investments, particularly those related to hydroelectric projects and nuclear plants. Within that framework, this work aims at to address the electric power planning subject using the author\'s past knowledge related to electric tariffs as well as on the regulatory framework and market operation of the Mercosul. A critical comparative analysis of transmission tariff models currently applied in some South American countries is particularly addressed. The recent political and energy policy trends of the considered countries appear as important signals for the establishment of future negotiations of electricity. This situation demands the realization of new studies related to both tariff and regulatory conditions in these markets. Technical issues in projects of this kind may well be overcome; however, some regulatory differences and even tariff model differences among marketers could delay or even turn unfeasible the referred projects. On the other hand, considering issues like the link existing among the transmission pricing models adopted and the likely electricity trading as well as the system expansion, a comparative analysis of the methodologies used to forecast the energy demand in the South American countries previously considered, is also presented. Such forecast methodologies, upon which were applied the annual electricity consumption in Brazil in the period 1996 through 2006 as well as the explanatory variables inherent to each model, correspond to the Residential, Industrial, Commercial and Rural consumptions, responsible for nearly 90% of the national consumption. From this analysis, some similarities mainly those related to the econometric variables used by each methodology were found. Such similarities and related findings are reflected in the results presented.

Made available in DSpace on 2016-08-17T14:53:10Z (GMT). No. of bitstreams: 1 Aryfrance Rocha.PDF: 1042995 bytes, checksum: 91f3c0dd1f6d851ec15f8046276540d7 (MD5) Previous issue date: 2007-03-19 / Some methods of fault location in transmission lines have been considered in literature, of which we detach the methods based on the crossed correlation, transformed wavelet and the use of neural networks. This work presents an alternative method based upon of independent components analysis (ICA) to localize the distance at which singlephase, two-phase, two-phase grounding and three-phase faults occur in a 500 kV transmission systems starting from different angles of fault incidence at different distances along the line together with fault signals or traveling waves subject to other perturbations unrelated with the desired fault signal at the fault distance placement. Simulations results of a 500 kV high voltage transmission system got with the software Alternative transients program (ATP) show that the proposed methodology implemented with Matlab is a rather efficient tool for various fault types location. / Vários métodos de localização de faltas em linhas de transmissão têm sido propostos na literatura, dos quais podemos destacar os métodos baseados na correlação cruzada, na transformada wavelet e no uso de redes neurais. O objetivo deste trabalho é mostrar um método alternativo baseado na utilização de análise de componentes independentes (ICA) para localizar a distância de faltas monofásicas, bifásicas, bifásicasterra e trifásicas em um sistema de transmissão de 500 kV, a partir de diferentes ângulos de incidência de falta em diferentes distâncias ao longo da linha de transmissão e com os sinais de faltas ou ondas viajantes submetidas a outras perturbações não correlacionadas com o sinal de falta desejado na localização da distância da falta. De acordo com os resultados obtidos com a simulação de um sistema de transmissão de 500 kV de alta tensão pelo software ATP (Alternative Transient Program) mostram que a metodologia proposta implementada através do software Matlab é uma ferramenta bastante eficiente na localização de faltas para todos os tipos de faltas.

A recém-adquirida competitividade pela energia eólica frente a outras fontes alternativas e, até mesmo, convencionais tem sido comemorada pelo setor de energia elétrica. No entanto, a base para essa comparação leva em conta apenas os parâmetros dos investimentos do parque viabilizado, não sendo considerados outros fatores inerentes à inserção da fonte na matriz, como, por exemplo, o aumento do risco ao sistema, investimento necessário à ampliação da Rede Básica para escoamento da energia para o centro de carga e os custos com redespacho de geração, reserva girante e controles do sistema. O maior potencial está concentrado no Nordeste e o maior centro de carga no Sudeste, assim, em caso de exploração intensiva do potencial da fonte, será necessário passar por grandes investimentos em reforços e ampliações da rede básica. A partir desse panorama, busca-se realizar as primeiras análises de sensibilidade sobre a eficiência econômica dos parques eólicos instalados no Nordeste e, ao mesmo tempo, analisar as condições de atendimento da ponta. / The newfound competitiveness in wind power compared to other alternative and even conventional energy sources has been celebrated by the electric power sector. However, the basis for this comparison takes into account only the parameters of the Capex, not considering other factors inherent in the insertion of the source in the array, for example, increase the risk to the system, expansion of the investment necessary for Basic network for transport of energy to the load center and the cost of redispatch generation, spinning reserve, and system controls. The greatest potential is concentrated in the Northeast and the largest load hub in the Southeast, so, in case of intensive exploitation of the potential of the source, large investments in reinforcements and expansions of the grid will be necessary. From this overview, we attempt the firsts sensitivity analysis on the economic efficiency of wind farms in the Northeast and the load peak supply conditions.

Orientador: Yuzo Iano / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-25T18:19:06Z (GMT). No. of bitstreams: 1 Carvalho_SilvioRenatoMessiasde_D.pdf: 5536147 bytes, checksum: dc9993f46cee4460fcc98052fbf1a1bf (MD5) Previous issue date: 2014 / Resumo: Este trabalho apresenta uma nova proposta para o conceito de redes de frequência única, SFN. Redes de radiodifusão em SFN são assim chamadas por utilizarem um único canal de transmissão ou uma única frequência. Nesta proposta os transmissores de uma rede SFN são conectados formando uma rede real que por sua vez se interliga a pontos receptores chamados de pontos monitores estrategicamente localizados dentro da área de cobertura. Uma rede de radiodifusão que possa se adaptar dinamicamente às variações das condições do canal é útil porque aumenta a confiabilidade da rede. A modificação proposta apresenta vantagens para as emissoras de televisão que possuam redes de retransmissão destinadas a ampliar sua cobertura em uma área regional com várias cidades obtendo um ambiente de rede muito mais controlado e seguro. O conceito também pode ser aplicado a gap-fillers e repetidores de mesmo canal on channel. O trabalho apresenta simulações de cobertura para mostrar as variações do canal e a resposta da rede / Abstract: This paper presents a new approach for the concept of single frequency networks, SFN. SFN broadcasting networks are so named because they use a single transmission channel or a single frequency. In this proposal the transmitters in a SFN network are connected together to form a real network that in turn connects to receptor sites called 'monitor point' strategically located within the coverage area. A broadcasting network that can dynamically adapt to changing channel conditions is useful because it increases network reliability. The proposed modification has advantages for television stations that have relay stations aiming to expand its coverage in a regional area with a network more controlled and secure. The concept can also be applied to gap- fillers and repeaters on channel. This work presents simulations of coverage to show variations in channel and network response / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

This diploma thesis deals with the development of the Polish power sector since the introduction of the first energetic law with the orientation on the electricity. It describes the development of the production sector, the distribution sector and the transmission sector. It is devoted also to the privatisation of the subjects that act on this market. This thesis deals with the development of the cross border auctions with the neighbouring countries, concretely the Czech Republic, Slovakia and Germany. It tracks the development of the offered amounts of the capacities from the shortterm and longterm perspective. It describes the issue connected with the longterm contracts of the Polish transmission operator and its whole function on the market. It tracks down the electricity price development from the year 2000, it mentions the recent electricity prices of the Polish market and deals with the possible future price development.

Customers expect electricity to be not only available but also affordable whenever they need it. Due to the stochastic nature of power system component failure, the management of power interruption is challenging. Although the reliability of supply can usually be increased by employing redundant equipment; this means that affordability is compromised. At present, many power utilities have a considerable amount of aged equipment in their networks. Although they have already started replacement planning, the price control schemes imposed by regulatory authorities constrain their capital expenditure budget. This thesis has studied the influence of the end-of-life failure of power transformers on transmission system reliability in order to make decisions on their replacement. Power transformers are selected for the analysis because they are technically complex, expensive, and main feed points of electricity for end users. In addition, surveys on ageing asset show that 50% of transformer populations, in many utilities, have been classified as old since the year 2008. The focus of these reliability analyses is to identify the most critical transformers and to establish a reliability based replacement framework. Modelling of end-of-life failure was reviewed, and the state-of-the-art method of its incorporation into system reliability was adopted. A reliability assessment tool within DIgSILENT PowerFactory package was developed in order to perform reliability studies. This thesis has four original contributions surrounding transmission system reliability analysis. The first contribution is the development of a cost-effective framework that concerns the application of reliability studies on asset replacement decision making. The developed framework has employed reliability importance measures, the Pareto analysis and economic comparison based on reliability incentive/penalty schemes. All the three elements of the framework are original applications to system reliability area. The second contribution is the integration of unconventional end-of-life failure models into system reliability. The unconventional model used in this study is Arrhenius-Weibull distribution, which characterises end-of-life failure under different loading conditions. This study has evaluated the added value provided by including loading levels in failure models and how this enhances the understanding of the effect of operational factors on system reliability. The third contribution is the investigation of dependent failure of power transformers caused by thermal stress. This investigation has led to the development of two probabilistic indicators to rank power transformer based on their criticality to multiple failure events. These new indicators have related the transformer reliability to its age and loading levels. In the fourth contribution, comprehensive studies of the effect of uncertainty associated with failure model parameters were performed. The first study has established bases for a system related approach for refining failure models. The approach is based on assessing the sensitivity of the system reliability or the system reliability applications to the uncertainty in failure model parameters. In the second study, two quantification methods were adopted to propagate the uncertainty in failure model parameters to system reliability indices. These are the second order probability and evidence theory. The last uncertainty study has described the use of sampling based sensitivity analysis to identify the most critical transformers and their area of vulnerability. Studies throughout the thesis have been performed on a realistic transmission network and the IEEE Reliability Test System.

The aim of master thesis is to analyze the impact of electricity generation from wind on investment activities of CEPS's company, and also to assess the impact of these investments on the Czech economy. The work familiarizes readers with reasons for the development of the transmission system in the Czech Republic, with the concept of blackout and also with apparatus of assessing the impact of investment on the economy of the selected state -- input-output model analysis. The method used to obtain data for this work is based on the literature review, as well as expert advice on the input-output model, consultation with the experts in CEPS and the data provided by them. The theoretical part deals with Czech transmission system, and it is followed by the development of wind energy construction and the problems associated with it, with blackout and readiness of the Czech Republic to the possible failure in electricity supply. In the practical part, there are measures that are built in order to prevent the risk of blackouts in the Czech Republic, there is a more detailed examination of the Plan of development and rehabilitation of Czech transmission system, and there is also described the process of construction of analytical input-output apparatus for analyzing the impact of CEPS's development investments on the Czech economy, approximated by GDP.

This thesis deals with energetical and efficiency comparison of two tractor transmission types, used by the Zetor company. The description of transmission construction types of various tractor producers is given, with focus on Zetor tractors transmission construction. The laboratory methodology and operating tractor and tractor sets measurement is described. The individual results are introduced in tables and graphs and subsequently evaluated.

Orientador: Sérgio Kurokawa / Banca: Jean Marcos de Souza Ribeiro / Banca: Edson Guedes da Costa / Resumo: Entre tantas tecnologias alternativas desenvolvidas ao longo das últimas décadas, procurando aumentar a eficácia das técnicas convencionais ou propondo novas técnicas não convencionais na transmissão da energia elétrica a longas distâncias e lugares de difícil acesso, o estudo proposto apresenta alguns conceitos e características para sistemas de transmissão constituídos por quatro fases genéricas. O sistema de transmissão tetrafásico tem sido tema de diversos estudos e aplicações em alguns países da Europa e Ásia, apresentando algumas vantagens quando comparado ao sistema de transmissão trifásico convencional. Esse sistema pode ser facilmente integrado ao sistema trifásico por meio de transformadores, amplamente abordado por diversas referências bibliográficas. Nesse estudo foi realizado uma análise comparativa das possíveis sobretensões ocorridas nos domínios da frequência e do tempo entre os sistemas de transmissão trifásico e tetrafásico, avaliando as características elétricas e as respostas transitórias eletromagnética e impulsiva, mostrando novas vantagens sobre esta tecnologia, fornecendo uma avaliação completa sobre o tema / Abstract: Among the many alternative technologies developed over the past decades, seeking to increase the effectiveness of conventional techniques or proposing new non-conventional techniques in the transmission of electricity over long distances and places of difficult access, the proposed study presents some concepts and features to transmission systems that are constituted of four generic phases. The four-phase transmission system has been subject of numerous studies and applications in some countries in Europe and Asia, presenting some advantages compared to the conventional three-phase transmission system. This system can be easily integrated into the three-phase system through transformers, thoroughly approached by several bibliographical references. In this study was made a comparative analysis of the possible overvoltages that occurred in the areas of frequency and time between the transmission systems of three-phase and four-phase, evaluating the electrical characteristics and the transient answers, electromagnetic and impulsive, showing new advantages over this technology, providing a complete evaluation of this issue / Mestre

Thyristor switched capacitors (TSCs) have found an ever increasing role in the operation of flexible AC transmission systems or FACTS. The ability of these static var compensators to regulate the voltage by consuming or supplying reactive power quickly is not only viable for transmission but is an effective measure for increasing power quality at a distribution level. The proposed design uses a variable number of logically switched capacitors to supply reactive generation per reactive demand. The design ensures that the capacitors are safely switched into service, reactive demand is accurately calculated, and the TSC will respond quickly to changes in demand. While providing fast and safe operation, the conceptual design is also flexible enough to allow for optimization of the TSC to meet the demands of specific loads.