• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 199
  • 70
  • 27
  • 21
  • 16
  • 14
  • 6
  • 5
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 445
  • 445
  • 159
  • 128
  • 88
  • 78
  • 73
  • 70
  • 68
  • 65
  • 60
  • 57
  • 53
  • 48
  • 43
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Optimisation algorithmique et modèles aléatoires d'un système électrique de cogénération : application au système électrique au Liban / Algorithmic optimization and random models of a cogeneration system : application to the libanese electric system.

Al asmar, Joseph 16 September 2015 (has links)
Les systèmes de cogénération (SC) sont largement définis par la production simultanée ou coïncidente de la production combinée de chaleur et d'électricité. L’idée de la cogénération revêt une importance particulière puisqu’elle est un outil de réduction des émissions à effet de serre. Comme les systèmes électriques ont été développés selon les carburants et leur utilisation énergétique, de même, les SC ont été développés afin d'utiliser l'énergie possible du carburant pour produire de l’électricité et de la chaleur. La décentralisation de la production électrique est désormais un événement existant. La favorisation maximale de l’électricité d’origine renouvelable ou des systèmes de
cogénération, a abouti à cette décentralisation formant une partie de la production électrique.
Cette thèse est appliquée au cas du système électrique libanais. Elle sert à évaluer la puissance optimale de cogénération qui doit être installée par le secteur public ou le secteur privé, ainsi que la mise en évidence des impacts économiques et environnementaux dus à l’intégration des SC et des énergies renouvelables dans le réseau. Dans ce travail de thèse, nous nous sommes intéressés à l’intégration des systèmes de cogénération dans un réseau électrique. Nous avons travaillé sur deux thèmes principaux et les avons appliqués au cas du réseau électrique libanais. Le premier thème principal est l’innovation d’une stratégie de prise de décision qui sert à trouver une puissance de cogénération respectant l’économie et l’environnement. Le second thème principal est l’optimisation et le contrôle du réseau électrique en fonction des énergies renouvelables (ER) et des SC intégrés. Les deux thèmes cités sont ensuite appliqués au cas du réseau électrique libanais pour montrer les avantages de l’intégration des SC et des ER dans ce réseau. / Cogeneration systems (CS) are largely defined by the simultaneous or coincident production of combined heat and power. The idea of cogeneration is of particular importance since it is a tool for reducing greenhouse gases emissions. As electrical systems have been developed according to the fuel and energy use, the CS have been developed to profit from the possible potential of the fuel energy to produce electricity and heat. Decentralization of power generation is considered an important fact. The maximum use of electricity from renewable sources or cogeneration systems, has leaded to the decentralization of power generation.This thesis is applied to the Lebanese electrical system. It is used to assess the optimum cogeneration power to be installed by the public sector or the private sector, as well as highlighting the economic and environmental impacts due to the integration of the CS and renewables into the grid. In this thesis, we focused on the integration of cogeneration systems into a grid. We worked on two major themes and have applied them to the case of the Lebanese electrical grid. The first main theme is the innovation of a new decision making strategy to find the cogeneration power respecting the economy and the environment. The second main theme is the optimization and the control of the electrical grid due to the integration of renewable energy (RE) and CS. The two themes cited are then applied to the case of the Lebanese electrical grid to show the benefits of the integration of RE and CS into this grid.
242

Cyber sécurité des systèmes industriels pour les smart-grids : détection d'intrusion dans les réseaux de communication IEC 61850 / Cyber security of smart-grid control systems : intrusion detection in IEC 61850 communication networks

Kabir-Querrec, Maëlle 28 June 2017 (has links)
Les systèmes de contrôle et d'automatisation industriels (IACS - Industrial Control and Automation Systems) reposent largement et de plus en plus sur les Technologies de l'Information et de la Communication. A l'origine, les IACS utilisaient des protocoles propriétaires sur des réseaux fermés, assurant ainsi une sécurité par obscurité et isolement. Mais les technologies et les usages ont évolué et cette sécurité intrinsèque n'existe plus désormais. Cette évolution concerne entre autre le domaine électrique : le réseau électrique devenant le "smart grid".Le standard IEC 61850 est un pilier pour le développement du smart grid. Il a pour objectif de rendre possible l'interopérabilité dans les "Systèmes et réseaux de communication pour l'automatisation des services de distribution d'énergie". Pour cela, la norme définit un modèle de données commun ainsi qu'une pile de protocoles répondant à divers besoins de communication.Le standard IEC 61850 n'aborde pas la question de la cyber sécurité malgré une prise de conscience générale qu'un risque cyber pèse sur les IACS.Ces travaux de recherche proposent de répondre à cette question de la cyber sécurité par de la détection d'intrusion dans les réseaux IEC 61850, et plus précisément dans les communications temps-réel GOOSE. L'idée est d'exploiter au maximum les sources d'informations que sont les spécifications du protocole et la configuration du système pour développer un système de détection d'intrusion réseau (NIDS - Network Intrusion Detection System) sur mesure. Cette approche comportementale déterministe est un gage de précision de détection.Ce manuscrit compte quatre chapitres. Les deux premiers consistent en un état de l'art détaillé sur les NIDS pour les IACS d'une part, et l'analyse du risque cyber d'autre part. Les deux autres chapitres présentent les contributions proprement dites de ces travaux de thèse. Le chapitre 3 explore tout d'abord le risque cyber pesant sur un poste électrique et pouvant compromettre la sûreté de fonctionnement du système. Dans un deuxième temps, est proposée une extension du modèle de données IEC 61850 dédiées à la détection d'intrusion dans les communication GOOSE. Le chapitre 4 commence avec la démonstration expérimentale de la faisabilité d'une attaque de type injection de données sur le protocole GOOSE, puis explique comment utiliser les fichiers de configuration du système pour spécifier les règles de détection. Un analyseur syntaxique pour le protocole GOOSE a été intégré à l'analyseur de trafic open source Bro, permettant l'implémentation d'un algorithme de détection. / Information and Communication Technologies have been pervading Industrial Automation and Control Systems (IACS) for a few decades now. Initially, IACS ran proprietary protocols on closed networks, thus ensuring some level of security through obscurity and isolation. Technologies and usages have evolved and today this intrinsic security does not exist any longer, though. This transition is in progress in the electricity domain, the power infrastructure turning into the "smart grid".The IEC 61850 standard is key to the smart grid development. It is aimed at making interoperability possible in ``Communication networks and systems for power utility automation''. It thus defines a common data object model and a stack of protocols answering different purposes.Although the cyber risk in IACS is now widely acknowledged, IEC 61850 does not address cyber security in any way whatsoever.This work tackles the question of cyber security through network intrusion detection in IEC 61850 networks, and more specifically in real-time GOOSE communications. The idea is to get the most out of the protocol specifications and system configuration while developing a tailored NIDS. This enables detection accuracy.
243

Optimisation des réseaux : réseau actif et flexible / Networks optimization : active and flexible network

Touré, Sellé 20 October 2014 (has links)
Le Système Électrique est soumis ces dernières années à plusieurs évolutions, depuis la dérégulationdu marché d'énergie à l'intégration de plus en plus importante de Générateurs Dispersés (GED). Ainsi,dans le cadre du concept de Smart Grid, les nouvelles technologies de l'information et de lacommunication (NTIC) offrent de nouvelles perspectives pour la gestion et l'exploitation des réseauxde distribution.Dans ce contexte, de nouveaux outils sont étudiés. Encore appelés Fonctions Avancéesd’Automatisation (FAA), le but principal de ces outils est d’utiliser tous les composants du réseau dedistribution de manière coordonnée en vue de les rendre plus actifs, flexibles et d’augmenter leurefficacité opérationnelle. Dans notre cas, nous avons étudié les fonctions associées à la reconfigurationen régime normal, du réglage de la tension et l’hybridation de ces deux derniers, tout en tenant comptede la présence des GED. En partant du comportement physique inhérent aux composants du réseau,plusieurs modèles ont été proposés. Certains sont tirés de la théorie des graphes et d’autres sur l’outilpuissant de la reformulation mathématique pour « convexifier » nos modèles. Cette modélisationadoptée répond à la fois à la nécessité de prendre en compte tous les moyens de réglages qui peuventêtre discrets (prises des transformateurs avec régleurs en charge ou des gradins de condensateurs),binaires (état de connectivité des composants) et continues (puissance réactive de la DG) et par lechoix des outils et des algorithmes d'optimisation mixte. En effet, la complexité de ces problèmes sonttelles que nous avons exploré à la fois des algorithmes méta-heuristiques (ACF : Algorithme desColonies de Fourmis) que déterministes (Décomposition de Benders Généralisée, Algorithme duBranch and Cut). / The Electric Power System is undergoing a lot of evolutions in recent years, including the energymarket deregulation and the increasing integration of Dispersed Generators (DG). Therefore, withinthe framework of Smart Grid concept, the New Information and Communication Technologies (NICT)provide new perspectives to manage and operate distribution networks.In this context, new tools, called Advanced Distribution Automation functions (ADA, are beingstudied). The main objective of these tools is to use all the distribution network components in acoordinated manner to make them more active and flexible, in addition to increasing their operationalefficiency. In our case, we studied the functions associated with the reconfiguration problem, thevoltage control problem and the hybridization of these two, while taking into account the presence ofthe DG. Based on the inherent components of network physical models, several models have beenproposed. Some are derived from the graph theory and others use powerful mathematicalreformulation to make our models convex. The adopted models answer to the necessity of taking intoaccount all regulation means, which can be discrete (On Load Tap-Changer and capacitor banks),binary (components connectivity such as lines or transformers) and continuous (DG reactive power ),and by the choice of tools and algorithms of mixed optimization. Indeed, the complexity of theseproblems is such that we have explored both algorithms: meta-heuristic (ACA, Ant Colony Algorithm)and deterministic (Generalized Benders Decomposition, Branch and Cut Algorithm).
244

Protetor de redes inteligente e relé digital com tecnologia nacional integrando proteção, controle, telecomando e monitoramento viabilizando smart grid e geração distribuída a partir dos sistemas de distribuição subterrâneos nas grandes metrópoles / Inteligent Network Protectror with Digital Relay integrating Protection, Control and Monitoring enabling Smart Grid and Distributed Generation in Large Cities with underground Distribution Systems

Humberto de Alencar Pizza da Silva 28 April 2011 (has links)
A importância das novas tecnologias de informação, automação, monitoramento e sistemas eletrônicos inteligentes têm aumentado significativamente nos últimos anos. Essas tecnologias desempenham um papel fundamental na sociedade moderna e contribuem de forma decisiva para a resolução de importantes desafios para uma sociedade que quer ser mais próspera, internacionalmente competitiva, saudável, segura e sustentável. Como eixo de \"inovação\", essas tecnologias são fatores importantes para todos os setores produtivos da economia. O motor destas tecnologias, entretanto, é a energia, particularmente a eletricidade. Assim, em uma sociedade cujo estilo de vida é fortemente dependente dela, desenvolver tecnologias que permitam não somente a geração, mas também a distribuição de energia de forma barata e limpa e que garantam seu fornecimento ao longo do tempo com a máxima eficiência é uma questão prioritária. Os sistemas baseados em redes inteligentes (do inglês: Smart Grid) vêm, justamente, atender a esses requisitos, representando o que há de mais moderno no setor elétrico, com aumento e diversificação de fontes de geração distribuída na forma de pequenos geradores, maior interação consumidor-distribuidor de energia, integração de diferentes fontes de geração renováveis (ex.: solar, eólica etc.). O cenário energético nacional está avançando de forma muito rápida. Nas distribuidoras, o foco claramente está na redução de perdas comerciais e de custos operacionais, principalmente por meio da modernização dos ativos e da crescente instalação de dispositivos eletrônicos inteligentes nos clientes de baixa tensão (ex.: medidores eletrônicos, dispositivos eletrônicos inteligentes para monitoramento e diagnóstico, relés digitais etc.). Esta tese de doutorado apresenta uma solução com tecnologia nacional que disponibiliza todos os benefícios do Smart Grid através dos equipamentos mais importantes e estratégicos presentes na topologia das Redes de Distribuição Subterrânea Secundária Trifásica: os Protetores de Redes. A partir do centro nevrálgico das Redes de Distribuição Subterrâneas (RDS), cuja topologia está presente nos centros de alta concentração de carga das principais metrópoles do Brasil, a solução desenvolvida pode viabilizar técnica e economicamente a modernização da automação da RDS, com tecnologia nacional de baixo custo, proporcionando igualmente a incorporação dos avanços do Smart Grid e da Geração Distribuída. Este salto tecnológico significaria para as distribuidoras de energia elétrica entre outros benefícios: Melhor controle do processo para uma melhor otimização da rede, desde integração das intermitentes fontes renováveis até uma interação mais dinâmica com os consumidores; Maior flexibilidade às concessionárias em relação ao uso da energia para atingir o grande objetivo social de redução do efeito estufa e otimização do consumo de energia reduzindo perdas e desperdícios; No curto prazo, os benefícios diretos da melhoria do gerenciamento da indisponibilidade, gerenciamento otimizado dos ativos e do capital, melhoria no planejamento, processos e serviços de fornecimento e usos finais de energia, aumento de eficiência de manutenção, redução de perdas técnicas e comerciais, otimização do investimento na compra de novos protetores com menores custos podendo superar a demanda reprimida pelos altos custos de alternativas importadas. / The importance of new technologies in the field of, automation, monitoring, information technology and electronic systems have increased significantly in recent years. These technologies play a basic role in the modern society and contribute of decisive way for the resolution of important challenges for a society that is in search of a more prosperous life, internationally competitive, healthful, safe and sustainable. As a key of \"innovation\", these technologies are key factors for all the productive sectors of the economy in the society. The fuel for the engine of these technologies, however, is the energy, particularly the electricity. Thus, in a society whose life style is strongly dependent of electricity, to develop technologies that not only allow the generation, but also the distribution of energy in a cheap and clean way and which could guarantee its supply throughout the time with the maximum efficiency is a priority issue. The systems based on intelligent networks fully meet these requirements, representing what there is of most modern in the electric sector. The Brazilian energy scenario is quickly changing over the recent years toward modernization, with more distributed generation, in the form of smaller generators, more customer interaction, the integration of more variable resources such as wind and solar, and more renewables overall. For the Power Utilities, especially in the Distribution Sector, the focus is clearly in the reduction of commercial losses and operational costs, mainly by means of the modernization of the assets and an increase in the installation of intelligent electronic devices at consumers side (e.g.: electronic energy meters, intelligent electronic devices for condition monitoring, digital relays etc.). This work presents a solution developed based on Brazilian technology that incorporates all the benefits of smart grid to the most important equipment that is present in the topology of the Low-Voltage Secondary Network Distribution System: the Network Protector. From the neuralgic center of these Low-Voltage Secondary Network Systems, which topology is used in the most important cities in Brazil, which has a high load concentration, the solution presented here make it feasible technically and economically the use of smart grid topology profiting from its great benefits such as: Allow utilities to better optimize the grid to support a number of public policies, from intermittent renewable integration to more dynamic interfaces with customers; Offer utilities more flexibility relative to how they use energy toward the greater societal objectives of reducing greenhouse gases and energy consumption. In the short and mid term, a smarter grid offers utilities operational benefits (outage management, improved processes, maintenance and workforce efficiency, reduced losses, etc.) as well as benefits associated with improved asset management (system planning, better capital asset utilization, etc.), lower investment to acquire new Network Protectors.
245

Estudo de geração fotovoltaica distribuída: análise econômica e o uso de redes neurais artificiais / Distributed photovoltaic generation: economic analysis and the use of artificial neural networks

Alves, Ricardo Henrique Fonseca 09 March 2017 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-07-05T12:29:15Z No. of bitstreams: 2 Dissertação - Ricardo Henrique Fonseca Alves - 2017.pdf: 7774118 bytes, checksum: a675bf30443ae9eb20be6a3e5623bb4a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-07-10T14:30:07Z (GMT) No. of bitstreams: 2 Dissertação - Ricardo Henrique Fonseca Alves - 2017.pdf: 7774118 bytes, checksum: a675bf30443ae9eb20be6a3e5623bb4a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-07-10T14:30:07Z (GMT). No. of bitstreams: 2 Dissertação - Ricardo Henrique Fonseca Alves - 2017.pdf: 7774118 bytes, checksum: a675bf30443ae9eb20be6a3e5623bb4a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-09 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The main goal of this work is to propose a methodology for the selection of 51 consumers in Nova Veneza-GO connected to two transformers in the pre-Smart Grid network. The methodology consists of ten stages ranging from the grouping of consumers with the same power consumption profile using a neural network, that is, a Non Parametric Self-Organizing Map (PSOM), until the complete and optimal allocation of financial resources through of an Integer Linear Programming. We obtained 12 different groups (clusters) of consumers of the two transformers with the same power consumption profile using the network PSOM algorithm. This grouping (clustering) was considered in the dimensioning and design of Photovoltaic Systems Connected to the Grid (Grid-Tie Systems) using three different computational tools, among them, an approach based on the PVSyst software, trial version V6.39. In addition, a study of Economic Engineering was carried out to expand the R&D pilot project aiming at the implementation of Grid Tie Systems for all the consumers of Nova Veneza-GO and Goiânia-GO, considering consumption data available by Celg-D and also considering two different scenarios based on the implementation of photovoltaic systems with and without government incentive. An Economic Engineering analysis was performed considering that 1%, 5%, 10%, 20%, 30% and 100% of Consumer Units (UC) adhere to the implantation of solar systems in Goiânia-GO. Environmental results were found for the city of Nova Veneza-GO and Goiânia-GO, evidencing an expressive reduction in CO2 emissions and a great saving of water. / O principal objetivo deste trabalho é propor uma metodologia para a escolha de 51 Unidades Consumidoras (UC) em Nova Veneza-GO ligados a dois transformadores pertencentes a uma rede pré Smart Grid localizada na cidade. A metodologia consiste de dez etapas que vão desde o agrupamento de consumidores com mesmo perfil de consumo de energia elétrica utilizando uma rede neural PSOM (do inglês: Non Parametric Self-Organizing Map), incluindo a realização de alocação de recursos financeiros de forma otimizada por meio de Programação Linear Inteira. Utilizando a rede PSOM, foi possível agrupar os consumidores dos dois transformadores em 12 grupos distintos com mesmo “perfil de consumo”. Esse agrupamento foi importante para o dimensionamento de Sistemas Fotovoltaicos Conectados à Rede Elétrica (Sistemas Grid-Tie) utilizando diferentes ferramentas computacionais, dentre elas, o software PVSyst na versão trial V6.39. Adicionalmente, foi feito um estudo de Engenharia Econômica visando a implantação de Sistemas Fotovoltaicos Conectados à Rede Elétrica para todos os consumidores de Nova Veneza-GO e de Goiânia-GO, considerando dados de consumo disponibilizados pela concessionária local e também considerando dois diferentes cenários: implantação de sistemas fotovoltaicos com e sem incentivo do governo. Foi realizada ainda uma análise de Engenharia Econômica considerando uma adesão em Goiânia-GO de 1%, 5%, 10%, 20%, 30% e 100% das Unidades Consumidoras (UC). Resultados ambientais foram encontrados para a cidade de Nova Veneza-GO e Goiânia-GO, evidenciando uma redução expressiva na emissão de CO2 e uma grande economia de água.
246

Circuitos de acoplamento para transceptores PLC (Power Line Communications)

Costa, Luís Guilherme da Silva 24 February 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-20T17:56:56Z No. of bitstreams: 1 luisguilhermedasilvacosta.pdf: 5093972 bytes, checksum: 6380895e21a76520d3f4a10aad5a3371 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-24T16:50:02Z (GMT) No. of bitstreams: 1 luisguilhermedasilvacosta.pdf: 5093972 bytes, checksum: 6380895e21a76520d3f4a10aad5a3371 (MD5) / Made available in DSpace on 2017-04-24T16:50:02Z (GMT). No. of bitstreams: 1 luisguilhermedasilvacosta.pdf: 5093972 bytes, checksum: 6380895e21a76520d3f4a10aad5a3371 (MD5) Previous issue date: 2012-02-24 / Atualmente, há um grande interesse no desenvolvimento de transceptores PLC (power line communication) para a transmissão banda larga e banda estreita de dados visando, sobretudo, aplicações smart grids e de acesso banda larga. Para o avanço da tecnologia PLC, há grande demanda pela introdução de acopladores com características e desempenhos que viabilizem a conexão dos tranceptores PLC `as redes de energia elétrica, com o mínimo de distorção possível. Neste contexto, a presente contribuição versa sobre o estudo, a investigação, especificação, projeto e análise de acopladores capacitados para transceptores PLC SISO (single input single output) banda larga e banda estreita. Para tanto, são introduzidos acopladores PLC nas seguintes faixas de frequências: de 9 kHz `a 2 MHz, de 1,7 MHz `a 100 MHz e de 1,7 MHz `a 150 MHz. As análises dos projetos e dos protótipos dos acopladores, concebidos para operar nas referidas bandas, mostram as dificuldades encontradas para garantir que as especificações de projeto sejam atendidas quando os componentes passivos são comerciais e a faixa de frequência de operação do acoplador aumenta. Além disso, as análises confirmam a necessidade de consideração de técnicas de prototipação de placas de circuitos impresso para sinais de frequência elevada. Finalmente, os resultados de medição mostram que os acopladores para baixa frequência discutidos podem ser utilizados em sistemas de medição de canais PLC. / Currently, there is a great interest to develop power line communications (PLC) transceivers for broadband and narrowband data communications for smart grids and network access. However, for advancing PLC technologies, there is a great demand for introduction of couplers for connecting the PLC tranceivers to the electric energy circuits with minimum distortion. This contribution addresses the study, investigation, specification, design, and analysis of capacitive couplers for single input single output (SISO), broadband and narrowband PLC transceivers. Capacity and SISO PLC couplers covering the following frequencies bandwidth are addressed: from 9 kHz up to 2 MHz, from 1,7 MHz up to 100 MHz and from 1,7 MHz up to 150 MHz. The analysis performance of the designed and prototyped PLC couplers for operating in the aforementioned frequencies bandwidths, shows the inherent difficulties to guarantee that the design specifications are fulfilled when passive components are commercial ones and the frequency bandwidth increase. Additionally, the analysis confirms the need for taking into account advancing prototyping techniques for dealing with high-frequency signals. Finally, the measurements show that the discussed narrowband PLC couplers can be used in a PLC channel system.
247

Codage de canal et codage réseau pour les CPL-BE dans le contexte des réseaux Smart Grid / Channel coding and network coding for the CPL-BE in the context of networks Smart Grid

Kabore, Wendyida Abraham 09 March 2016 (has links)
Ce manuscrit traite de la fiabilisation des CPL-BE dans le contexte smart grid avec l’application des techniques de codage correcteur d’erreurs et d’effacements. Après une introduction sur le concept de smart grid, le canal CPL-BE est caractérisé précisément et les modèles qui le décrivent sont présentés. Les performances des codes à métrique rang, simples ou concaténés avec des codes convolutifs, particulièrement intéressants pour combattre le bruit criss-cross sur les réseaux CPL-BE sont simulées et comparées aux performances des codes Reed-Solomon déjà présents dans plusieurs standards. Les codes fontaines qui s’adaptent à n’importe quelles statistiques d’effacements sur le canal CPL sont utilisés et les performances de schémas coopératifs basés sur ces codes fontaines sur des réseaux linéaires multi-sauts sont étudiés. Enfin des algorithmes permettant de combiner le codage réseau et le codage fontaine pour la topologie particulière des réseaux CPL pour les smart grid sont proposés et évalués. / This PhD dissertation deals with the mitigation of the impact of the Narrowband PowerLine communication (NB-PLC) channel impairments e.g., periodic impulsive noise and narrowband noise, by applying the error/erasure correction coding techniques. After an introduction to the concept of smart grid, the NB-PLC channels are characterized precisely and models that describe these channels are presented. The performance of rank metric codes, simple or concatenated with convolutional codes, that are particularly interesting to combat criss-cross errors on the NB-PLC networks are simulated and compared with Reed- Solomon (already present in several NB-PLC standards) codes performance. Fountain codes that can adapt to any channel erasures statistics are used for the NB-PLC networks and the performance of cooperative schemes based on these fountain codes on linear multi-hop networks are studied. Finally, algorithms to combine the network coding and fountain codes for the particular topology of PLC networks for the smart grid are proposed and evaluated.
248

A tarifa horária para os consumidores residenciais sob o foco das redes elétricas inteligentes - REI / The hourly tariff to the residential consumers on the smart grid focus

Figueiró, Iuri Castro 24 July 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This Master s dissertation presents the development of a methodology to evaluate and estimate the behavior of the residential consumer facing the application of the white hourly tariff. In the context of the Smart Grids, this rate is applied aiming to encourage the consumers to shift their consumption to times of lower loading of system, looking for a better utilization of the infrastructure of the electric system. Considering this, the proposed methodology considers the analysis about the habits of use of electric shower, which is the household equipment that presents the greatest contribution on the final consumption and on the peak of the load curve of residential consumers. In this way the analysis considers data from the Brazilian Center of Information in Energy Efficiency - PROCEL INFO, which includes information about habits of use of household. This database, combined with the application of the Monte Carlo method, provide an overview of the possible effects of the application of the hourly rate to the consumers and to the electrical system, as well as, a guideline of actions that can be taken for a better adaptation of the consumers, considering this new trend. / Esta dissertação apresenta o desenvolvimento de uma metodologia para avaliar e estimar o comportamento do consumidor residencial frente a aplicação da tarifa horária branca. No contexto das Redes Elétricas Inteligentes, esta tarifa visa incentivar os consumidores a deslocarem o seu consumo para horários de menor carregamento do sistema e, consequentemente, buscar um melhor aproveitamento da infraestrutura do sistema elétrico. Neste sentido, a metodologia proposta considera a análise sobre os hábitos de utilização do chuveiro elétrico, carga com maior representatividade no consumo final e na ponta da curva de carga dos consumidores residenciais. Desta forma, são utilizados dados do Centro Brasileiro de Informação de Eficiência Energética PROCEL INFO, que reúne uma base de informações sobre os hábitos de utilização de equipamentos oriunda de pesquisas realizadas no mercado residencial brasileiro no ano de 2005. Esta base de dados, aliada a aplicação do Método de Monte Carlo, fornece uma visão dos possíveis efeitos da aplicação da tarifa horária para o consumidor e para o sistema elétrico, assim como, nortear ações que possam ser tomadas em função de uma melhor adaptação do consumidor frente a esta nova tendência.
249

Řízení velikosti napětí v NN síti pomocí distribučních a linkových transformátorů na základě distribuovaného měření / Voltage profile regulation in LV distribution systems by means of OLTC equipped distribution transformer and series transformers based on distributed monitoring data

Hála, Tomáš January 2018 (has links)
This diploma thesis discusses two major topics. The first one is the control size of the voltage in LV networks in regard to the increase in distributed generation concered to renewable energy sources. The study contains a review focused on the current state of low voltagegrid followed by a proposal for the solution of the oncoming state. The solution is identified as a deploying OLTC distribution transformer. In the case of more complex topology is deployed a series voltage transformer. Both methods are part of the Smart Grid. The thesis also analyzes the issue of the data measurement and data transmission. The second part of the thesis consists of the description of selected control strategies and their simulations. The design of individual system elements in the PSCAD is described. From these elements, a test network was constructed and tested the individual simulation scenarios.
250

Analyses probabilistes pour l'étude des réseaux électriques de distribution / Probabilistic load flow computation for unbalanced distribution grids with distributed generation

Diop, Fallilou 25 June 2018 (has links)
Les mutations observées sur le système électrique (production décentralisée, véhicules électriques, stockage, micro réseau...) font émerger des problématiques d'ordres économiques et techniques dans la gestion de ce dernier. Parmi eux, l'impact sur les niveaux de tension et de courant de neutre des réseaux de distribution. Le but de cette thèse est d'étudier des modèles probabilistes pour estimer ces impacts. L'incertitude sur la puissance PV produite et sur l'utilisation des VEs implique la nécessité de développer des modèles probabilistes de consommation et de production d'électricité. Deux modèles différents de production et de consommation ont été étudiés : L'un basé sur l'approximation de données historiques par une densité de probabilité, l'autre reposant sur la répartition des données en groupes définis par un profil type et une probabilité d'occurrence. Des techniques de load flow probabilistes ont été étudiées dans cette thèse pour prendre en compte l'effet intermittente de la production PV et l'incertitude sur la consommation. Une technique basée sur la méthode de simulation Monte Carlo, une deuxième basée sur l'approximation PEM et une dernière basée sur l'utilisation du clustering appelée méthode pseudo Monte Carlo. Après avoir comparé la pertinence des méthodes sur deux réseaux test, la méthode pseudo Monte Carlo est appliquée, pour son gain en temps de simulation et son adaptabilité, dans un cas d'application qui porte sur l'estimation de la probabilité de dépassement des limites du courant de neutre en fonction du déséquilibre de production PV installée. / The current changes on the electrical system bring out economic and technical issues in the management of the latter. Among these issues, the impact of distributed generation and VEs on the technical constraints of the distribution network. The aim of this thesis is to study probabilistic models to estimate the impacts of photovoltaic production and electrical vehicles on medium and low voltage distribution networks. Two different probabilistic models of production and consumption were studied : one based on the fitting of historical data by one probability density function, the other one based on the data clustered in groups defined by a standard profile and a probability of occurrence. Three probabilistic load flow technics have been studied in this thesis. The first is based on the Monte Carlo simulation method, the second is based on the PEM approximation method and the last, based on the use of clustering, is called pseudo Monte Carlo method.

Page generated in 0.098 seconds