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  • 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.
11

Ferramenta de apoio à decisão para priorização de obras de manutenção em redes de distribuição de energia elétrica

Fernandes, Leandro January 2014 (has links)
O presente trabalho apresenta, primeiramente, o desenvolvimento e aplicação de uma Ferramenta de Apoio à Decisão (FAD), seguindo os conceitos de Sistemas de Informação (SI), para facilitar o acesso e visualização de informações técnicas estratégicas, e que possa compor um Sistema de Apoio à Decisão (SAD) que englobe o portfólio de informações necessárias para o planejamento da priorização de obras de investimento e expansão das redes de distribuição de energia. A FAD proposta realiza o tratamento de um grupo de dados relativos a incidência de interrupções de energia da rede de distribuição de uma concessionária do setor elétrico, de forma a disponibilizar as informações depuradas para auxílio na tomada assertiva de decisão para aplicação de recursos para execução de ações de manutenção em rede de distribuição. Em seguida, exibe a inclusão de uma função de análise, no aplicativo desenvolvido como Ferramenta de Apoio à Decisão (FAD), baseada na priorização multicriterial AHP (Analytic Hierarchy Process). A aplicação do método AHP indica as estações avançadas da concessionária que possuem prioridade para a aplicação de recursos que visam à execução de ações de manutenção em rede de distribuição para a melhoria nos indicadores de continuidades do fornecimento de energia. / This paper first introduces the development and application of a Decision Support Tool (FAD), following the concepts of Information Systems (IS), to facilitate the availability and visualization of strategic techniques information, and can compose a Decision Support System (DSS) that encompasses the entire portfolio of information needed for planning the prioritization of investment works and expansion of power distribution networks. The proposed FAD performs the treatment of a group of data on the incidence of power outages in the distribution of the electric utility industry network in order to provide information to aid in purified assertive decision making for application of resources for execution maintenance actions in the distribution network. Then displays the inclusion of an analysis function, the application developed as a Tool for Decision Support (FAD), multicriteria prioritization based on AHP (Analytic Hierarchy Process). The application of AHP method indicates the advanced utility stations that have priority for use of funds aimed at the implementation of maintenance actions in the distribution network to improve the indicators of continuity of power supply.
12

Ferramenta de apoio à decisão para priorização de obras de manutenção em redes de distribuição de energia elétrica

Fernandes, Leandro January 2014 (has links)
O presente trabalho apresenta, primeiramente, o desenvolvimento e aplicação de uma Ferramenta de Apoio à Decisão (FAD), seguindo os conceitos de Sistemas de Informação (SI), para facilitar o acesso e visualização de informações técnicas estratégicas, e que possa compor um Sistema de Apoio à Decisão (SAD) que englobe o portfólio de informações necessárias para o planejamento da priorização de obras de investimento e expansão das redes de distribuição de energia. A FAD proposta realiza o tratamento de um grupo de dados relativos a incidência de interrupções de energia da rede de distribuição de uma concessionária do setor elétrico, de forma a disponibilizar as informações depuradas para auxílio na tomada assertiva de decisão para aplicação de recursos para execução de ações de manutenção em rede de distribuição. Em seguida, exibe a inclusão de uma função de análise, no aplicativo desenvolvido como Ferramenta de Apoio à Decisão (FAD), baseada na priorização multicriterial AHP (Analytic Hierarchy Process). A aplicação do método AHP indica as estações avançadas da concessionária que possuem prioridade para a aplicação de recursos que visam à execução de ações de manutenção em rede de distribuição para a melhoria nos indicadores de continuidades do fornecimento de energia. / This paper first introduces the development and application of a Decision Support Tool (FAD), following the concepts of Information Systems (IS), to facilitate the availability and visualization of strategic techniques information, and can compose a Decision Support System (DSS) that encompasses the entire portfolio of information needed for planning the prioritization of investment works and expansion of power distribution networks. The proposed FAD performs the treatment of a group of data on the incidence of power outages in the distribution of the electric utility industry network in order to provide information to aid in purified assertive decision making for application of resources for execution maintenance actions in the distribution network. Then displays the inclusion of an analysis function, the application developed as a Tool for Decision Support (FAD), multicriteria prioritization based on AHP (Analytic Hierarchy Process). The application of AHP method indicates the advanced utility stations that have priority for use of funds aimed at the implementation of maintenance actions in the distribution network to improve the indicators of continuity of power supply.
13

Ferramenta de apoio à decisão para priorização de obras de manutenção em redes de distribuição de energia elétrica

Fernandes, Leandro January 2014 (has links)
O presente trabalho apresenta, primeiramente, o desenvolvimento e aplicação de uma Ferramenta de Apoio à Decisão (FAD), seguindo os conceitos de Sistemas de Informação (SI), para facilitar o acesso e visualização de informações técnicas estratégicas, e que possa compor um Sistema de Apoio à Decisão (SAD) que englobe o portfólio de informações necessárias para o planejamento da priorização de obras de investimento e expansão das redes de distribuição de energia. A FAD proposta realiza o tratamento de um grupo de dados relativos a incidência de interrupções de energia da rede de distribuição de uma concessionária do setor elétrico, de forma a disponibilizar as informações depuradas para auxílio na tomada assertiva de decisão para aplicação de recursos para execução de ações de manutenção em rede de distribuição. Em seguida, exibe a inclusão de uma função de análise, no aplicativo desenvolvido como Ferramenta de Apoio à Decisão (FAD), baseada na priorização multicriterial AHP (Analytic Hierarchy Process). A aplicação do método AHP indica as estações avançadas da concessionária que possuem prioridade para a aplicação de recursos que visam à execução de ações de manutenção em rede de distribuição para a melhoria nos indicadores de continuidades do fornecimento de energia. / This paper first introduces the development and application of a Decision Support Tool (FAD), following the concepts of Information Systems (IS), to facilitate the availability and visualization of strategic techniques information, and can compose a Decision Support System (DSS) that encompasses the entire portfolio of information needed for planning the prioritization of investment works and expansion of power distribution networks. The proposed FAD performs the treatment of a group of data on the incidence of power outages in the distribution of the electric utility industry network in order to provide information to aid in purified assertive decision making for application of resources for execution maintenance actions in the distribution network. Then displays the inclusion of an analysis function, the application developed as a Tool for Decision Support (FAD), multicriteria prioritization based on AHP (Analytic Hierarchy Process). The application of AHP method indicates the advanced utility stations that have priority for use of funds aimed at the implementation of maintenance actions in the distribution network to improve the indicators of continuity of power supply.
14

Metodologias para analise do risco de ocorrencia de ilhamentos não intencionais de geradores sincronos distribuidos / Methodologies for evaluating the risk of occurrence of non intentional islanding of distributed synchronous generators

Salles Corrêa, Diogo 25 June 2008 (has links)
Orientadores: Walmir de Freitas Filho, Jose Carlos de Melo Vieira Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-11T06:20:40Z (GMT). No. of bitstreams: 1 SallesCorrea_Diogo_M.pdf: 1373306 bytes, checksum: a6a2357bf0c337089786c03c519bbd7d (MD5) Previous issue date: 2008 / Resumo: Geradores síncronos conectados em redes de distribuição de energia elétrica estão sujeitos a operarem de forma ilhada após contingências como, por exemplo, curtos-circuitos. Ilhamento ocorre quando uma parte da rede de distribuição opera eletricamente isolada da subestação da concessionária, mas continua a ser energizada por geradores distribuídos. Devido a um conjunto de implicações técnicas e de segurança, a prática atualmente utilizada pelas concessionárias e recomendada pelos principais guias técnicos é desconectar todos os geradores da rede isolada tão logo ocorra um ilhamento. Existem diversas técnicas de proteção desenvolvidas para detectar ilhamentos e a maioria delas possui limitações técnicas e são propensas a falharem em determinadas situações. Neste contexto, torna-se importante conhecer a probabilidade ou risco da proteção falhar na detecção de ilhamentos em sistemas de distribuição de energia elétrica com geradores distribuídos e, por conseguinte, decidir se o sistema de proteção utilizado é adequado ou não. A falha da detecção de uma situação de ilhamento é tecnicamente denominada ilhamento não intencional. Esta dissertação de mestrado apresenta uma série de metodologias desenvolvidas para analisar o risco da ocorrência de ilhamentos não intencionais devido à falha do sistema de proteção de geradores síncronos. O sistema de proteção antiilhamento considerado neste trabalho é composto por relés baseados em medidas de freqüência e/ou tensão visto que atualmente estes são considerados os dispositivos mais eficientes para realizar tal tarefa. Como os desempenhos desses relés estão fortemente relacionados aos desbalanços de potência ativa e reativa na rede ilhada, respectivamente, as metodologias desenvolvidas baseiam-se nas curvas de carga do sistema de distribuição, nos patamares de geração de potência ativa e reativa e no cálculo de um índice numérico que indica o risco de falha da proteção antiilhamento. Diversos métodos eficientes foram desenvolvidos para calcular diretamente este índice de risco sem a necessidade de executar numerosas simulações de transitórios eletromagnéticos. Ressalta-se que os principais fatores que afetam o desempenho do sistema de proteção antiilhamento podem ser prontamente determinados com a aplicação das metodologias desenvolvidas. Os resultados obtidos mostraram-se precisos quando comparados aos obtidos por meio de repetidas simulações do tipo de transitórios eletromagnéticos / Abstract: Distributed synchronous generators connected to distribution power systems are prone to operate islanded after contingencies such as short circuits. Islanding occurs when a portion of the distribution network operates electrically isolated from the utility grid substation, yet continues to be energized by local distributed generators connected to the isolated system. Due to a number of technical and safety concerns, the procedure currently adopted by utilities and recommended by the main technical guides is to disconnect all the generators immediately after an islanding event. There are several anti-islanding techniques and the majority of them present technical limitations so that they are likely to fail in certain situations. In this context, it becomes important to know the probability or the risk of the protection scheme to fail in the detection of islanding events in distribution power systems containing distributed generators and, ultimately, determine whether the protection scheme under study is adequate or not. The failure of islanding detection is technically denominated non intentional islanding. This work presents a number of methodologies developed to evaluate the risk of occurrence of non intentional islanding due to the failure of synchronous generators protection systems. The anti-islanding protection system considered in this work is composed of relays based on measures of frequency and/or voltage, since these are considered to be the most efficient methods to perform this task. As the performance of these relays is strongly dependent on the active and reactive power imbalances in the islanded system, respectively, the methodologies are based on the distribution network feeder load curves, the active and reactive power generation levels and on the calculation of numerical index to quantify the risk level of protection system failure. Efficient methods were developed to directly calculate these risk indexes without performing several electromagnetic transient simulations. Through these methods, the main factors impacting on the performance of the antiislanding protection schemes can be determined. The results obtained by the usage of the proposed methodologies presented a very good match with those obtained by electromagnetic transient simulations / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica
15

Application Of ANN Techniques For Identification Of Fault Location In Distribution Networks

Ashageetha, H 10 1900 (has links)
Electric power distribution network is an important part of electrical power systems for delivering electricity to consumers. Electric power utilities worldwide are increasingly adopting the computer aided monitoring, control and management of electric power distribution systems to provide better services to the electrical consumers. Therefore, research and development activities worldwide are being carried out to automate the electric power distribution system. The power distribution system consists of a three-phase source supplying power through single-, two-, or three-phase distribution lines, switches, and transformers to a set of buses with a given load demand. In addition, unlike transmission systems, single-, two-, and three-phase sections exist in the network and single-, two-, and three-phase loads exist in the distribution networks. Further, most distribution systems are overhead systems, which are susceptible to faults caused by a variety of situations such as adverse weather conditions, equipment failure, traffic accidents, etc. When a fault occurs on a distribution line, it is very important for the utility to identify the fault location as quickly as possible for improving the service reliability. Hence, one of the crucial blocks in the operation of distribution system is that of fault detection and it’s location. The achievement of this objective depends on the success of the distribution automation system. The distribution automation system should be implemented quickly and accurately in order to isolate those affected branches from the healthy parts and to take alternative measures to restore normal power supply. Fault location in the distribution system is a difficult task due to its high complexity and difficulty caused by unique characteristics of the distribution system. These unique characteristics are discussed in the present work. In recent years, some techniques have been discussed for the location of faults, particularly in radial distribution systems. These methods use various algorithmic approaches, where the fault location is iteratively calculated by updating the fault current. Heuristic and Expert System approaches for locating fault in distribution system are also proposed which uses more measurements. Measurements are assumed to be available at the sending end of the faulty line segment, which are not true in reality as the measurements are only available at the substation and at limited nodes of the distribution networks through the use of remote terminal units. The emerging techniques of Artificial Intelligence (AI) can be a solution to this problem. Among the various AI based techniques like Expert systems, Fuzzy Set and ANN systems, the ANN approach for fault location is found to be encouraging. In this thesis, an ANN approaches with limited measurements are used to locate fault in long distribution networks with laterals. Initially the distribution system modeling (using actual a-b-c phase representation) for three-, two-, and single-phase laterals, three-, two-, and single- phase loads are described. Also an efficient three-phase load flow and short circuit analysis with loads are described which is used to simulate all types of fault conditions on distribution systems. In this work, function approximation (FA) is the main technique used and the classification techniques take a major supportive role to the FA problem. Fault location in distribution systems is explained as a FA problem, which is difficult to solve due to the various practical constraints particular to distribution systems. Incorporating classification techniques reduce this FA problem to simpler ones. The function that is approximated is the relation between the three-phase voltage and current measurements at the substation and at selected number of buses (inputs), and the line impedance of the fault points from the substation (outputs). This function is approximated by feed forward neural network (FFNN). Similarly for solving the classification problems such as fault type classification and source short circuit level classification, Radial Basis Probabilistic Neural Network (RBPNN) has been employed. The work presented in this thesis is the combinational use of FFNN and RBPNN for estimating the fault location. Levenberg Marquardt learning method, which is robust and fast, is used for training FFNN. A typical unbalanced 11-node test system, an IEEE 34 nodes test system and a practical 69- bus long distribution systems with different configurations are considered for the study. The results show that the proposed approaches of fault location gives accurate results in terms of estimated fault location. Practical situations in distribution systems such as unbalanced loading, three-, two-, and single- phase laterals, limited measurements available, all types of faults, a wide range of varying source short circuit levels, varying loading conditions, long feeders with multiple laterals and different network configurations are considered for the study. The result shows the feasibility of applying the proposed method in practical distribution system fault diagnosis.
16

Caractérisation et modélisation de nouvelles capacités «Through Silicon Capacitors» à forte intégration pour la réduction de consommation et la montée en fréquence dans les architectures 3D de circuits intégrés / Characterization and modeling of new capacitors"Through Silicon Capacitors" highly integrated to reducing consumptionand to allow high frequency operating in 3D integrated circuit

Dieng, Khadim 23 November 2016 (has links)
La diminution de la longueur de grille des transistors a été le moteur essentiel de l’évolution des circuits intégrés microélectroniques ces dernières décennies. Toutefois, cette évolution des circuits microélectroniques a entrainé une densification des lignes d’interconnexion, donc la génération de fortes pertes, des ralentissements et de la diaphonie sur les signaux transmis, ainsi qu’une augmentation de l’impédance parasite des interconnexions. Cette dernière est néfaste pour l’intégrité de l’alimentation des composants actifs présents dans le circuit. Son augmentation multiplie le risque d’apparition d’erreurs numériques conduisant au dysfonctionnement d’un système. Il est donc nécessaire de réduire l’impédance sur le réseau d’alimentation des circuits intégrés. Pour ce faire, les condensateurs de découplage sont utilisés et placés hiérarchiquement à différents étages des circuits et dans leur intégralité (PCB, package, interposeur, puce).Ces travaux de doctorat s’inscrivent dans le cadre des développements récents des nouvelles solutions d’intégration 3D en microélectronique et ils portent sur l’étude de nouvelles architectures de capacités 3D, très intégrées et à fortes valeurs (>1 nF), élaborées en profondeur dans l’interposeur silicium. Ces composants, inspirés des architectures de via traversant le silicium (TSV, Through Silicon Via), sont nommées Through Silicon Capacitors (TSC). Ils constituent un élément clef pour l’amélioration des performances des alimentations des circuits intégrés car elles pourront réduire efficacement la consommation des circuits grâce à cette intégration directe de composants passifs dans l’interposeur silicium qui sert d’étage d’accueil des puces. Ces composants tridimensionnels permettent en effet d’atteindre de grandes densités de capacité de 35 nF/mm². Les enjeux sont stratégiques pour des applications embarquées et à haut débit et plus généralement dans un environnement économique et sociétal conscient de nos limites énergétiques. De plus ces condensateurs de découplage doivent fonctionner à des fréquences atteignant 2 GHz, voire 4 GHz, qui tendent à maximiser les effets parasites préjudiciables aux performances énergétiques des alimentations. Ceci est rendu possible par l’optimisation de leur intégration et l’utilisation de couches de cuivre avec, une bonne conductivité supérieure à 45 MS/m, comme électrodes.Les technologies d’élaboration des condensateurs TSC ont été développées au sein du CEA-LETI et de STMicroelectronics. Leur comportement électrique restait jusqu’alors mal connu et leurs performances difficiles à quantifier. Les études menées dans cette thèse consistaient à modéliser ces nouveaux composants en prenant en compte les paramètres matériaux et géométriques afin de connaitre les effets parasites. Les modèles électriques établis ont été confrontés à des caractérisations électriques effectuées sur une large bande de fréquence (du DC à 40 GHz). Ainsi ce travail a permis d’optimiser une architecture de capacité et leur intégration dans un réseau d’alimentation d’un circuit intégré 3D a pu montrer leur efficacité pour des opérations de découplage. / The decrease of transistor’s gate length was the key driver of the development of microelectronic integrated circuits in recent decades. However, this development of microelectronic circuits has led to a greater density of interconnection lines, generating high losses, slowdowns and crosstalk on the transmitted signals, and an increase of the parasitic impedance of interconnections lines. The latter is detrimental to the power integrity of the active components in the circuit. Its increase increases the risk of developing numerical errors leading to a system’s malfunction. It is therefore necessary to reduce the impedance of the power distribution network of integrated circuits. To do this, the decoupling capacitors are used and placed hierarchically on different floors of the circuits and in their entirety (PCB, package, interposer, chip).These doctoral works are in the context of recent developments in new 3D integration solutions in microelectronics and they carry on studying new 3D capacitors, highly integrated, presenting high capacitance values (> 1 nF), and developed by using the depth of silicon interposeur level. Inspired from the Through Silicon Vias (TSV), these newly developed 3D capacitors are named Through Silicon Capacitors (TSC). They are a key element for improving the performance of the power integrated circuits because they can efficiently reduce the consumption of circuits thanks to their direct integration in silicon interposer which is used to stack chips. These 3D components allow tor reach high capacitance density up to 35 nF/mm². The issues are strategic for high speed embedded applications and more generally in an economic and societal environment aware of our energy limits. Moreover these decoupling capacitors must operate at frequencies up to 2 GHz or 4 GHz, which tend to maximize the parasitic effects which affect the energy efficiency of power distribution networks. This is made possible by optimizing their integration and by the use of copper layers with a good conductivity higher than 45 MS / m conductivity as electrodes.The technologies used to fabricate the TSC are developed by CEA-LETI and STMicroelectronics. The electrical behavior of those TSC remained hitherto little known and their performances difficult to quantify. The studies conducted in this thesis were to model these new components by taking into account the material and geometrical parameters in order to know the parasitic effects. The established electrical models have faced electrical characterizations carried out over a wide frequency range (DC to 40 GHz). This work allow to optimize the TSC architecture and their integration in a power distribution network (Power Distribution Network - NDS) prove that they are good candidate for decoupling operations.
17

Discovering frequent and significant episodes. Application to sequences of events recorded in power distribution networks

Quiroga Quiroga, Oscar Arnulfo 18 December 2012 (has links)
This thesis proposes a formalism to analyse and automatically exploit sequences of events, which are related with faults occurred in power distribution networks and are recorded by power quality monitors at substations. This formalism allows to find dependencies or relationships among events, looking for meaningful patterns. Once those patterns are found, they can be used to better describe fault situations and their temporal evolution or can be also useful to predict future failures by recognising the events that match the early stages of a pattern. / En aquesta tesi es proposa un formalisme per analitzar conjunts de dades d'esdeveniments relacionats amb les fallades que es produeixen en les xarxes de distribució elèctrica, i explotar automàticament seqüències d'esdeveniments registrats pels monitors de qualitat d'ona instal•lats en substacions. Aquest formalisme permet cercar dependencies o relacions entre esdeveniments per trobar patrons significatius. Quan els patrons es troben, es poden utilitzar per descriure millor les situacions de fallada i la seva evolució. Els patrons també poden ser útils per a predir fallades futures mitjançant el reconeixement dels successos que coincideixin amb les primeres etapes d'un patró.

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