• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 75
  • 42
  • 18
  • 8
  • 6
  • 4
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 192
  • 59
  • 48
  • 41
  • 34
  • 30
  • 24
  • 23
  • 21
  • 21
  • 20
  • 20
  • 19
  • 19
  • 19
  • 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.
141

Otimização do posicionamento de concentradores GPRS em redes elétricas inteligentes utilizando programação linear e teoria de filas / Positioning optmization of GPRS concentrators in smart grids using linear programming and queuing theory

Souza, Gustavo Batista de Castro 17 July 2014 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-01-13T10:55:38Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Gustavo Batista de Castro Souza - 2014.pdf: 11760996 bytes, checksum: 8245af285d79ff9e8079bafddb72e690 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-01-13T10:56:54Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Gustavo Batista de Castro Souza - 2014.pdf: 11760996 bytes, checksum: 8245af285d79ff9e8079bafddb72e690 (MD5) / Made available in DSpace on 2015-01-13T10:56:54Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Gustavo Batista de Castro Souza - 2014.pdf: 11760996 bytes, checksum: 8245af285d79ff9e8079bafddb72e690 (MD5) Previous issue date: 2014-07-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Smart Grids systems have become widespread around the world. The RF mesh communication systems have contributed to make power systems smarter and reliable with implementation of Distributed Automation and Demand Response technologies. This work presents a methodology for positioning of GPRS concentrators in a energy meter ZigBee mesh network in order to attain the average network delay, thus aiming to improve the performance of the communication service. The proposed algorithm determines the amount and placement of concentrators using Integer Linear Programming and a Queuing Model for the Mesh Network. The solutions given by the proposed algorithm are validated by verifying the network performance through computer simulations based on real network scenarios. / Smart Grids tem se difundido em todo o mundo. Sistemas de comunicação RF Mesh (em malha) tem contribuído para deixar sistemas de potência mais inteligentes e confiáveis com a implantação de tecnolgias de Automação da Distribuição e Resposta à Demanda. Este trabalho apresenta um metodologia de posicionamento de concentradores GPRS em uma rede ZigBee mesh de medidores de energia elétrica com o objetivo de limitar o delay médio da rede e assim otimizar o desempenho do serviço de comunicação. O algoritmo proposto determina a quantidade e a localização de concentradores utilizando Programação Linear Inteira e um Modelo de Filas para Redes Mesh. As soluções obtidas pelo algoritmo proposto são validadas verificando o desempenho da rede através de simulações computacionais baseadas em cenários reais de redes.
142

Micro-redes elétricas: estado da arte e contribuição para o dimensionamento, aplicação e comercialização da energia produzida. / Microgrid systems: a study on the state-of-the-art and contribution for the dimensioning, application and trading of the power produced.

Tesoro Elena Del Carpio Huayllas 16 June 2015 (has links)
As conseqüências e repercussões do recente blecaute de grande escala ocorrido no Brasil em 2009, que afetou as regiões Sudeste, Sul, Centro-Oeste e Nordeste além do Paraguai todo; assim como aqueles que afetaram a região do Norte e Nordeste dos Estados Unidos (2003) e toda Itália, também em 2003, mostraram mais uma vez que na atualidade a sociedade tem uma dependência quase total da energia elétrica. Em todos os casos, a falta de energia elétrica atingiu de forma significativa vários setores da economia, ao passo que sistemas de transporte elétrico, indústrias e hospitais sem sistemas de geração emergencial, instituições acadêmicas, iluminação pública e residencial e, inclusive, sistemas de comunicação, ficaram praticamente inoperantes. Após esses eventos, houve uma busca por algumas alternativas que ofereçam maior confiabilidade no fornecimento de energia elétrica ou, pelo menos, alternativas que ajudem a minimizar o seu impacto. O estabelecimento de sistemas baseados em micro-redes elétricas mostrou-se como uma alternativa que poderia ser utilizada para tal finalidade, de tal forma que não apenas cargas críticas, mas também boa parte das atividades mencionadas poderia continuar operando durante períodos de contingência. Por outro lado, o conceito das micro-redes elétricas tem ganho recentemente maior atenção em virtude da crescente penetração de fontes de geração distribuída e dos incentivos providos pelos governos para promover a geração de energia através de fontes renováveis como por exemplo a energia eólica, solar, biomassa, hidrelétrica, e outras. Nos mais diversos países do mundo, atualmente, populações assentadas em regiões remotas utilizam esquemas baseados em micro-redes elétricas para o suprimento de energia elétrica. Assim, neste trabalho serão apresentados os resultados referentes ao estudo da tecnologia das micro-redes elétricas, especificamente o seu desempenho diante de condições operativas como o modo de operação ilhado e o modo conectado com a rede elétrica. Particularmente, a transição para o modo de operação ilhado demandou um estudo, através das simulações, mais dedicado. No que se refere à negociação da energia entre a micro-rede e a rede principal, quando da disponibilidade de energia excedente nos períodos de carga reduzida na micro-rede, será apresentada uma análise crítica dos possíveis métodos de tarifação, os quais até agora são apenas utilizados na forma de incentivos governamentais. Será também apresentada uma análise referente à viabilidade econômica de micro-redes, já que para que estas tenham atratividade econômica, os custos de aquisição de equipamentos e operação devem também ser competitivos. / After the occurrence of some major blackouts like the one that affected the Northern and Northeastern part of the United States in 2003, the one that affected the Southeast, Midwest and Northeastern part of Brazil including Paraguay, in 2009; and the blackout that affected the whole Italy in 2003, to mention a few a few of them, there was a rush for seeking some alternatives to deal with such events or at least find out feasible solutions that can contribute to diminish their impact. The lack of electric power, for whatever reason it was, unveiled one common fact, our modern society is so dependent on electricity that during the blackouts areas like the electrical transport system, financing activity, academic institutions, industries, health centers with no emergency or standby generation, public and residential lighting and even some communication systems failed to operate. The establishment of microgrid systems proved to be an alternative that could be used for this purpose; thus, not only critical loads, but also some of the activities mentioned earlier on could continue their operation during such emergency periods. In addition, the concept of micro-grid systems has recently gained particular attention due to the increasing penetration of distributed generation and also due to the incentives provided by the governments to promote the generation of electricity from renewable sources such as wind power, solar, biomass, small hydroelectric schemes, etc. At present, countless settlements located in remote areas worldwide use microgrid systems to generate and distribute electricity. In this work, the results related to the microgrid technology, specifically its performance towards system conditions such as the islanding mode and grid connected mode of operation will be presented. Particularly, the transition to the islanded mode of operation demanded a more dedicated study during the simulations performed. As for the energy trading between the microgrid and the utility, which can occur when the microgrid generators are lightly loaded, it will be presented a critical analysis about the possible tariff methods to be applied. Such tariffs are so far only applied in the form of government subsidies to promote the use of renewable energy sources. Additionally, an analysis of a microgrid economic feasibility to show how competitive or complimentary this technology is with the utility will be presented herein.
143

Compressão de dados de demanda elétrica em Smart Metering / Data compression electricity demand in Smart Metering

Flores Rodriguez, Andrea Carolina, 1987- 08 August 2014 (has links)
Orientador: Gustavo Fraidenraich / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-26T03:16:11Z (GMT). No. of bitstreams: 1 FloresRodriguez_AndreaCarolina_M.pdf: 1415054 bytes, checksum: 6b986968e8d7ec4e6459e4cea044d379 (MD5) Previous issue date: 2014 / Resumo: A compressão dos dados de consumo residencial de energia elétrica registrados torna-se extremadamente necessária em Smart Metering, a fim de resolver o problema de grandes volumes de dados gerados pelos medidores. A principal contribuição desta tese é a proposta de um esquema de representação teórica da informação registrada na forma mais compacta, sugerindo uma forma de atingir o limite fundamental de compressão estabelecido pela entropia da fonte sobre qualquer técnica de compressão disponibilizada no medidor. A proposta consiste na transformação de codificação dos dados, baseado no processamento por segmentação: no tempo em taxas de registros de 1/900 Hz a 1 Hz, e nos valores de consumo residencial de energia elétrica. Este último subdividido em uma compressão por amplitude mudando sua granularidade e compressão dos dados digitais para representar o consumo com o menor número de bits possíveis usando: PCM-Huffman, DPCM-Huffman e codificação de entropia supondo diferentes ordens de distribuição da fonte. O esquema é aplicado sobre dados modelados por cadeias de Markov não homogêneas para as atividades dos membros da casa que influenciam no consumo elétrico e dados reais disponibilizados publicamente. A avaliação do esquema é feita analisando o compromisso da compressão entre as altas taxas de registro, distorção resultante da digitalização dos dados, e exploração da correlação entre amostras consecutivas. Vários exemplos numéricos são apresentados ilustrando a eficiência dos limites de compressão. Os resultados revelam que os melhores esquemas de compressão de dados são encontrados explorando a correlação entre as amostras / Abstract: Data compression of recorded residential electricity consumption becomes extremely necessary on Smart Metering, in order to solve the problem of large volumes of data generated by meters. The main contribution of this thesis is to propose a scheme of theoretical representation of recorded information in the most compact form, which suggests a way to reach the fundamental limit of compression set by the entropy of the source, of any compression technique available in the meter. The proposal consists in the transformation of data encoding, based on the processing by segmentation: in time by registration rate from 1/900 Hz to 1 Hz, and in the values of residential electricity consumption. The latter is subdivided into compression: by amplitude changing their regularity, and digital data compression to represent consumption as few bits as possible. It is using PCM-Huffman, DPCM-Huffman and entropy encoding by assuming different orders of the source. The scheme is applied to modeled data by inhomogeneous Markov chains to create the activities of household members that influence electricity consumption, and real data publicly available. The assessment scheme is made by analyzing the trade off of compression between high registration rates, the distortion resulting from the digitization of data, and analyzing the correlation of consecutive samples. Several examples are presented to illustrate the efficiency of the compression limits. The analysis reveals that better data compression schemes can be found by exploring the correlation among the samples / Mestrado / Telecomunicações e Telemática / Mestra em Engenharia Elétrica
144

For Improved Energy Economy – How Can Extended Smart Metering Be Displayed? / For Improved Energy Economy – How Can Extended Smart Metering Be Displayed?

Ahmed, Nisar, Yousaf, Shahid January 2011 (has links)
Context: A District Heating System (DHS) uses a central heating plant to produce and distribute hot water in a community. Such a plant is connected with consumers’ premises to provide them with hot water and space heating facilities. Variations in the consumption of heat energy depend upon different factors like difference in energy prices, living standards, environmental effects and economical conditions etc. These factors can manage intelligently by advanced tools of Information and Communication Technology (ICT) such as smart metering. That is a new and emerging technology; used normally for metering of District Heating (DH), district cooling, electricity and gas. Traditional meters measures overall consumption of energy, in contrast smart meters have the ability to frequently record and transmit energy consumption statistics to both energy providers and consumers by using their communication networks and network management systems. Objectives: First objective of conducted study was providing energy consumption/saving suggestions on smart metering display for accepted consumer behavior, proposed by the energy providers. Our second objective was analysis of financial benefits for the energy provides, which could be expected through better consumer behavior. Third objective was analysis of energy consumption behavior of the residential consumes that how we can support it. Moreover, forth objective of the study was to use extracted suggestions of consumer behaviors to propose Extended Smart Metering Display for improving energy economy. Methods: In this study a background study was conducted to develop basic understanding about District Heat Energy (DHE), smart meters and their existing display, consumer behaviors and its effects on energy consumption. Moreover, interviews were conducted with representatives of smart heat meters’ manufacturer, energy providers and residential consumers. Interviews’ findings enabled us to propose an Extended Smart Metering Display, that satisfies recommendations received from all the interviewees and background study. Further in this study, a workshop was conducted for the evaluation of the proposed Extended Smart Metering Display which involved representatives of smart heat meters’ manufacture and residential energy consumers. DHE providers also contributed in this workshop through their comments in online conversation, for which an evaluation request was sent to member companies of Swedish District Heating Association. Results: Informants in this research have different levels of experiences. Through a systematic procedure we have obtained and analyzed findings from all the informants. To fulfill the energy demands during peak hours, the informants emphasized on providing efficient energy consumption behavior to be displayed on smart heat meters. According to the informants, efficient energy consumption behavior can be presented through energy consumption/saving suggestions on display of smart meters. These suggestions are related to daily life activities like taking bath and shower, cleaning, washing and heating usage. We analyzed that efficient energy consumption behavior recommended by the energy providers can provide financial improvements both for the energy providers and the residential consumers. On the basis of these findings, we proposed Extended Smart Metering Display to present information in simple and interactive way. Furthermore, the proposed Extended Smart Metering Display can also be helpful in measuring consumers’ energy consumption behavior effectively. Conclusions: After obtaining answers of the research questions, we concluded that extension of existing smart heat meters’ display can effectively help the energy providers and the residential consumers to utilize the resources efficiently. That is, it will not only reduce energy bills for the residential consumers, but it will also help the energy provider to save scarce energy and enable them to serve the consumers better in peak hours. After deployment of the proposed Extended Smart Metering Display the energy providers will able to support the consumers’ behavior in a reliable way and the consumers will find/follow the energy consumption/saving guidelines easily. / mcs294@yahoo.com, shahid_yousaf27@yahoo.com
145

Smart Metering for Smart Electricity Consumption

Vadda, Praveen, Seelam, Sreerama Murthy January 2013 (has links)
In recent years, the demand for electricity has increased in households with the use of different appliances. This raises a concern to many developed and developing nations with the demand in immediate increase of electricity. There is a need for consumers or people to track their daily power usage in houses. In Sweden, scarcity of energy resources is faced during the day. So, the responsibility of human to save and control these resources is also important. This research work focuses on a Smart Metering data for distributing the electricity smartly and efficiently to the consumers. The main drawback of previously used traditional meters is that they do not provide information to the consumers, which is accomplished with the help of Smart Meter. A Smart Meter helps consumer to know the information of consumption of electricity for appliances in their respective houses. The aim of this research work is to measure and analyze power consumption using Smart Meter data by conducting case study on various households. In addition of saving electricity, Smart Meter data illustrates the behaviour of consumers in using devices. As power consumption is increasing day by day there should be more focus on understanding consumption patterns i.e. measurement and analysis of consumption over time is required. In case of developing nations, the technology of employing smart electricity meters is still unaware to many common people and electricity utilities. So, there is a large necessity for saving energy by installing these meters. Lowering the energy expenditure by understanding the behavior of consumers and its correlation with electricity spot prices motivated to perform this research. The methodology followed to analyze the outcome of this study is exhibited with the help of a case analysis, ARIMA model using XLSTAT tool and a flattening technique. Based on price evaluation results provided in the research, hypothesis is attained to change the behavior of consumers when they have better control on their habits. This research contributes in measuring the Smart Meter power consumption data in various households and interpretation of the data for hourly measurement could cause consumers to switch consumption to off-peak periods. With the results provided in this research, users can change their behavior when they have better control on their habits. As a result, power consumption patterns of Smart electricity distribution are studied and analyzed, thereby leading to an innovative idea for saving the limited resource of electrical energy. / +91 9908265578
146

Improvements to longitudinal clean development mechanism sampling designs for lighting retrofit projects

Carstens, Herman January 2014 (has links)
An improved model for reducing the cost of long-term monitoring in Clean Development Mechanism (CDM) lighting retrofit projects is proposed. Cost-effective longitudinal sampling designs use the minimum number of meters required to report yearly savings at the 90% confidence and 10% relative precision level for duration of the project (up to 10 years) as stipulated by the CDM. Improvements to the existing model include a new non-linear Compact Fluorescent Lamp population decay model based on the results of the Polish Efficient Lighting Project, and a cumulative sampling function modified to weight samples exponentially by recency. An economic model altering the cost function to a nett present value calculation is also incorporated. The search space for such sampling models are investigated and found to be discontinuous and stepped, requiring a heuristic for optimisation; in this case the Genetic Algorithm was used. Assuming an exponential smoothing rate of 0.25, an inflation rate of 6.44%, and an interest rate of 10%, results show that sampling should be more evenly distributed over the study duration than is currently considered optimal, and that the proposed improvements in model accuracy increase expected project costs in nett present value terms by approximately 20%. A sensitivity analysis reveals that the expected project cost is most sensitive to the reporting precision level, coefficient of variance, and reporting / Dissertation (MEng)--University of Pretoria, 2014. / gm2014 / Electrical, Electronic and Computer Engineering / Unrestricted
147

Smart Grid security : protecting users' privacy in smart grid applications

Mustafa, Mustafa Asan January 2015 (has links)
Smart Grid (SG) is an electrical grid enhanced with information and communication technology capabilities, so it can support two-way electricity and communication flows among various entities in the grid. The aim of SG is to make the electricity industry operate more efficiently and to provide electricity in a more secure, reliable and sustainable manner. Automated Meter Reading (AMR) and Smart Electric Vehicle (SEV) charging are two SG applications tipped to play a major role in achieving this aim. The AMR application allows different SG entities to collect users’ fine-grained metering data measured by users’ Smart Meters (SMs). The SEV charging application allows EVs’ charging parameters to be changed depending on the grid’s state in return for incentives for the EV owners. However, both applications impose risks on users’ privacy. Entities having access to users’ fine-grained metering data may use such data to infer individual users’ personal habits. In addition, users’ private information such as users’/EVs’ identities and charging locations could be exposed when EVs are charged. Entities may use such information to learn users’ whereabouts, thus breach their privacy. This thesis proposes secure and user privacy-preserving protocols to support AMR and SEV charging in an efficient, scalable and cost-effective manner. First, it investigates both applications. For AMR, (1) it specifies an extensive set of functional requirements taking into account the way liberalised electricity markets work and the interests of all SG entities, (2) it performs a comprehensive threat analysis, based on which, (3) it specifies security and privacy requirements, and (4) it proposes to divide users’ data into two types: operational data (used for grid management) and accountable data (used for billing). For SEV charging, (1) it specifies two modes of charging: price-driven mode and price-control-driven mode, and (2) it analyses two use-cases: price-driven roaming SEV charging at home location and price-control-driven roaming SEV charging at home location, by performing threat analysis and specifying sets of functional, security and privacy requirements for each of the two cases. Second, it proposes a novel Decentralized, Efficient, Privacy-preserving and Selective Aggregation (DEP2SA) protocol to allow SG entities to collect users’ fine-grained operational metering data while preserving users’ privacy. DEP2SA uses the homomorphic Paillier cryptosystem to ensure the confidentiality of the metering data during their transit and data aggregation process. To preserve users’ privacy with minimum performance penalty, users’ metering data are classified and aggregated accordingly by their respective local gateways based on the users’ locations and their contracted suppliers. In this way, authorised SG entities can only receive the aggregated data of users they have contracts with. DEP2SA has been analysed in terms of security, computational and communication overheads, and the results show that it is more secure, efficient and scalable as compared with related work. Third, it proposes a novel suite of five protocols to allow (1) suppliers to collect users accountable metering data, and (2) users (i) to access, manage and control their own metering data and (ii) to switch between electricity tariffs and suppliers, in an efficient and scalable manner. The main ideas are: (i) each SM to have a register, named accounting register, dedicated only for storing the user’s accountable data, (ii) this register is updated by design at a low frequency, (iii) the user’s supplier has unlimited access to this register, and (iv) the user cancustomise how often this register is updated with new data. The suite has been analysed in terms of security, computational and communication overheads. Fourth, it proposes a novel protocol, known as Roaming Electric Vehicle Charging and Billing, an Anonymous Multi-User (REVCBAMU) protocol, to support the priced-driven roaming SEV charging at home location. During a charging session, a roaming EV user uses a pseudonym of the EV (known only to the user’s contracted supplier) which is anonymously signed by the user’s private key. This protocol protects the user’s identity privacy from other suppliers as well as the user’s privacy of location from its own supplier. Further, it allows the user’s contracted supplier to authenticate the EV and the user. Using two-factor authentication approach a multi-user EV charging is supported and different legitimate EV users (e.g., family members) can be held accountable for their charging sessions. With each charging session, the EV uses a different pseudonym which prevents adversaries from linking the different charging sessions of the same EV. On an application level, REVCBAMU supports fair user billing, i.e., each user pays only for his/her own energy consumption, and an open EV marketplace in which EV users can safely choose among different remote host suppliers. The protocol has been analysed in terms of security and computational overheads.
148

The design of a software architectural framework for tunnelling metering protocols over TCP/IP and low bandwidth packet switched networks with support for proprietary addressing

Von Gordon, Albert Fredrich Johannes 25 October 2007 (has links)
This document discusses the concept of drivers implemented within the context of the REMPLI (Real-Time Energy Management over Power line and Internet, see section 1.8.) network. The process image approach and the tunnelling approach are presented and reasoning is given why the tunnelling approach is preferred. Each of the drivers implemented is associated with a specific metering protocol. This document further discusses the general architecture of such a driver structure. The generic software architecture serves as a framework for integrating serial communication based metering protocols over packet-orientated remote networks and meters, by tunnelling the protocol data units to the remote meters. Principally each Protocol Driver consists of three parts, one part situated at the Application Server, one at the Access Point and one at the Node. This document then gives a description of the general driver structure within the REMPLI network and briefly explains the functions of all the modules contained within the driver structure. An example is used to show how these modules, which make up the software architecture of the Protocol Driver, are used to send an application generated request from the Application Server to the Metering Equipment and sending the response back from the remote Metering Equipment to the Application Server. This dissertation further discusses the need for address translation within the REMPLI network and the need to restrict access to meters by using these addresses and an access control list. This document also discusses the need for a “Keep-alive” signalling scheme, if supported by the underlying protocol and gives a general concept as to how it should be implemented. The role of an Optimization Module is also discussed for low bandwidth networks by means of an M-Bus example. Finally the M-Bus protocol driver implementation is discussed. The results achieved are presented, showing that the driver architecture can successfully be used to tunnel the M-Bus protocol to remote meters, provided the underlying network conforms to the quality of service requirements determined by the implemented metering protocol. The work proposed in this document started off as part of the REMPLI project by the REMPLI team but was completed independently. / Dissertation (MEng (Computer Engineering))--University of Pretoria, 2008. / Electrical, Electronic and Computer Engineering / unrestricted
149

Implementace technologie smart meteringu do provozu malého obecního vodovodu / Implementation of smart water measurement technology into small municipal waterworks environment

Klučka, Tomáš January 2019 (has links)
The diploma thesis describes the actual situation of smart water metering, an overview of water meters suitable for remote data reading and individual components for application of remote data transmission including transmission itself. The thesis also contains the characteristics of available wireless data communication technologies and detailed solutions according to two companies specializing in remote transmission of water meter data. Subsequently, the pilot projects of large water company are presented, including practical findings. The practical part deals with the implementation of smart water metering in three specific municipalities, including a description of the area of interest, water supply system specification and possible limitations, the recommended technology, the requirements for putting in into operation and the pricing of technology and services according to two specialized companies. Finally, the possibilities of other using of smart water meter technology are discussed.
150

Návrh statistické přejímky / Proposal statistical acceprance

Macho, Vítězslav January 2010 (has links)
Work suggests detailed progress statistical acceprance products in serial story production inclusive take - over plan and operational characteristics.

Page generated in 0.1172 seconds