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Shimotakahara, Kevin. "Device to Device Communications for Smart Grid." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40656.
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This thesis identifies and addresses two barriers to the adoption of Long Term Evolution (LTE) Device-to-Device (D2D) communication enabled smart grid applications in out of core network coverage regions. The first barrier is the lack of accessible simulation software for engineers to develop and test the feasibility of their D2D LTE enabled smart grid application designs. The second barrier is the lack of a distributed resource allocation algorithm for LTE D2D communications that has been tailored to the needs of smart grid applications.
A solution was proposed to the first barrier in the form of a simulator constructed in
Matlab/Simulink used to simulate power systems and the underlying communication
system, i.e., D2D communication protocol stack of Long Term Evolution (LTE). The
simulator is built using Matlab's LTE System Toolbox, SimEvents, and Simscape Power Systems in addition to an in-house developed interface software to facilitate D2D communications in smart grid applications. To test the simulator, a simple fault location, isolation, and restoration (FLISR) application was implemented using the simulator to show that the LTE message timing is consistent with the relay signaling in the power system.
A solution was proposed to the second barrier in the form of a multi-agent Q-learning based resource allocation algorithm that allows Long Term Evolution (LTE) enabled
device-to-device (D2D) communication agents to generate orthogonal transmission schedules outside of network coverage. This algorithm reduces packet drop rates (PDR) in distributed D2D communication networks to meet the quality of service requirements of microgrid communications. The PDR and latency performance of the proposed algorithm was compared to the existing random self-allocation mechanism introduced under the Third Generation Partnership Project's LTE Release 12. The proposed algorithm outperformed the LTE algorithm for all tested scenarios, demonstrating 20-40% absolute reductions in PDR and 10-20 ms reductions in latency for all microgrid applications.
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Kanten, Bethany. "Power Monitoring Device for Off-Grid Solar." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:14398556.
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Off-grid solar power systems are being used in rural, developing regions of the world to provide electricity to communities that previously didn’t have access. These systems are unable to communicate data about power generation and consumption to the organizations that install them. This information can be critical for the organization to ensure they are providing quality electricity, maintain the health of the components in their system, and evaluate the impact they are having in the community. I designed and built a device to monitor power at both the generation and AC or DC consumption sites. Once daily it sends the data to a website via text message where is it displayed to the installer. The device also stores the data locally on a microSD card. The final device abides by the key specifications set by the prior art of low cost and low power consumption. The device also addresses key challenges of off-grid monitoring including data transmission via text message, battery monitoring, reliability/ durability, and versatility with load site monitoring.
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Bürgler, Josef Franz. "Discretization and grid adaptation in semiconductor device modeling /." [S.l.] : [s.n.], 1990. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=9146.
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Conti, Paolo. "Grid generation for three-dimensional semiconductor device simulation /." Zürich, 1991. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=9383.
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Minh, Hyunsik Eugene. "Communication options for protection and control device in Smart Grid applications." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82401.
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Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; in conjunction with the Leaders for Global Operations Program at MIT, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 74-75).
Increasing use of electricity, interest in renewable energy sources, and need for a more reliable power grid system are some of the many drivers for the concept of the Smart Grid technology. In order to achieve these goals, one of the critical elements is communication between systems or between the system and human beings. With the decreasing cost of various communication technologies, especially wireless devices and utilities, researchers are increasingly interested in implementing complex two-way communication infrastructures to enhance the quality of the grid. The protection and control relay at the distribution level is one of the key component in enhancing the efficiency, security and reliability of power grid. At present, it may be premature to apply wireless devices to power electronics and to distribution automation, especially for protection and control relays in the distribution level. While fiber technology is still very attractive for protection and control applications in general, wireless technology can bring improvements in user experience applications in the future. The ABB medium voltage group needs to overcome challenges that arise from conservative industry structure, increasing complexity and cost of the product, and needs for higher reliability and security. However, with collaborative efforts among different product groups, the medium voltage group will successfully develop next generation distribution feeder relay.
by Hyunsik Eugene Minh.
S.M.
M.B.A.
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Kalalas, Charalampos. "Cellular networks for smart grid communication." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/620760.
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The next-generation electric power system, known as smart grid, relies on a robust and reliable underlying communication infrastructure to improve the efficiency of electricity distribution. Cellular networks, e.g., LTE/LTE-A systems, appear as a promising technology to facilitate the smart grid evolution. Their inherent performance characteristics and well-established ecosystem could potentially unlock unprecedented use cases, enabling real-time and autonomous distribution grid operations. However, cellular technology was not originally intended for smart grid communication, associated with highly-reliable message exchange and massive device connectivity requirements. The fundamental differences between smart grid and human-type communication challenge the classical design of cellular networks and introduce important research questions that have not been sufficiently addressed so far. Motivated by these challenges, this doctoral thesis investigates novel radio access network (RAN) design principles and performance analysis for the seamless integration of smart grid traffic in future cellular networks.
Specifically, we focus on addressing the fundamental RAN problems of network scalability in massive smart grid deployments and radio resource management for smart grid and human-type traffic. The main objective of the thesis lies on the design, analysis and performance evaluation of RAN mechanisms that would render cellular networks the key enabler for emerging smart grid applications.
The first part of the thesis addresses the radio access limitations in LTE-based networks for reliable and scalable smart grid communication. We first identify the congestion problem in LTE random access that arises in large-scale smart grid deployments. To overcome this, a novel random access mechanism is proposed that can efficiently support real-time distribution automation services with negligible impact on the background traffic. Motivated by the stringent reliability requirements of various smart grid operations, we then develop an analytical model of the LTE random access procedure that allows us to assess the performance of event-based monitoring traffic under various load conditions and network configurations. We further extend our analysis to include the relation between the cell size and the availability of orthogonal random access resources and we identify an additional challenge for reliable smart grid connectivity. To this end, we devise an interference- and load-aware cell planning mechanism that enhances reliability in substation automation services. Finally, we couple the problem of state estimation in wide-area monitoring systems with the reliability challenges in information acquisition. Using our developed analytical framework, we quantify the impact of imperfect communication reliability in the state estimation accuracy and we provide useful insights for the design of reliability-aware state estimators.
The second part of the thesis builds on the previous one and focuses on the RAN problem of resource scheduling and sharing for smart grid and human-type traffic. We introduce a novel scheduler that achieves low latency for distribution automation traffic while resource allocation is performed in a way that keeps the degradation of cellular users at a minimum level. In addition, we investigate the benefits of Device-to-Device (D2D) transmission mode for event-based message exchange in substation automation scenarios. We design a joint mode selection and resource allocation mechanism which results in higher data rates with respect to the conventional transmission mode via the base station. An orthogonal resource partition scheme between cellular and D2D links is further proposed to prevent the underutilization of the scarce cellular spectrum.
The research findings of this thesis aim to deliver novel solutions to important RAN performance issues that arise when cellular networks support smart grid communication.Las redes celulares, p.e., los sistemas LTE/LTE-A, aparecen como una tecnología prometedora para facilitar la evolución de la próxima generación del sistema eléctrico de potencia, conocido como smart grid (SG). Sin embargo, la tecnología celular no fue pensada originalmente para las comunicaciones en la SG, asociadas con el intercambio fiable de mensajes y con requisitos de conectividad de un número masivo de dispositivos. Las diferencias fundamentales entre las comunicaciones en la SG y la comunicación de tipo humano desafían el diseño clásico de las redes celulares e introducen importantes cuestiones de investigación que hasta ahora no se han abordado suficientemente. Motivada por estos retos, esta tesis doctoral investiga los principios de diseño y analiza el rendimiento de una nueva red de acceso radio (RAN) que permita una integración perfecta del tráfico de la SG en las redes celulares futuras. Nos centramos en los problemas fundamentales de escalabilidad de la RAN en despliegues de SG masivos, y en la gestión de los recursos radio para la integración del tráfico de la SG con el tráfico de tipo humano. El objetivo principal de la tesis consiste en el diseño, el análisis y la evaluación del rendimiento de los mecanismos de las RAN que convertirán a las redes celulares en el elemento clave para las aplicaciones emergentes de las SGs. La primera parte de la tesis aborda las limitaciones del acceso radio en redes LTE para la comunicación fiable y escalable en SGs. En primer lugar, identificamos el problema de congestión en el acceso aleatorio de LTE que aparece en los despliegues de SGs a gran escala. Para superar este problema, se propone un nuevo mecanismo de acceso aleatorio que permite soportar de forma eficiente los servicios de automatización de la distribución eléctrica en tiempo real, con un impacto insignificante en el tráfico de fondo. Motivados por los estrictos requisitos de fiabilidad de las diversas operaciones en la SG, desarrollamos un modelo analítico del procedimiento de acceso aleatorio de LTE que nos permite evaluar el rendimiento del tráfico de monitorización de la red eléctrica basado en eventos bajo diversas condiciones de carga y configuraciones de red. Además, ampliamos nuestro análisis para incluir la relación entre el tamaño de celda y la disponibilidad de recursos de acceso aleatorio ortogonales, e identificamos un reto adicional para la conectividad fiable en la SG. Con este fin, diseñamos un mecanismo de planificación celular que tiene en cuenta las interferencias y la carga de la red, y que mejora la fiabilidad en los servicios de automatización de las subestaciones eléctricas. Finalmente, combinamos el problema de la estimación de estado en sistemas de monitorización de redes eléctricas de área amplia con los retos de fiabilidad en la adquisición de la información. Utilizando el modelo analítico desarrollado, cuantificamos el impacto de la baja fiabilidad en las comunicaciones sobre la precisión de la estimación de estado. La segunda parte de la tesis se centra en el problema de scheduling y compartición de recursos en la RAN para el tráfico de SG y el tráfico de tipo humano. Presentamos un nuevo scheduler que proporciona baja latencia para el tráfico de automatización de la distribución eléctrica, mientras que la asignación de recursos se realiza de un modo que mantiene la degradación de los usuarios celulares en un nivel mínimo. Además, investigamos los beneficios del modo de transmisión Device-to-Device (D2D) en el intercambio de mensajes basados en eventos en escenarios de automatización de subestaciones eléctricas. Diseñamos un mecanismo conjunto de asignación de recursos y selección de modo que da como resultado tasas de datos más elevadas con respecto al modo de transmisión convencional a través de la estación base. Finalmente, se propone un esquema de partición de recursos ortogonales entre enlaces celulares y D2
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Schmithüsen, Bernhard. "Grid adaptation for the stationary two-dimensional drift-diffusion model in semiconductor device simulation /." Zürich : [s.n.], 2002. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=14449.
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Xu, Chunchun. "High Accuracy Real-time GPS Synchronized Frequency Measurement Device for Wide-area Power Grid Monitoring." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27007.
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Frequency dynamics is one of the most important signals of a power system, and it is an indicator of imbalance between generation and load in the system. The Internet-based real-time GPS-synchronized wide-area Frequency Monitoring Network (FNET) was proposed to provide imperative frequency dynamics information for a variety of system-wide monitoring, analysis and control applications. The implementation of FNET has for the first time made the synchronized observation of the entire U.S. power network possible with very little cost.
The FNET is comprised of many Frequency Disturbance Recorders (FDR) geographically dispersed throughout the U.S. and an Information Management System (IMS), currently located at Virginia Tech. The FDR works as a sensor, which performs local measurements and transmits calculations of frequency, voltage magnitude and voltage angle to the remote servers via the Internet. Compared with its commercial counterpart Phasor Measurement Unit (PMU), FDR provides less expensive version for networked high-resolution real-time synchronized. The improved single phase algorithm in the FDRs made it possible to measure at 110V level which is much more challenging than PMUs due to the noise involved at this level.
This research work presents the challenges and issues of both software and hardware design for the novel measurement device FDR, which is one of the devices with the highest dynamic precision for power system frequency measurement. The DFT-based Phasor Angle Analysis algorithm has been improved to make sure the high-resolution measuring FDRs are installed at residential voltage outlets, instead of substation high-voltage inputs. An embedded 12-channel timing GPS receiver has been integrated to provide an accurate timing synchronization signal, UTC time stamp, and unit location. This research work also addresses the harmonics, voltage swing and other noise components' impacts on the measurement results, and the optimized design of filters and a coherent sampling scheme to reduce or eliminate those impacts. The verification test results show that the frequency measurement accuracy of the FDR is within +/-0.0005Hz, and the time synchronization error is within +/-500ns with suitable GPS antenna installation. The preliminary research results show the measurement accuracy and real-time performance of the FDR are satisfactory for a variety of FNET applications, such as disturbance identification and event location triangulation.Ph. D.
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Milette, Greg P. "Analogical matching using device-centric and environment-centric representations of function." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-050406-145255/.
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Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: Analogy, Design, Functional Modeling, Functional Reasoning, Knowledge Representation, Repertory Grid, SME, Structure Mapping Engine, AI in design. Includes bibliographical references (p.106).
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Orebowale, Patience B. "Investigating the stability of geosynthetic landfill capping systems." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/7786.
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The use of geosynthetics in landfill construction introduces potential planes of weakness. As a result, there is a requirement to assess the stability along the soil/geosynthetic and geosynthetic/geosynthetic interfaces. Stability is governed by the shear strength along the weakest interface in the system. Repeatability interface shear strength testing of a geomembrane/geotextile interface at low normal stresses suitable for capping systems showed considerable variability of measured geosynthetic interface shear strengths, suggesting that minor factors can have a significant influence on the measured shear strength. This study demonstrates that more than one test per normal stress is necessary if a more accurate and reliable interface shear strength value is to be obtained. Carefully controlled inter-laboratory geosynthetic interface shear strength comparison tests undertaken on large direct shear devices that differ in the kinematic degrees of freedom of the top box, showed the fixed top box design to consistently over estimate the available interface shear strength compared to the vertically movable top box design. Results obtained from measurement of the normal stress on the interface during shear with use of load cells in the lower box of the fixed top box design, raise key questions on the accuracy, reliability and proper interpretation of the interface shear strength data used in landfill design calculations. Tests on the geocomposite/sand interface have shown the interface friction angle to vary with the orientation of the geocomposite's main core, in relation to the direction of shearing. Close attention needs to be paid to the onsite geocomposite placement in confined spaces and capping slope corners, as grid orientation on the slope becomes particularly important when sliding is initiated. Attempts to measure the pore water pressure during staged consolidation and shear along a clay/geomembrane interface in the large direct shear device suggest that this interface is a partial drainage path.
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Liang, Hongwei. "Development of microwave and millimeter-wave pin grid array and ball grid array packages." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/14867.
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Silva, Humberto de Alencar Pizza da. "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." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-08062011-112922/.
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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.
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Sabillón, Antúnez Carlos Francisco. "Mathematical optimization of unbalanced networks operation with smart grid devices." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/154075.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
As redes de distribuição de energia elétrica devem estar preparadas para fornecer um serviço econômico e confiável a todos os clientes, bem como para integrar tecnologias relacionadas à geração distribuída, armazenamento de energia e veículos elétricos. Uma representação adequada da operação das redes de distribuição, considerando as tecnologias de redes inteligentes, é fundamental para atingir esses objetivos. Este trabalho apresenta formulações matemáticas para a operação em regime permanente das redes de distribuição, que consideram o desequilíbrio de redes trifásicas. Modelos matemáticos da operação de dispositivos relacionados à redes inteligentes presentes em redes de distribuição são desenvolvidos (e.g., dispositivos de controle volt-var, sistemas de armazenamento de energia e veículos elétricos). Além disso, características relacionadas à dependência da tensão das cargas, geração distribuída e limites térmico e de tensão também estão incluídos. Essas formulações constituem um marco matemático para a análise de otimização da operação das redes de distribuição de energia elétrica, o que possibilita modelar os processos de tomada de decisões. Objetivos diferentes relacionados a aspectos técnicos e/ou econômicos podem ser almejados dentro deste marco; Além disso, a extensão para otimização multi-período e multi-cenário é discutida. Os modelos apresentados são construídos com base em formulações de programação linear inteira mista, evitando o uso de formulações não-lineares inteiras mistas convencionais. A aplicação do marco apresentado é ilustrada em abordagens de controle para coordenação de carregamento de veículos elétricos, controle de magnitude de tensão e controle de geração distribuída renovável. Diversos métodos são desenvolvidos, com base no marco de otimização matemática, para otimizar a operação de sistemas de distribuição desbalanceados, considerando não apenas diferentes penetrações de veículos elétricos e fontes de energia renováveis, mas também a presença de sistemas de armazenamento e dispositivos de controle volt-var. A este respeito, o agendamento dinâmico e a otimização multi-período de janela rolante são frequentemente usados para alcançar uma operação ótima na rede. A eficácia e robustez das metodologias, bem como a confiabilidade do marco de otimização matemática, são verificados usando vários sistemas de teste (e.g., 123-node, 34-node e 178-node) com nós de média e baixa tensão, diferentes janelas de controle e várias disponibilidades de controle relacionadas aos dispositivos de rede inteligente.
Electric distribution networks should be prepared to provide an economic and reliable service to all customers, as well as to integrate technologies related to distributed generation, energy storage, and plug-in electric vehicles. A proper representation of the electric distribution network operation, taking into account smart grid technologies, is key to accomplish these goals. This work presents mathematical formulations for the steady-state operation of electric distribution networks, which consider the unbalance of three-phase grids. Mathematical models of the operation of smart grid-related devices present in electric distribution networks are developed (e.g., volt-var control devices, energy storage systems, and plug-in electric vehicles). Furthermore, features related to the voltage dependency of loads, distributed generation, and voltage and thermal limits are also included. These formulations constitute a mathematical framework for optimization analysis of the electric distribution network operation, which could assist planners in decision-making processes. Different objectives related to technical and/or economic aspects can be pursued within the framework; in addition, the extension to multi-period and multi-scenario optimization is discussed. The presented models are built based on mixed integer linear programming formulations, avoiding the use of conventional mixed integer nonlinear formulations. The application of the presented framework is illustrated throughout control approaches for plug-in electric vehicle charging coordination, voltage magnitude control, and renewable distributed generation control. Several methods are developed, based on this framework, to optimize the operation of unbalanced distribution systems considering not only different penetrations of electric vehicles and renewable energy sources but also the presence of storage systems and volt-var control devices. In this regard, dynamic scheduling and rolling multi-period optimization are often used to achieve optimal economic operation in the grid. The effective and robustness of the methodologies, as well as the reliability of the mathematical framework, are verified using many test systems (e.g., 123-node, 34-node, and 178-node) with medium and low voltage nodes, different operation control time frames, and several control availabilities related to the smart grid devices.
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Mikl, Marek. "Návrh přídavného pokládacího zařízení pro aplikaci rolí skelné geomříže GlasGrid®." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-442818.
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The diploma thesis deals with the design of an additional device for the application of glass grid rolls GlasGrid® and functional calculations. Diploma thesis was created in collaboration with company Saint-Gobain ADFORS. The designed equipment must be able to lay all the currently produced sizes of the rolls, connectable to the widest possible range of laying machines and must be possible to transport the equipment over a longer distance. The laying equipment must also comply with the strength analysis and functional calculations.
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Guan, Tao. "A system architecture to provide enhanced grid access for mobile devices." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/264489/.
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Formby, David. "A physical overlay framework for insider threat mitigation of power system devices." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53107.
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Nearly every aspect of modern life today, from businesses, transportation, and healthcare, depends on the power grid operating safely and reliably. While the recent push for a “Smart Grid” has shown promise for increased efficiency, security has often been an afterthought, leaving this critical infrastructure vulnerable to a variety of cyber attacks. For instance, devices crucial to the safe operation of the power grid are left in remote substations with their configuration interfaces completely open, providing a vector for outsiders as well as insiders to launch an attack. This paper develops the framework for an overlay network of gateway devices that provide authenticated access control and security monitoring for these vulnerable interfaces. We develop a working prototype of such a device and simulate the performance of deployment throughout a substation. Our results suggest that such a system can be deployed with negligible impact on normal operations, while providing important security mechanisms. By doing so, we demonstrate that our proposal is a practical
and efficient solution for retro-fitting security onto crucial power system devices.
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Sánchez, Reátegui Rafael. "Porphyrins based detection of NH3 and CO, using field effect grid gate devices." Thesis, Linköping University, Applied Physics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-56245.
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Porphyrins consist of twenty-atom rings containing four nitrogen atoms and can be used as sensor to detect odours and gases.
This thesis investigates whether or not porphyrins can be used as functional materials on grid gate devices. Drops of PVC embedded porphyrins were deposited on the surface of a grid gate which is a Metal Oxide Semiconductor (MOS) capacitor. In order to detect the gas sensing properties of the porphyrins a light addressable method called Scanning Light Pulse Technique (SLPT) has been used.
Drops of porphyrins were deposited with a stretched capillary tube (1 mm diameter).
The MOS capacitor has been exposed to nitrogen atmosphere as reference environment, while the target gases were carbon monoxide (100 ppm) and ammonia (500 ppm).
The result from the eight porphyrins is that one of them [Pt(II) TPP] has a response for both gases, ammonia induces a change in both the work function and surface resistance, while the carbon monoxide induces only a change in the surface resistance.
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McGuire, Thomas John 1977. "Improved lifetimes and synchronization behavior in multi-grid inertial electrostatic confinement fusion devices." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38527.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
"February 2007."
Includes bibliographical references (p. 251-254).
A high output power source is required for fast, manned exploration of the solar system, especially the outer planets. Travel times measured in months, not years, will require high power, lightweight nuclear systems. The mature nuclear concepts of solidcore fission and fusion Tokamaks do not satisfy the lightweight criteria due to massive radiators and magnets respectively. An attractive alternative is Inertial Electrostatic Confinement fusion. This extremely lightweight option has been studied extensively and to date has produced significant fusion rates of order 1010 reactions per second, but at low power gains, no higher than Q = 10-4. The major loss mechanisms for the state-of-the-art IEC are identified via a detailed reaction rate scaling analysis. The use of a single cathode grid causes short ion lifetimes and operation at high device pressure for simple ion generation both fundamentally limit the efficiency of these devices. Several improvements, including operation at much lower pressure with ion guns and the use of multiple cathode grids, are verified with particle-in-cell modeling to greatly improve the efficiency of IECs. These simulations show that the greatly increased confinement allows for the development of significant collective behavior in the recirculating ions. The plasma self-organizes from an initially uniform state into a synchronized, pulsing collection of ion bunches.
(cont.) In simulations, these bunches are observed to be long-lived with lifetimes on the order of at least a tenth of a second, exceeding 20,000 passes. This represents a 3 order of magnitude improvement in confinement time and device efficiency. The synchronization of a bunch is due to the ion-ion interaction and kinematics of the well-confined IEC. The synchronization between beams is understood to arise from macroscale 'collisions' of bunches coupled with the kinematics of the device. Further, the collective effects limit the space charge buildup and higher densities result in violent ejection from the system. An IEC device which exploits the synchronization effect can achieve high efficiencies and gain, with fusion as the fastest collision timescale. Despite the potential of operation at break-even, the total power output is limited by the relatively low achievable core densities. The immediate application for this work is inexpensive neutron generators useful for medical, security, research, and industrial applications, but use much less power than a state-of-the-art IEC. The results of this thesis suggest two future research directions. First, neutralization of portions of the ion flow could allow greater densities and increase power output to levels required for space travel. Second, the idea of using kinematics coupled with ion-ion collisions to control thermalization may be applied to other plasma confinement concepts.
by Thomas J. McGuire.
Ph.D.
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Asok, Kumar Aarthi. "TECHNICAL AND ECONOMIC IMPACTS OF DISTRIBUTED GENERATORS AND ENERGY STORAGE DEVICES ON THE ELECTRIC GRID." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11142008-151157/.
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In recent years, Distributed Generators (DGs) and energy storage devices have gained more popularity due to growing energy and environmental concerns. Interconnection of DGs and storage devices in an electricity grid impacts its performance under steady state and transient conditions. This research aims at analyzing the impacts of distributed generators and energy storage devices on the transient stability of the grid. Battery and ultra-capacitor technologies have been taken as the two types of storage devices and their electrical characteristics have been modeled using Simulink. Impact of these devices has been analyzed by connecting them to the system by means of suitable power electronic converters. The developed methodology has been evaluated using small test systems in MATLAB/Simulink. Transient stability of the test systems has been assessed for different types and locations of faults as well as for different penetration levels of the DGs, with and without the energy storage devices. Impact on the system transient stability has been analyzed based on transient response of the generator rotor speed deviation, rotor angle and terminal voltage of the DGs. Finally, economic analyses have been carried out for different options of DGs, based on wind, diesel and biomass, along with the energy storage devices. Results indicate that the presence of DGs and storage devices enhances the transient stability of the system in most of the cases.
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Barik, Tapas Kumar. "Modern Adaptive Protection and Control Techniques for Enhancing Distribution Grid Resiliency." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103644.
Full textAbstract:
Power distribution systems have underwent a lot of significant changes in the last two
decades. Wide-scale integration of Distributed Energy Resources (DERs) have made the
distribution grid more resilient to abnormal conditions and severe weather induced outages.
These DERs enhance the reliability of the system to bounce back from an abnormal situation
rather quickly. However, the conventional notion of a radial system with unidirectional
power flow does not hold true due to the addition of these DERs. Bidirectional power flow
has challenged the conventional protection schemes in place. The most notable effects on
the protection schemes can be seen in the field of islanding or Loss of Mains(LOM) detection
and general fault identification and isolation. Adaptive protection schemes are needed to
properly resolve these issues. Although, previous works in this field have dealt with this
situation, a more comprehensive approach needs to be taken considering multiple topologies
for developing adaptive protection schemes. The most common protective devices widely
deployed in the distribution system such as overcurrent relays, reverse power relays at Point
of Common Coupling(PCC), fuses, reclosers and feeder breakers need to studied in implementing
these schemes.
The work presented in this dissertation deals with simulation based and analytical approaches
to tackle the issues of islanding and adaptive protection schemes. First we propose a multiprinciple
passive islanding detection technique which relies on local PCC measurements, thus
reducing the need of additional infrastructure and still ensuring limited Non Detection Zone
(NDZ). The next step to islanding detection would be to sustain a islanded distribution
system in order to reduce the restoration time and still supply power to critical loads. Such
an approach to maintain generator load balance upon islanding detection is studied next by
appropriate shedding of non-critical and low priority critical loads based upon voltage sensitivity
analysis. Thereafter, adaptive protection schemes considering limited communication
dependency is studied with properly assigning relay settings in directional overcurrent relays
(DOCRs), which are one of the most widely deployed protective devices in distribution
systems by catering to multiple topologies and contingencies. A simulation based technique
is discussed first and then an analytical approach to solve the conventional optimal relay
coordination problem using Mixed Integer Linear Programming (MILP) with the usage of
multiple setting groups is studied. All these approaches make the distribution more robust
and resilient to system faults and ensure proper fault identification and isolation, ensuring
overall safety of system.Doctor of Philosophy
With widespread integration of inverter-based distributed energy resources (DERs) in the distribution grid, the conventional protection and control schemes no longer hold valid. The necessity of an adaptive protection scheme increases as the DER penetration in the system increases. Apart from this, changes in system topology and variability in DER generation, also change the fault current availability in the system in real-time. Hence, the protection schemes should be able to adapt to these variations and modify their settings for proper selectivity and sensitivity towards faults in the system, especially in systems with high penetration of DERs. These protection schemes need to be modified in order to properly identify and isolate faults in the network as well as correctly identify Loss of Mains (LOM) or islanding phenomenon. Special attention is needed to plan the next course of action after the islanding occurrence. Additionally, the protective devices in distribution system should be utilized to their maximum capability to create an adaptive and smart protection system. This document elaborately explains the research work pertaining to these areas.
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Falls, Candice. "FRAILTY IN PATIENTS UNDERGOING LEFT VENTRICULAR ASSIST DEVICE IMPLANTATION." UKnowledge, 2019. https://uknowledge.uky.edu/nursing_etds/47.
Full textAbstract:
Heart failure is a progressive condition that affects over 5.7 million Americans and costs associated with heart failure account for 2-3 % of the national health care budget. The high rates of morbidity and mortality along with increased costs from readmissions associated with advanced heart failure have led to the exploration of advanced treatments such as left ventricular assist devices (LVADs). LVADS have demonstrated morbidity and mortality benefit but cost remains extensive with costs per quality-adjusted years > $400,000. With this in mind, it is important to identify those who are most likely to benefit from an LVAD to avoid unfavorable outcomes and cost. Although general guidelines and criteria for patient eligibility have been established, choosing patients for LVAD implantation remains challenging. A new focus on patient selection involves the presence of frailty. While frailty has been studied in the elderly population and in patients undergoing cardiac surgery, frailty in patients undergoing left ventricular assist device (LVAD) remains controversial. The purpose of this dissertation was to examine measures of frailty in patients undergoing LVAD implantation. The specific aims of this dissertation were to: (1) identify a feasible frailty measure in adults with end-stage heart failure who underwent LVAD implantation by testing the hypothesis that frailty would predict 30 day rehospitalization rates using Fried’s criteria, Short Physical Performance Battery test, handgrip strength, serum albumin and six minute walk test (2) Determine whether frailty measures improve 3 months post LVAD implantation (3) compare sensitivity of these three measures to change in frailty.
Surgical approaches, including heart transplantation and LVAD implantation, for patients with end-stage heart failure was discussed in this dissertation. Data from two subsets of participants who underwent LVADS at the University of Kentucky between 2014 and 2017 were included in the analysis for this dissertation. In the first study, we found that none of the measures are good predictors of frailty in patients with advanced heart failure who undergo LVAD implantation. Handgrip was the only marker of frailty that predicted 30 day readmission but the relationship was a negative association. In the second study, six-minute walk and low serum albumin levels reflect short-term improvement in frailty. These simple measures may be used to determine those patients who are responsive to LVAD implantation.
The findings of these studies filled some gaps in our understanding of markers of frailty in patients undergoing LVADs. We gained a better understanding of which markers of frailty are likely to improve in most people after LVAD implantation and thus frailty should not preclude candidate selection for an LVAD. Subsequently, more research is needed to investigate these markers and outcomes.
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Masood, Tariq. "Improvement of voltage and power flow control in the GCC power grid by using coordinated FACTS devices." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.589638.
Full textAbstract:
This work presents HVDC/FACTS control device implementation framework in the Gulf cooperative council’s countries. It comprises of five layers of FACTS control devices (STATCOM, SSSC, UPFC, HVDC and centralized/De-centralized Control). This five-layer architecture is designed in order to configure and produce the desired results; based on these outcomes, GCC power system network control and operational problems can be identified and addressed within the control architecture on the GCC power grid. In the context of power FACTS-FRAME, this work is to identify and determine a number of power systems operational and control problems which are persistent on the GCC power grid e.g. poor voltage quality (SAG-Swell), poor load flow control, and limited power transfer capacity issues. The FACTS-FRAME is configured and synthesized by integrating multiple FACTS control devices (STATCOM, SSSC, UPFC) in parallel at different locations on the GCC power grid in order to meet stringent power system control and operational requirements with improved power transfer capacity, controllability and reliability. The mathematical models are derived to indentify and determine operational constraints on the GCC power grid by incorporating real-time and estimated data and the acquired desired results. Herein, FACTS-FRAME is designed to handle distributed computation for intensive power system calculation by integrating multiple FACTS devices on multiple networks within the GCC power network. Distributed power flow algorithms are also derived in order to understand and implement centralized and decentralized control topologies as appropriate. The simulation results indicate the feasibility of FACTS devices implementation and their potential benefits under current operating conditions on the GCC power grid.
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Foulkes, Philip James. "A grid based approach for the control and recall of the properties of IEEE 1394 audio devices." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1004836.
Full textAbstract:
The control of modern audio studios is complex. Audio mixing desks have grown to the point where they contain thousands of parameters. The control surfaces of these devices do not reflect the routing and signal processing capabilities that the devices are capable of. Software audio mixing desk editors have been developed that allow for the remote control of these devices, but their graphical user interfaces retain the complexities of the audio mixing desk that they represent. In this thesis, we propose a grid approach to audio mixing. The developed grid audio mixing desk editor represents an audio mixing desk as a series of graphical routing matrices. These routing matrices expose the various signal processing points and signal flows that exist within an audio mixing desk. The routing matrices allow for audio signals to be routed within the device, and allow for the device’s parameters to be adjusted by selecting the appropriate signal processing points. With the use of the programming interfaces that are defined as part of the Studio Connections – Total Recall SDK, the audio mixing desk editor was integrated with compatible DAW applications to provide persistence of audio mixing desk parameter states. Many audio studios currently use digital networks to connect audio devices together. Audio and control signals are patched between devices through the use of software patchbays that run on computers. We propose a double grid-based FireWire patchbay aimed to simplify the patching of signals between audio devices on a FireWire network. The FireWire patchbay was implemented in such a way such that it can host software device editors that are Studio Connections compatible. This has allowed software device editors to be associated with the devices that are represented on the FireWire patchbay, thus allowing for studio wide control from a single application. The double grid-based patchbay was implemented such that it can be hosted by compatible DAW applications. Through this, the double grid-based patchbay application is able to provide the DAW application with the state of the parameters of the devices in a studio, as well as the connections between them. The DAW application may save this state data to its native song files. This state data may be passed back to the double grid-based patchbay when the song file is reloaded at a later stage. This state data may then be used by the patchbay to restore the parameters of the patchbay and its device editors to a previous state. This restored state may then be transferred to the hardware devices being represented by the patchbay.
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Isaiadis, Stavros. "Dynamic service aggregation for integrating mobile and limited devices into hybrid grids." Thesis, University of Westminster, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442107.
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Lakshminarayanan, Anand. "Analysis of the sensitivity of photochemical airshed modeling to grid size and spatial and temporal distributions aof mobile source emissions." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/20835.
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Augspurger, Michael. "Improving the performance of finned latent heat thermal storage devices using a Cartesian grid solver and machine-learning optimization techniques." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6048.
Full textAbstract:
The high energy density and stable temperature fields of latent heat thermal storage devices (LHTSD) make them promising in a range of applications, including solar energy storage, solar cooking, home heating and cooling, and thermal buffering. The chief engineering challenge in building an effective LHTSD is to find a way to complement the storage capabilities provided by the low-conductivity phase-change material with a suitable enhanced heat transfer mechanism.
The principal aim of this project is to develop a tool to improve the design of a small-scale LHTSD, such as one that might be used in solar cooking for a family. An effective small-scale storage device would need to absorb solar energy quickly, release the energy at a high temperature, be affordable, and be manageable within a small household. An LHTSD using solar salts fulfills the latter two requirements: solar salts, a near-eutectic mixture of NaNO3 and KNO3 (60/40% by mass) commonly used in thermal storage applications, are inexpensive and widely available, and the use of latent heat storage means a relatively small chamber can hold enough energy to cook a family meal. The challenge, however, is to design a device that absorbs and releases energy from the solar salts, which have a very low thermal conductivity. The most practical tool to improve the spread of heat through the salts is a finned metal core within the LHTSD.
This project uses numerical simulation to determine the most effective design of this finned core. A Cartesian grid solver is developed that is capable of simulating the convection-dominated melting processes within the storage device. The phase boundary is tracked using the enthalpy method, and conjugate heat transfer is calculated with a strongly coupled implicit scheme.
A number of techniques are then used to with this solver in order to better understand the factors that affect the performance of a LHTSD and to improve the design of such devices. The thesis is organized as an introductory section followed by three case studies. In the first section, the project is introduced, and the governing equations and core numerical methods are described. In addition, a set of test simulations demonstrate that results using the developed numerical scheme match those of a range of experimental and numerical benchmarks.
Each of the case studies aims to adapt the numerical scheme to a more specific problem concerning LHTSDs. In the first, the performance of four fin designs are compared over long-term (48 hour) simulations; the aim is to test the potential performance of the four LHTSDs given realistic solar conditions in New Delhi, India. In the second case study, a set of physical experiments are performed in an empty and a finned LHTSD, and matched 3-dimensional numerical simulations are used to explore the thermal, melt, and flow behavior of the solar salts with the chambers. The final study uses the computational scheme to optimize the design of the finned core of an LHTSD over a large parameter space. To optimize the best design, the key parameters are first prescreened to find which three parameters have the largest effect on the objective equation. A machine-learning optimization code using the dynamic Kriging method (DKG) is then used to build a response surface from which the optimized design can be determined.
These three cases demonstrate the potential of the numerical scheme to explore the performance of finned LHTSD designs in a range of ways: the scheme can be used to predict behavior of devices in realistic conditions, to explore the behavior of solar salts during the melting and solidification process, and to determine an optimal design within a large parameter space. In doing so, they show the potential of this tool to help improve the performance and practicality of small-scale LHTSDs.
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Bottura, Riccardo. "Impatto della propagazione elettromagnetica sulle prestazioni delle reti M3N." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2896/.
Full textAbstract:
Con il termine Smart Grid si intende una rete urbana capillare che trasporta energia, informazione e controllo, composta da dispositivi e sistemi altamente distribuiti e cooperanti. Essa deve essere in grado di orchestrare in modo intelligente le azioni di tutti gli utenti e dispositivi connessi al fine di distribuire energia in modo sicuro, efficiente e sostenibile. Questo connubio fra ICT ed Energia viene comunemente identificato anche con il termine
Smart Metering, o Internet of Energy. La crescente domanda di energia e l’assoluta necessità di ridurre gli impatti ambientali (pacchetto clima energia 20-20-20 [9]), ha creato una convergenza di interessi scientifici, industriali e politici sul tema di come le tecnologie ICT possano abilitare un processo di trasformazione strutturale di ogni fase del ciclo energetico: dalla generazione fino
all’accumulo, al trasporto, alla distribuzione, alla vendita e, non ultimo, il consumo intelligente di energia.
Tutti i dispositivi connessi, diventeranno parte attiva di un ciclo di controllo esteso alle grandi centrali di generazione così come ai comportamenti dei singoli utenti, agli elettrodomestici di casa, alle auto elettriche e ai sistemi di micro-generazione diffusa. La Smart Grid dovrà quindi appoggiarsi su una rete capillare di comunicazione che fornisca non solo la connettività fra i dispositivi, ma anche l’abilitazione di nuovi servizi energetici a valore aggiunto.
In questo scenario, la strategia di comunicazione sviluppata per lo Smart Metering dell’energia elettrica, può essere estesa anche a tutte le applicazioni di telerilevamento e
gestione, come nuovi contatori dell’acqua e del gas intelligenti, gestione dei rifiuti, monitoraggio dell’inquinamento dell’aria, monitoraggio del rumore acustico stradale, controllo continuo del sistema di illuminazione pubblico, sistemi di gestione dei parcheggi
cittadini, monitoraggio del servizio di noleggio delle biciclette, ecc. Tutto ciò si prevede possa contribuire alla progettazione di un unico sistema connesso, dove differenti dispositivi eterogenei saranno collegati per mettere a disposizione un’adeguata struttura a basso costo e
bassa potenza, chiamata Metropolitan Mesh Machine Network (M3N) o ancora meglio Smart City.
Le Smart Cities dovranno a loro volta diventare reti attive, in grado di reagire agli eventi esterni e perseguire obiettivi di efficienza in modo autonomo e in tempo reale. Anche per esse è richiesta l’introduzione di smart meter, connessi ad una rete di comunicazione broadband e
in grado di gestire un flusso di monitoraggio e controllo bi-direzionale esteso a tutti gli apparati connessi alla rete elettrica (ma anche del gas, acqua, ecc).
La M3N, è un’estensione delle wireless mesh network (WMN). Esse rappresentano una tecnologia fortemente attesa che giocherà un ruolo molto importante nelle futura generazione
di reti wireless. Una WMN è una rete di telecomunicazione basata su nodi radio in cui ci sono minimo due percorsi che mettono in comunicazione due nodi. E’ un tipo di rete robusta e che offre ridondanza. Quando un nodo non è più attivo, tutti i rimanenti possono ancora comunicare tra di loro, direttamente o passando da uno o più nodi intermedi. Le WMN rappresentano una tipologia di rete fondamentale nel continuo sviluppo delle reti radio che denota la divergenza dalle tradizionali reti wireless basate su un sistema centralizzato come le reti cellulari e le WLAN (Wireless Local Area Network). Analogamente a quanto successo per le reti di telecomunicazione fisse, in cui si è passati,
dalla fine degli anni ’60 ai primi anni ’70, ad introdurre schemi di rete distribuite che si sono evolute e man mano preso campo come Internet, le M3N promettono di essere il futuro delle reti wireless “smart”. Il primo vantaggio che una WMN presenta è inerente alla tolleranza alla caduta di nodi della rete stessa. Diversamente da quanto accade per una rete cellulare, in cui la caduta di una Base Station significa la perdita di servizio per una vasta area geografica, le WMN sono provviste di un’alta tolleranza alle cadute, anche quando i nodi a cadere sono più di uno.
L'obbiettivo di questa tesi è quello di valutare le prestazioni, in termini di connettività e throughput, di una M3N al variare di alcuni parametri, quali l’architettura di rete, le tecnologie utilizzabili (quindi al variare della potenza, frequenza, Building Penetration Loss…ecc) e per diverse condizioni di connettività (cioè per diversi casi di propagazione e densità abitativa). Attraverso l’uso di Matlab, è stato quindi progettato e sviluppato un simulatore, che riproduce le caratteristiche di una generica M3N e funge da strumento di valutazione delle performance della stessa. Il lavoro è stato svolto presso i laboratori del DEIS di Villa Grifone in collaborazione con la FUB (Fondazione Ugo Bordoni).
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Dengiz, Thomas [Verfasser], and W. [Akademischer Betreuer] Fichtner. "Optimization approaches for exploiting the load flexibility of electric heating devices in smart grids / Thomas Dengiz ; Betreuer: W. Fichtner." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1232324027/34.
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Strauss, Ilse. "Typically developing 4-year-old children with AAC systems using different language organization techniques." Diss., Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-08042008-174658.
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Moravčík, Martin. "Modelování a simulace hybridní mikro sítě v prostředí PSCAD." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219410.
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In the opening part of this master´s thesis there is given concept, description, usage and advantages of micro hybrid grids in comparison to micro grids and there are evolution steps towards hybrid grid. There is also a mention about economics of operation of these grids. In the second part of this thesis there are descriptions of devices that are suitable for usage in micro hybrid grids with emphasis on generators and accumulation possibilities. In the next part of this thesis there is given an approach and description for modeling of various components of hybrid grids in PSCAD environment. In the next part of this thesis there are given simulation results that were conducted on created model. Especially power balance in 24 hour operation of the grid with method for determining suitable size of accumulation and installed capacity of photovoltaics. And next there are showed responses from change of power from photovoltaics, next there is a transition to islanded mode and last there is showed the behavior of converter when the limits of accumulation are reached. In the final part of this thesis there are conclusions, fulfillment of goals of this thesis and possibilities of further study.
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Silveira, Miguel Francisco da. "Análise do impacto da geração distribuída sobre a rede elétrica de distribuição devido à utilização de geradores fotovoltaicos." Universidade do Vale do Rio dos Sinos, 2013. http://www.repositorio.jesuita.org.br/handle/UNISINOS/4426.
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Miguel Francisco da Silveira.pdf: 1561110 bytes, checksum: dcb1486a17c6616e1fcf6803ce1272ec (MD5)Made available in DSpace on 2015-07-13T18:32:37Z (GMT). No. of bitstreams: 1 Miguel Francisco da Silveira.pdf: 1561110 bytes, checksum: dcb1486a17c6616e1fcf6803ce1272ec (MD5) Previous issue date: 2013-01-31
Milton Valente
UNISINOS - Universidade do Vale do Rio dos Sinos
Muito tem se falado sobre o uso de fontes alternativas de energia e do uso de pequenas fontes em geração distribuída (GD), especialmente com a nova legislação brasileira que agora considera esta possibilidade. O aproveitamento da energia solar vem crescendo ao longo dos últimos anos, tanto através de seu uso como fonte térmica, quanto através da geração fotovoltaica, baseado no baixo impacto ambiental desta fonte de energia. Este trabalho tem por objetivo estudar o impacto da geração distribuída no sistema de distribuição de energia elétrica pelo uso de geradores fotovoltaicos conectados diretamente à rede de distribuição. O estudo é realizado em regime permanente, sob o ponto de vista elétrico, em um alimentador específico, considerando curvas típicas propostas para dias ensolarados e encobertos. Para esta análise foi utilizada uma base de dados de um ano, com dados de irradiância e de temperatura do ar ambiente coletados na cidade de Porto Alegre - RS entre Julho de 2004 e Junho de 2005. Esta base de dados serviu para estabelecer as curvas típicas de geração de um dia ensolarado e de um dia encoberto, através de uma metodologia desenvolvida. Com o uso destas curvas típicas foi definido o padrão de geração fotovoltaica em um dia ensolarado e em um dia encoberto. Após a definição deste padrão de geração foi possível analisar o impacto em um alimentador específico, localizado na cidade de Viamão - RS. A análise do impacto na rede considerou a influência que a geração distribuída ocasiona nos níveis de tensão nos diferentes nós ao longo do alimentador. Foi considerada uma penetração de 20% de GD, em dois diferentes horários para um dia ensolarado e para um dia encoberto. A potência gerada foi normalizada em relação à potência consumida nos diferentes pontos do alimentador. Os impactos observados na rede de distribuição não foram relevantes, entretanto a geração fotovoltaica contribuiu levemente para a melhora em alguns níveis de tensão que estavam na faixa crítica, em alguns cenários analisados.
Alternative sources of energy and distributed generation (DG) are current subjects, especially in Brazil where the regulations had just changed and now the possibility of DG and compensation of energy can be considered. The use of solar energy has been increased along the last years, thus as a heat source or as photovoltaic (PV) generation, based mainly on the low environmental impact of this energy source. This essay aims to study the impact of distributed generation in the electrical energy distribution system caused by the use of photovoltaic generators connected straight to the distribution grid. The study is done in steady state condition, in a specific feeder, considering typical curves proposed for sunny and cloudy days. A data base of irradiance and temperature of air ambient of one year had been used for this analysis. The data had been collected in the city of Porto Alegre – RS – Brazil, from July 2004 to June 2005. This data base was used to establish the generation typical curves of sunny and cloudy days through a methodology developed. The photovoltaic generation standards for sunny and cloud days had been defined by the use of these typical curves. With these standards were possible to analysis the impact in a specific feeder, located in the city of Viamão – RS – Brazil. The analysis of the impact in the grid considered the influence of distributed generation could cause on voltage levels at different bars along the feeder. It had been considered a penetration of DG of 20%, in two different hourly times for each day, sunny and cloudy typical curves. The power generated had been normalized related to the power consumed in different points of the feeder. The impact observed in the distribution grid is not relevant. However, the distribution generation did contribute to slightly raise some voltage levels that are already among the critical zone, in some of the sets analysed.
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Lohrmann, Peter J. "Energy-Efficient Interactive Ray Tracing of Static Scenes on Programmable Mobile GPUs." Digital WPI, 2007. https://digitalcommons.wpi.edu/etd-theses/60.
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Mobile technology is improving in quality and capability faster now than ever before. When first introduced, cell phones were strictly used to make voice calls; now, they play satellite radio, MP3s, streaming television, have GPS and navigation capabilities, and have multi-megapixel video cameras. In the near future, cell phones will have programmable graphics processing units (GPU) that will allow users to play games similar to those currently available for top-of-the-line game consoles. Personal digital assistants enable users with full email, scheduling, and internet browsing capabilities in addition to those features offered on cell phones. Underlying all this mobile technology and entertainment is a battery whose technology has just barely tripled in the past 15 years, compared to available disk capacity that has increased over 1,000-fold. Ray tracing is a rendering technique used to generate photorealistic images that include reflections, refraction, participating media, and can fairly easily be extended to include photon mapping for indirect illumination and caustics. In recent years, ray tracing has been implemented on the GPU using various acceleration structures to facilitate rendering. Until now, all studies have used build time and achievable frame rates to determine which acceleration structure is best for ray tracing. We present the very first results comparing both CPU and GPU raytracing using various acceleration structures in terms of energy consumption. By exploring per-pixel costs, we provide insight on the energy consumption and frame rates that can be experienced on cell phones and other mobile devices based on currently available screen resolutions. Our results show that the choice in processing unit has the greatest affect on energy and time costs of ray tracing, followed by the size of the viewport used, and the choice of acceleration structure has the least impact on efficiency. For mobile devices enabled with a programmable GPU, whether it is a cell phone, PDA, or laptop computer, a bounding volume hierarchy implemented on the GPU is the most energy-efficient acceleration structure for ray tracing. Ray tracing on cellular phones with smaller screen resolutions is most energy-efficient using a CPU-based Kd-Tree implementation.
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Santos, Frederico Cassis Ribeiro. "Análise de execução de aplicações paralelas em grades móveis com restrições de processamento e bateria." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-05102016-102814/.
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Existem atualmente diversas propostas para integração de dispositivos móveis em uma grade computacional, porém vários problemas são observados em tais ambientes. Esta dissertação mantém o foco em um problema, a restrição sobre a quantidade de energia despendida na execução das aplicações, ao utilizar esses dispositivos móveis como provedores de recursos em uma grade computacional que fornece processamento para aplicações paralelas. Para tanto, este trabalho propõe um método para estimar o consumo de energia das aplicações considerando que elas utilizam um determinado conjunto de operações as quais estão presentes na grande maioria das aplicações paralelas (operações matemáticas e alocação de memória). Com base no método proposto, dois dispositivos móveis foram estudados e foi criada uma representação do consumo de energia utilizando-se de métodos de regressão. Para validar os modelos, duas aplicações foram analisadas e o consumo de energia real foi comparado ao consumo estimado. O modelo criado apresentou resultados próximos ao medido, mostrando um aumento entre 6% e 14,24% em relação ao resultado medido.Nowadays, there are different proposals to integrate mobile devices in a computational grid, although several problems are introduces. This dissertation focus on the energy limitation problem when using mobile devices to provide resources, such as processing power to run parallel applications. It also proposes a method to estimate energy consumption for a task that needs to be executed in this environment. To achieve this goal two mobile devices were used as a test case and a representation of its energy consumption was created running benchmarks and using regression techniques. To validate the model created, two applications were executed and had the measured values compared to the estimated ones. The estimation showed a raise between 6 and 14.24 percent.
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Wistedt, Johan. "Digital secondary substations with auto-configuration of station monitoring through IEC 61850 and CIM." Thesis, Uppsala universitet, Elektricitetslära, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-360513.
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This thesis explore the possibility to automate a process for configuration of secondary substations monitoring and control. By using a network information system (NIS), information of secondary substations can be extracted, such as feeder naming, primary equipment type, rating and model. From this information an automated process of configuring the secondary substation is possible, which open up the possibility to cost-efficiently digitalise the distribution grid. In the project, the standard IEC 61850 for configuration of communications of intelligent electrical devices was used to automate and standardize the process. The process starts with a extracted IEC 61970 CIM file from the NIS. The IEC 61970 CIM file is converted into a IEC 61850 SCL file through an system engineering tool. The configuration is based of information from the NIS, where the models and types of the equipments decides what type of functionality that is needed for the secondary substation. With help of the created SCL file hardware and human-machine interface (HMI) was configured, creating a full functional system for the secondary substation monitoring and control equipment. The usage of 400V capable input module together with bus couplers, configured in IEC 61850, lowers the configuration needed for the hardware. The usage of SCL files also helps automate the creation of HMI for the secondary substation through IEC 61850 based tools in SCADA software. Creating views of both single-line diagrams as well as digital representation of the secondary substation outgoing feeders with measured values on display. The result of the project helps show NIS information is sufficient and standards mature enough to allow an almost fully automated system. Lowering the total time spent on each stations configuration to around two hours. Leading the way for future development of automating software for configurations of the secondary substations.
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Mahmoud, Thair. "Optimal power generation in microgrids using agent-based technology." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/599.
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The existing power grids that form the basis of the respective electrical power infrastructures for various states and nations around the world, are expected to undergo a period of rapid change in the near future. The key element driving this change is the emergence of the Smartgrid. The Smartgrid paradigm represents a transition towards an intelligent, digitally enhanced, two-way power delivery grid. The aim of the Smartgrid is to promote and enhance the e_cient management and operation of the power generation and delivery facilities, by incorporating advanced communications, information technology, automation, and control methodologies into the power grid proper. Smartgrid's are currently an active topic for research, where the research is strongly focused on developing new technologies such as: demand response, power generation management, pricing modelling and energy markets participation, power quality, and self-healing scenarios. In recent times, in both the United States of America and Europe, many new projects have begun which are specifically directed towards developing “Smartgrid” technologies. In Australia, the Federal Government has recently initiated funding plans to promote the commercialisation of renewable energy. In order to exploit these developments, Edith Cowan University (ECU); which is a High Voltage (HV) customer for the major utility network of Western Australia, and which owns its own transformers and Low Voltage (LV) network; is planning to integrate renewable energy suppliers within its LV network.
The aim of this research is to introduce a smart decision making system, which can manage the operation of disparate power generation sources installed on a LV network (microgrid); such as that owned by ECU on its campuses. The proposed energy management system is to gather data in real-time, and it must be capable of anticipating and optimising energy needs for each operational scenario that the microgrid might be expected to experience. The system must take into account risk levels, while systematically favouring low economic and environmental costs. A management system application, based on autonomous and distributed controllers, is investigated in a virtual environment. The virtual environment being a full-scale simulation of ECU's microgrid; with solar panels, wind turbines, storage devices, gas gen-sets, and utility supply. Hence the simulation studies were conducted on the basis of realistic demand trends and weather conditions data.
The major factors for reducing the cost of generation in the case study, were identified as being: 1) demand forecasting; 2) generation scheduling; 3) markets participation; and 4) autonomous strategies configuration, which is required to cope with the unpredictable operation scenarios in LV networks. Due to the high uncertainty inherent within the operational scenarios; an Artificial Intelligence (AI) deployment for managing the distributed sub-systems was identified as being an ideal mechanism for achieving the above mentioned objectives. Consequently it is proposed that Multi-Agent System (MAS) technology be deployed, to enable the system to respond dynamically to the unpredictable operational conditions by updating the method of analysis. The proposed system is to behave in a strategic manner when dealing with the expected operational scenarios, by aiming to achieve the lowest possible cost of power generation for the microgrid. The simulated system is based on realistic operational scenarios, which have been scaled to suit the size and type of load in the case study. The distributed intelligent modules have proven to be successful in achieving the potential benefits of the dynamic operational conditions, by minimising the cost of power generation.
The distributed intelligent modules, which form the basis of the proposed management systems, have been designed to perform the following functions:
1. Provide accurate demand forecasts through the utilisation of an AI-based adaptive demand forecasting model. The novel demand-forecast modelling technique, which was introduced to model demand in the case study, has been utilised to supply reasonably accurate demand forecasts to other stages of processing in the management system. The forecasts are generated from this model, by monitoring and controlling the forecasting error to ensure consistent and satisfactory forecasts.
2. Make optimum decisions concerning the operation of the power generators by considering the economic and the environmental costs. In order to deal with the complexity of the operational conditions, a smart and adaptive generation scheduling method was implemented for the case study. The method was primarily applied to control the charging/ discharging process of the Storage Devices (SDs) among the other generators. The proposed method aims at controlling the resources, and extracting the benefit of having an hourly based variable generation cost.
3. Integrate the microgrid into the electricity market, in order to enable the microgrid to offer its spinning and non-spinning power generation reserve as Ancillary Services (AS) to the grid. To this end, studying the operational mechanisms of the Australian market was essential prior to building the proposed market participation rules which form an integral part of the proposed management system. As a result we used the market data, by approaching the market operators to create a semi-realistic competitive market environment for our simulations. Consequently, a smart and adaptive pricing mechanism, that adapts the AS prices to the amount of electricity on offer, and the level of demand in the market has been presented.
The motivation for introducing the proposed management system, is to achieve a transition plan for current microgrids, so that they can have a commercial connection to the future Smartgrid. The results obtained in this work show that there is a signi_cant economic and environmental advantage to be gained from utilising intelligence when managing electricity generation within a power grid. As a consequence, selecting the appropriate management strategy is fundamental to the success of the proposed management system. In conclusion, modelling of the proposed strategies using MAS technology has proven to be a successful approach, and one that is able to reflect the human attitude; in making critical decisions and in reducing the cost of generation.
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Baradar, Mohamadreza. "On the Efficiency and Accuracy of Simulation Methods for Optimal Power System Operation : Convex Optimization Models for Power System Analysis, Optimal Utilization of VSC-type DC Wind Farm Grids and FACTS Devices." Doctoral thesis, KTH, Elektriska energisystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166383.
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Recently, significant changes in electric power systems such as rapid developmentof smart grid and electricity market and integration of non-dispatchablesources have added more complexity to the Power Flow Scheduling (PFS) andPower Balancing (PB) models. For instance, non-dispatchable sources introducean increasing level of uncertainty in the electricity market and power system operation.One of the solutions for handling these uncertainties in the power systemoperation is the improvement of system flexibility through a more efficient operationof power systems. On the other hand, efficient operation can be achieved bywell capturing variable behavior of uncertain sources such as wind power sourceswhich in turn demands efficient and robust PFS/PB models. This way, a moreflexible system, capable of efficiently accommodating higher levels of wind powerchanges, can be achieved. All these factors increase a need for PFS/PB models suchas Power Flow (PF) and Optimal Power Flow (OPF) models which can addressthese new challenges in an efficient, reliable, and economic way while supportingthe power system operation and control. In this regard, various solution methodshave been developed for solving different forms of PF/OPF formulation. The difficultyof solving OPF problems increases significantly with increasing network sizeand complexity. One of these complexities is how to model advanced controllable devices such as HVDC grids and Flexible AC Transmission Systems (FACTS) devices.Accurate handling of these complexities has limited the use of OPF in manyreal-world applications mainly because of its associated computational challenges.The main reasons behind computational challenges are nonlinearity and especiallynon-convexity of constraints representing power system and its components. Inthis regard, OPF problems are classified into two main groups. In the first group,researchers adopt Nonlinear programming (NLP) approach to fully represent thenonlinearity of the power system for the sake of accuracy but with the cost of complexityin the model. Computational and theoretical challenges associated withNLP approaches are then used as a motivation towards developing a more simplifiedOPF model, leading to the second group of OPF models known as LinearProgramming (LP) based OPF models. LP approaches are fast, reliable, and especiallyconvex, and therefore guarantee a global optimum to the simplified OPFproblem. The problem of LP approach to OPF is that the LP solution of OPF may not even be a feasible solution of original nonlinear OPF at all. Another issueassociated with LP models is that complex power system devices such as HVDClinks are difficult to be incorporated. These limitations have restricted the applicationof LP approaches for many OPF problems. According to the mentionedadvantages and disadvantages of NLP and LP based OPF models, what we seeks isan OPF model which can have main advantages of both LP OPF models (Efficientnumerical solvers) and full AC OPF models (Results accuracy). In this thesis, wedevelop convex optimization problems which can be adopted as both PF and OPFmodels which are capable of catching the nonlinear nature of power systems asmuch as possible while can be solved by efficient solution methods such as InteriorPoint Methods (IPMs). These OPF models can incorporate HVDC links, windfarm Multi Terminal HVDC (MTDC) grids, and shunt FACTS devices.QC 20150521
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Melo, Igor Delgado de. "Estimação de estado harmônico para sistemas radiais de distribuição usando medição fasorial sincronizada." Universidade Federal de Juiz de Fora, 2015. https://repositorio.ufjf.br/jspui/handle/ufjf/234.
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Este trabalho objetiva apresentar uma metodologia capaz de estimar os componentes harmônicos em sistemas de distribuição com topologia radial utilizando PMUs (Phasor Measurement Units). Os estados a serem estimados serão as correntes passantes em todas as linhas do sistema em coordenadas retangulares. Uma vez que essas correntes são obtidas, torna-se possível o cálculo de outras grandezas elétricas através das equações de fluxo de potência e leis de Kirchhoff. A metodologia considera poucas unidades de medição fasorial (as PMUs) instaladas efetuando a leitura dos sinais de tensões nodais e correntes nas linhas com distorção harmônica. A fim de restaurar a observabilidade do sistema por completo, são considerados dados históricos de demanda de potência ativa/reativa, os quais serão tratados como restrições de desigualdades excursionando entre um valor mínimo e máximo considerados em um problema de otimização não linear que visa diminuir a diferença entre os valores monitorados pelas PMUs e os calculados pela metodologia. As mencionadas restrições permitem ao estimador o acompanhamento das variações sofridas ao longo do tempo na curva de carga para a frequência fundamental e também para as demais frequências. A abordagem proposta neste trabalho considera a modelagem trifásica de equipamentos e linhas de distribuição, portanto, são modelados os efeitos de acoplamento mútuo entre fases e a operação não linear de equipamentos de eletrônica de potência tiristorizados. O método demonstra eficiência não apenas em estimar os componentes harmônicos de um certo espectro considerado no estudo, como também se mostra uma ferramenta prática de detecção e identificação de fontes harmônicas no sistema elétrico de potência, além de explicitar um exemplo prático do uso de PMUs no que tange ao monitoramento de redes de distribuição, carentes de acompanhamento em tempo real. A metodologia ainda se mostra capaz de ser aliada a grandes estudos contextualizados em qualidade de energia, uma vez que permite a estimação de índices de distorção harmônica.
This work aims to present a methodology which is capable of estimating harmonic components for distribution systems with radial topology, using PMUs (Phasor Measurement Units). The estimated states will be all branch currents of the system expressed in rectangular coordinates. Once these currents are obtained, it is possible to calculate other electrical quantities using power flow equations and also Kirchhoff’s law. The methodology considers the installation of a few number of phasor measurement units which will measure voltage and branch currents signals distorted by harmonic sources. In order to make the whole system observable, historical data of active/reactive power demand will be treated as inequality constraints varying between minimum and maximum limits described in a non linear optimization problem, which aims to minimize the difference between the values monitored by PMUs and the ones calculated by the methodology. The already mentioned constraints allows the accompaniment of the variations occured in a typical load curve during a period of time for the fundamental frequency and also for their multiples, allowing the accompaniment of the harmonic load curve, normally unknown. The proposed approach considers a three-phase modelling of equipments and distribution lines, subject to their mutual coupling effects caused by mutual impedances between the lines. It will also be considered electronic-based devices using thyristors located along the distribution feeder, injecting harmonic currents in the system. The method demonstrates efficiency in estimating the harmonic states of the net and also in detecting and identifying harmonic sources in an eletric power system, besides showing a practical use of PMUs for the monitoring of distribution systems, lacking in information and real-time accompaniment. The method also enables the estimation of power quality indicators such as total harmonic distortion.
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Herůfek, Radek. "Vliv větrných elekrátren na napěťovou stabilitu v kontinentální Evropě." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221337.
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Diplomová práce pojednává o výrobě elektrické energie větrnými elektrárnami a jejím vlivu na napěťovou stabilitu v synchronně propojené elektrizační soustavě kontinentální Evropy. Úvod práce je obecně zaměřen na problematiku větrné energetiky se zaměřením na nejčastěji používané generátory pro větrné turbíny. V další části práce je proveden rozbor instalované kapacity větrných elektráren v zemích synchronně propojené elektrizační soustavy kontinentální Evropy a jsou představeny scénáře růstu větrné energetiky do budoucna. V rámci těchto zemí je také zařazen přehled potenciálu větrné energie na pevnině a na moři. Dále je práce zaměřená na napěťovou stabilitu, kde je pojednáno o kompenzačních prostředcích a možnostech regulace napětí. Závěr teoretické části je věnován možnostem předpovědi počasí a dopadu změn počasí na výrobu elektrické energie. V praktické části diplomové práce byla provedena simulace plánované větrné farmy a sledování jejího vlivu na napěťovou stabilitu v konkrétní části přenosové soustavy.
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Franek, Lešek. "Data koncentrátor pro chytré sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219675.
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The goal is to design data concentrator for Smart Grids. Data Concentrator provides the interface between the server systems of distribution companies and end devices, which are electricity meters, water meters, gas meters and other equipment. There are hardware and software design solutions and there is also discussed creating its own distribution of Linux.
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Gkikas, Nikolaos. "Data Transfer and Management through the IKAROS framework : Adopting an asynchronous non-blocking event driven approach to implement the Elastic-Transfer's IMAP client-server connection." Thesis, KTH, Radio Systems Laboratory (RS Lab), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166740.
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Given the current state of input/output (I/O) and storage devices in petascale systems, incremental solutions would be ineffective when implemented in exascale environments. According to the "The International Exascale Software Roadmap", by Dongarra, et al. existing I/O architectures are not sufficiently scalable, especially because current shared file systems have limitations when used in large-scale environments. These limitations are: Bandwidth does not scale economically to large-scale systems, I/O traffic on the high speed network can impact on and be influenced by other unrelated jobs, and I/O traffic on the storage server can impact on and be influenced by other unrelated jobs. Future applications on exascale computers will require I/O bandwidth proportional to their computational capabilities. To avoid these limitations C. Filippidis, C. Markou, and Y. Cotronis proposed the IKAROS framework. In this thesis project, the capabilities of the publicly available elastic-transfer (eT) module which was directly derived from the IKAROS, will be expanded. The eT uses Google’s Gmail service as an utility for efficient meta-data management. Gmail is based on the IMAP protocol, and the existing version of the eT framework implements the Internet Message Access Protocol (IMAP) client-server connection through the ‘‘Inbox’’ module from the Node Package Manager (NPM) of the Node.js programming language. This module was used as a proof of concept, but in a production environment this implementation undermines the system’s scalability and there is an inefficient allocation of the system’s resources when a large number of concurrent requests arrive at the eT′s meta-data server (MDS) at the same time. This thesis solves this problem by adopting an asynchronous non-blocking event driven approach to implement the IMAP client-server connection. This was done by integrating and modifying the ‘‘Imap’’ NPM module from the NPM repository to suit the eT framework. Additionally, since the JavaScript Object Notation (JSON) format has become one of the most widespread data-interchange formats, eT′s meta-data scheme is appropriately modified to make the system’s meta-data easily parsed as JSON objects. This feature creates a framework with wider compatibility and interoperability with external systems. The evaluation and operational behavior of the new module was tested through a set of data transfer experiments over a wide area network environment. These experiments were performed to ensure that the changes in the system’s architecture did not affected its performance.Givet det nuvarande läget för input/output (I/O) och lagringsenheter för system i peta-skala, skulle inkrementella lösningar bli ineffektiva om de implementerades i exa-skalamiljöer. Enligt ”The International Exascale Software Roadmap”, av Dongarra et al., är nuvarande I/O-arkitekturer inte tillräckligt skalbara, särskilt eftersom nuvarande delade filsystem har begränsningar när de används i storskaliga miljöer. Dessa begränsningar är: Bandbredd skalar inte på ett ekonomiskt sätt i storskaliga system, I/O-trafik på höghastighetsnätverk kan ha påverkan på och blir påverkad av andra orelaterade jobb, och I/O-trafik på lagringsservern kan ha påverkan på och bli påverkad av andra orelaterade jobb. Framtida applikationer på exa-skaladatorer kommer kräva I/O-bandbredd proportionellt till deras beräkningskapacitet. För att undvika dessa begränsningar föreslog C. Filippidis, C. Markou och Y. Cotronis ramverket IKAROS. I detta examensarbete utökas funktionaliteten hos den publikt tillgängliga modulen elastic-transfer (eT) som framtagits utifrån IKAROS. Den befintliga versionen av eT-ramverket implementerar Internet Message Access Protocol (IMAP) klient-serverkommunikation genom modulen ”Inbox” från Node Package Manager (NPM) ur Node.js programmeringsspråk. Denna modul användes som ett koncepttest, men i en verklig miljö så underminerar denna implementation systemets skalbarhet när ett stort antal värdar ansluter till systemet. Varje klient begär individuellt information relaterad till systemets metadata från IMAP-servern, vilket leder till en ineffektiv allokering av systemets resurser när ett stort antal värdar är samtidigt anslutna till eT-ramverket. Denna uppsats löser problemet genom att använda ett asynkront, icke-blockerande och händelsedrivet tillvägagångssätt för att implementera en IMAP klient-serveranslutning. Detta görs genom att integrera och modifiera NPM:s ”Imap”-modul, tagen från NPM:s katalog, så att den passar eT-ramverket. Eftersom formatet JavaScript Object Notation (JSON) har blivit ett av de mest spridda formaten för datautbyte så modifieras även eT:s metadata-struktur för att göra systemets metadata enkelt att omvandla till JSON-objekt. Denna funktionalitet ger ett bredare kompatibilitet och interoperabilitet med externa system. Utvärdering och tester av den nya modulens operationella beteende utfördes genom en serie dataöverföringsexperiment i en wide area network-miljö. Dessa experiment genomfördes för att få bekräftat att förändringarna i systemets arkitektur inte påverkade dess prestanda.
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Bodin-Deshayes, Claire. "Epitaxie par jets moléculaires d'hétérostructures CdTe-CdMnTe : application aux structures laser et structures piézoélectriques." Grenoble 1, 1993. http://www.theses.fr/1993GRE10139.
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Des heterostructures de semiconducteurs ii-vi en cdte-cdmnte sont elaborees par la technique d'epitaxie par jets moleculaires (ejm). Elles sont ensuite caracterisees et etudiees en vue d'applications. Les conditions de croissance des couches de cdmnte sont optimisees selon les deux directions cristallographiques <001> et <111>. Le desaccord de maille entre le puits cdte et les barrieres cdmnte limite les structures coherentes realisables. La composition de l'alliage cdmnte, ainsi que les epaisseurs des couches sont maitrisees. Des structures de bonne qualite structurale et optique ont ete obtenues, ce qui a permis d'etudier des structures laser et des structures piezoelectriques. Des laser visibles compacts pompes electroniquement ont ete realises. Le dispositif s'appelle laser a semiconducteur a micropointe (lsm). La zone active est constituee d'une heterostructure a confinement separe et a gradient d'indice lineaire (l. Grinsch) epitaxiee selon la direction <001>. La longueur d'onde d'emission laser atteinte avec cdmnte est dans le rouge a temperature ambiante. La croissance de puits quantiques selon l'axe polaire <111> est tres interessante: l'existence d'un grand champ piezoelectrique (de l'ordre de 100000 v/cm) a ete mis en evidence experimentalement. Ce champ modifie la structure electronique et les proprietes optiques de l'heterostructure. Lors de l'ecrantage du champ par des porteurs photocrees, la raie se decale vers le bleu, ce qui est prometteur pour les applications en optique non lineaire ou en electro-optique. Pour expliquer les resultats experimentaux, l'hypothese d'une non-linearite du coefficient piezoelectrique a ete emis
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Luttmann, Michel. "Ellipsométrie spectroscopique à angle variable : applications à l'étude des propriétés optiques de semi-conducteurs II-VI et à la caractérisation de couches à gradient d'indice." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10232.
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Ce travail apporte une contribution a la caracterisation des couches minces par ellipsomerie spectroscopique a angle variable. Nous presentons les differentes modifications apportees a l'ellipsometre d'origine et decrivons les procedures d'etalonnage utilisees. La reduction des erreurs systematiques et aleatoires est egalement traitee. Une etude originale a ete menee sur les derivees partielles des angles ellipsometriques psi et delta par rapport aux differents parametres de l'echantillon (epaisseurs, indices, angle d'incidence). Celle-ci nous a conduit a introduire le concept de sensibilite integrale relative (sir) qui s'est avere tres utile pour localiser les zones angulaires les plus interessantes et pour comparer entre elles les sensibilites de la mesure ellipsometrique aux divers parametres de l'echantillon. L'interet de mesures spectroscopiques a plusieurs angles d'incidence est discute. Deux applications principales ont ete traitees dans ce memoire: la premiere concerne la mesure des indices de semi-conducteurs ii-vi a grands gaps. L'etude realisee porte sur des substrats massifs de cdmnte et sur des couches epitaxiees de cdmgte. Une loi d'indice permettant de decrire le comportement de la fonction dielectrique du cdmgte sur l'ensemble du domaine spectral est proposee. Dans la zone transparente, deux lois de sellmeier donnant les indices du cdmnte et du cdmgte pour toute concentration de manganese ou de magnesium, ont ete etablies. La seconde porte sur la caracterisation de couches a gradient d'indice. Une methode permettant d'analyser des couches de profil d'indice a priori quelconque est proposee. Elle a ete validee sur des couches inhomogenes de gaalas et d'oxy-nitrure de silicium. L'ellipsometrie s'est revelee etre une technique bien adaptee a ce type de caracterisation puisque des profils polynomiaux du quatrieme degre ont pu etre mis en evidence sur des couches d'oxy-nitrure de silicium a fort gradient d'indice
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Kluzová, Ivana. "Návrh soustavy CZT a tepelných zdrojů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378717.
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Fujdiak, Radek. "Analýza a optimalizace datové komunikace pro telemetrické systémy v energetice." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-358408.
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Telemetry system, Optimisation, Sensoric networks, Smart Grid, Internet of Things, Sensors, Information security, Cryptography, Cryptography algorithms, Cryptosystem, Confidentiality, Integrity, Authentication, Data freshness, Non-Repudiation.
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Chiu, Chun-ming, and 邱俊銘. "Complementary electrochromic device using metal grid electrode structure." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/nmc68b.
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碩士國立中山大學
電機工程學系研究所
103
In this study, the electrodes for the complementary electrochromic device (CECD) were fabricated using cooper, nickel-vanadium and tungsten by pulsed-DC sputtering deposite on and formed the metal grid structure by self-made mask. Then, the electrochromic films of NiO and WO3 were respectively deposited on these electrodes by e-beam evaporation. Finally, these electrodes were applied to CECDs with gel polymer electrolyte. This study sequentially investigated the stability of high-temperature environment and electrochemical circulation, uniformity of the simulated electric field and the effect on the device characteristics with or without metal grid structure. The first part of the experimental results is the characteristics of the metal electrode. When the environment temperature rising to 100 ℃, the sheet resistances of the W, Ni-V and Cu were rised less than 5 %. For the stability of the electrochemical part, the CECD was fabricated with metal electrodes and switched 50 times with ± 1.8 V. The results reveal that the attenuation of the consumed charge of devices with Cu and Ni-V is 14 % and W is the lowest with 8 %. Consequently, the metal W exists the highest electrochemical stability. For the uniformity of the simulated electric field part, the uniformity of the electric field was enhanced by using metal grid structure and the more uniform electric field received by using Cu grid due to its excellent conductivity. For the fabrication and the analysis of CECD, the CECD exhibited better electrochromic characteristics when the applied voltage is 1.8 V. When the applied time of CECD is 60 s, the experiment results (λ@550 nm) show that the transmittance of colored state is 36.17 %, transmittance change (ΔT%) is 36.16 % and the coloration efficiency (η) is 77.92 cm2/C. The CECD using W grid electrode structure (W-CECD) exhibited better electrochromic characteristics when the applied time is 60 s. The experiment results (λ@550 nm) show that the transmittance of colored state is 32.46 %, ΔT% is 39.08 % and η is 81.93 cm2/C. The CECD using Cu grid electrode structure (Cu-CECD) exhibited better electrochromic characteristics when the applied time is 30 s. The experiment results (λ@550 nm) show that the transmittance of colored state is 36.73 %, ΔT% is 36.67 % and η is 29.62 cm2/C. For the response time and the memory effect, the response time of the CECD was found to be about 94 s and the transmittance of colored state increased to 36.35 % after 24 h without biased voltage supply. The response time of the W-CECD was found to be about 98 s and the transmittance of colored state increased to 33.31 % after 24 h without biased voltage supply. The results show that the memory effect was still excellent after using metal grid electrode structure.
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"Mobile agents for global mobile device grid infrastructure enterprises." Thesis, 2010. http://hdl.handle.net/10210/3261.
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M.Sc.Grid computing is a technology concerned with harvesting idle resources of geographically distributed and interconnected computers. It solves problems regarded as too complex or large to be solved by a single computer. Furthermore, economic grid computing is becoming the most dominant form of grid computing. It enables some form of payment to occur between resource producers and resource consumers in grid computing. Mobile devices and mobile telecommunication services, a relatively new field of technology, are rapidly increasing in popularity, size, strength and application. At the end of 2006, there were approximately 2.7 billion global active mobile users utilising mobile devices and mobile telecommunication services [Aho07]. At the end of 2007 this number had grown to 3.3 billion mobile users, more than half a billion additional mobile users in a period of one year [McN07]. With such large numbers, grid computing can benefit from the clustering of mobile devices forming a mobile grid computing model. However, there are many inherent disadvantages concerning mobile devices, such as low processing capabilities, unpredictable network connections and battery utilisation. Such hurdles must be addressed and solved if a mobile computing infrastructure or architecture is ever to be considered. This dissertation proposes the implementation of an economic mobile computing solution: Mobile Agents for Global Mobile Device Grid Infrastructure Enterprises, or MAGGIE. MAGGIE is concerned with harvesting idle mobile device resources by implementing the supply and demand economic model, aiming to create a healthy competitive economic market environment. MAGGIE implements agent and mobile agent technology to compensate for the hurdles introduced by mobile devices and mobile device software development platforms. It is targeted at both Sun Microsystems’s J2ME MIDP 2.0 and Microsoft’s .NET Compact Framework, enabling lower-end and higher-end mobile devices to contribute mobile computing services and resources for utilisation by other mobile device users. The primary goal of MAGGIE is to produce an architecture as generic as possible regarding the development and implementation of MAGGIE services. MAGGIE allows third-party application developers to seamlessly implement an array of MAGGIE services, without indepth prior knowledge of the architecture and technical aspects of MAGGIE. Finally, MAGGIE’s capabilities are demonstrated by implementing a distributed mobile chess service known as the MAGGIE Chess Service. The MAGGIE Chess Service enables a collection of distributed mobile devices in determining the best move originating from a chessboard position.
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"Robust Control of Wide Bandgap Power Electronics Device Enabled Smart Grid." Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.46215.
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abstract: In recent years, wide bandgap (WBG) devices enable power converters with higher power density and higher efficiency. On the other hand, smart grid technologies are getting mature due to new battery technology and computer technology. In the near future, the two technologies will form the next generation of smart grid enabled by WBG devices. This dissertation deals with two applications: silicon carbide (SiC) device used for medium voltage level interface (7.2 kV to 240 V) and gallium nitride (GaN) device used for low voltage level interface (240 V/120 V). A 20 kW solid state transformer (SST) is designed with 6 kHz switching frequency SiC rectifier. Then three robust control design methods are proposed for each of its smart grid operation modes. In grid connected mode, a new LCL filter design method is proposed considering grid voltage THD, grid current THD and current regulation loop robust stability with respect to the grid impedance change. In grid islanded mode, µ synthesis method combined with variable structure control is used to design a robust controller for grid voltage regulation. For grid emergency mode, multivariable controller designed using H infinity synthesis method is proposed for accurate power sharing. Controller-hardware-in-the-loop (CHIL) testbed considering 7-SST system is setup with Real Time Digital Simulator (RTDS). The real TMS320F28335 DSP and Spartan 6 FPGA control board is used to interface a switching model SST in RTDS. And the proposed control methods are tested. For low voltage level application, a 3.3 kW smart grid hardware is built with 3 GaN inverters. The inverters are designed with the GaN device characterized using the proposed multi-function double pulse tester. The inverter is controlled by onboard TMS320F28379D dual core DSP with 200 kHz sampling frequency. Each inverter is tested to process 2.2 kW power with overall efficiency of 96.5 % at room temperature. The smart grid monitor system and fault interrupt devices (FID) based on Arduino Mega2560 are built and tested. The smart grid cooperates with GaN inverters through CAN bus communication. At last, the three GaN inverters smart grid achieved the function of grid connected to islanded mode smooth transitionDissertation/Thesis
Doctoral Dissertation Electrical Engineering 2017
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Hong, Guan-Qun, and 洪冠群. "DC Power Storage Device and AC Grid-Connected Inverter Design for Wind Energy Systems." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/j28a93.
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碩士中原大學
電機工程研究所
99
Wind maximum power tracking with DC power storage and grid connected ability is developed separately in this thesis. In the first part, the DC power storage system regulates the unstable wind energy to a smoother power source in order to store the generated power into the battery stack. Moreover, the power generation is also maximized with a maximum power changer. Then, grid-connected inverter in the second part of this thesis, a current-controlled grid-connected inverter is designed to transfer the wind power energy to the AC utility grid. Furthermore, a maximum power algorithm is developed to increase the power transferred into the utility grid. Based on the current error between the utility-grid current and the maximum power reference current, a Proportional control circuit is used to synchronize and maximize the inverter current to the utility grid. Experimental performance and theoretical analysis are verified through a 400 watt wind turbine simulation platform. From the results, the DC power storage and grid connected systems are not only feasible but also show good results.
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Chen, Kuo-Hua, and 陳國華. "Multi-objective Optimization of Flip Chip Ball Grid Array Process Using Embedded Device Substrate." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/25970343355302412722.
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碩士國立高雄第一科技大學
機械與自動化工程所
98
SOC (system on chip) and SiP (system in package) are developed for more complex and highly integrated functions in Electronic products. Even though both of them have the common characteristic of significantly reducing the package size and improving the system effectiveness, they still have their own advantages and dis-advantages. In recent years, SOC technology significantly reduces the chip number for chipset, and SiP technology integrates assembly processes for the chipset and passive components. At the moment, the mainstream of the system process technology is still dominated by multi-chips module. The flip-chip packaging technology can reach 10 3 I/O count per square centimeter. However, under the multimode system operations trends, the system process technology has to integrate the electronic circuits and components with a variety of information and communication system standards. Therefore, the I/O density level will not be able to meet the demand by the present technology. The embedded SiP 3D packaging technology development began with active component deposited on the substrate surface and passive components embedded in the substrate. In the advanced SiP 3D technology, the active component is embedded into the substrate, which can significantly shorten the connection path between embedded passive components and active component to enhances RF performance。 The embedded SiP application is majorly for handheld communication equipment system IC. This experiment is related to embedded device substrate application in flip-chip packaging process, especially to the study of improving interface quality between chip and substrate. The problem solving is focusing on packaging materials reorganization with the conditions of flip chip thickness, underfill, solder resist at the production stage. The Taguchi and Principal Component Analysis with Fuzzy theory is used to improve flip-chip packaging quality problems such as open circuit, short circuit and delamination.
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Ferreira, João C. "Mobi-System: towards an information system to support sustainable mobility with electric vehicle integration." Doctoral thesis, 2013. http://hdl.handle.net/1822/28871.
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Tese de doutoramento do Programa Doutoral em Líderes para as Indústrias Tecnológicas (Programa MIT-Portugal - Área EDAM)The current Thesis proposes the conceptual aspects and the preliminary prototype of a mobile information system to support information integration and manipulation towards the Electric Vehicle (EV) introduction, and the support of mobility process in urban environments, giving recommendations to drivers about EV range autonomy, charging stations, electricity market, and also as route planner taking into account public transportation, car or bike sharing systems. The main work objective is the creation of an Information and Communication Technology (ICT) platform based on successful approaches developed in the Computer Science Area, recommender systems, cooperative systems and mobile devices, to help the driver of EV by giving real time information related with EV charging process, range autonomy, electricity market participation, and also smart mobility process in cities by giving guidance towards best route options, taking into account time travel and CO2 emissions. Based on the analysis of the problem a conceptual system and a prototype application were created under the designation “Mobi-System”, designed to mobile devices, with relevant information oriented to: (1) EV charging process; (2) EV range autonomy; (3) electricity market participation; and (4) mobility process in smart cities of the future. In this work it was developed an application to store data related with EV charging/discharging process, for further intelligent analysis and remote interaction with the charging system, determining a smart charging procedure, taking into account the distribution electrical system limitations, and the creation of communities with participation in the electricity market. A range estimation and representation process is introduced as part of the help process to assist EV drivers. An Aggregator system and a collaborative broker for distributed energy sources are proposed, taking into account the electricity market. A proposal for data integration of different transportation sources and a multimodal best route path are proposed based on CO2 emissions and time travel.
O presente trabalho consiste na concepção e discussão do sistema Mobi-System, que disponibiliza informação relevante para condutores de veículos elétricos (VE), tendo em conta os problemas dos carregamentos dos VE, a gestão da ansiedade de autonomia (range anxiety) dos condutores, a participação no mercado de energia elétrica, a integração das fontes de energia renováveis, bem como a integração de informação de transportes públicos e a criação de sistemas para gerir o problema da mobilidade sustentável em cidades inteligentes (smart cities). O objectivo principal do trabalho é o uso apropriado de Tecnologia da Informação e Comunicação (TIC) baseada em abordagens bem-sucedidas desenvolvidas na área da informática, como os sistemas de recomendação, sistemas cooperativos e dispositivos móveis para ajudar o condutor de VE, dando informações relevantes em tempo real, orientando o condutor para os pontos de carregamento públicos, ou para o melhor caminho tendo em conta o tempo e as políticas ambientais, nomeadamente as emissões de CO2. Com base na análise do problema, um sistema conceitual e uma aplicação protótipo foram criadas sob a designação de Mobi-System, projetada para dispositivos móveis com informações relevantes orientadas a: (1) processo de carregamento do VE feito num local público com a orientação e a reserva de slots de carregamento, ou em casa com a programação do processo de carregamento lento, tendo em conta limitações de potência; (2) gestão assistida da autonomia dos VE; (3) participação no mercado de energia, pela criação de comunidades de condutores com capacidade de participar no mercado de energia, dado o VE poder atuar como um armazenador de energia; e (4) processo de mobilidade em cidades inteligentes do futuro, com a proposta de integração de dados de diferentes tipos de transporte, com indicação do trajeto de melhor rota multimodal, proposto com base nas emissões de CO2 e no tempo das viagens.