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Engelke, Kylan Wynn. "Novel thermoelectric generator for stationary power waste heat recovery." Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/engelke/EngelkeK0510.pdf.
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Internal combustion engines produce much excess heat that is vented to the atmosphere through the exhaust fluid. Use of solid-state thermoelectric (TE) energy conversion technology is a promising technique to recapture some of the energy lost. The TE effect, discovered in 1821 by Thomas Seebeck, is essentially the solid-state conversion of a temperature gradient into an electric potential. The scope of this work was the design, testing and evaluation of a novel and robust TE generator that is amendable to use in a vast array of convective thermal processes. Seebeck testing of TE elements was combined with thermal/hydraulic and thermoelectric modeling to develop the design of a working prototype system. A proof-of-concept small-scale prototype (SSP) TE generator was built to evaluate concepts intended for the construction of a fully-functional field demonstration prototype (FDP). The SSP was used to evaluate electrical contact integrity, thermal characteristics, various TE materials and the feasibility of using compression-based TE contacts. The SSP featured 9 P/N TE pairs and has thus far produced a maximum open-circuit voltage of 380mV and a maximum electrical power of 1.47W. Knowledge gained from the SSP construction and testing was utilized in the design and fabrication of the FDP. A liquid-cooled Honda ES6500 6.0kW genset was procured to provide a test-bed for the FDP. The primary goal was to power the electric radiator fan with the heat energy contained in its exhaust, thus decreasing the genset's fuel consumption rate. The FDP contained 256 P/N pairs and thus far has produced an open-circuit voltage of 5.5VDC and a maximum power of 8.49W. Replacing the stock muffler reduced fuel consumption by 11.6% whereas removing the fan load reduced it an additional 1.64%. Through the recovery and conversion of wasted thermal energy, the genset's fuel consumption rate was successfully lowered, therefore validating the benefits of secondary TE power systems. The radiator fan of the Honda ES6500 consumes approximately 1% of the overall power output of the genset. Radiator fans in larger gensets can draw as much as 12-16% of their peak output. By recuperating waste heat, substantially higher fuel savings could be achieved.
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Erbes, Teodora. "Stochastic Learning Feedback Hybrid Automata for Dynamic Power Management in Embedded Systems." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9709.
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Dynamic Power Management (DPM) refers to the strategies employed at system level to reduce energy expenditure (i.e. to prolong battery life) in embedded systems. The trade-off involved in DPM techniques is between the reductions of energy consumption and latency incurred by the jobs to be executed by the system. Such trade-offs need to be decided at runtime making DPM an on-line problem. In this context, the contributions of this thesis are two-fold. Firstly, we formulate the DPM problem as a hybrid automaton control problem. We model a timed hybrid automaton to mathematically analyze various opportunities in optimizing energy in a given system model. Secondly, stochastic control is added to the automata model, whose control strategy is learnt dynamically using stochastic learning automata (SLA). Several linear and non-linear feedback algorithms are incorporated in the final Stochastic Learning Hybrid Automata (SLHA) model. Simulation-based experiments show the expediency of the feedback systems in stationary environments. Further experiments are conducted using real trace data to compare stochastic learning strategies to the outcomes of several former predictive algorithms. These reveal that SLHA attains better trade-offs than the other studied methods under certain trace data. Advanced characterization of trace sequences, which allows a better performance of SLHA, is a subject of further study.Master of Science
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Elwell, Lance Christopher. "Dynamics of stationary and obliquely oscillating free plane jets." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/17371.
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Gewald, Daniela [Verfasser]. "Waste heat recovery of stationary internal combustion engines for power generation / Daniela Gewald." München : Verlag Dr. Hut, 2013. http://d-nb.info/1045987735/34.
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PESENTI, GILCINEA RANGEL. "REMOTE MEASUREMENT AS STRATEGY TO MONITOR STATIONARY BATTERIES: CASE STUDY IN AN ELETRIC POWER SUBSTATION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=22108@1.
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A presente dissertação tem por objetivo geral validar em condições reais de operação, a técnica (desenvolvida em ambiente laboratorial) de monitoramento remoto de baterias estacionárias e como objetivos específicos identificar as limitações das tecnologias convencionais de monitoramento de baterias estacionárias, avaliar a confiabilidade do método de monitoramento remoto proposto e justificar a alternativa tecnológica proposta à luz do impacto econômico que dela decorrem. O desenvolvimento deste tema de dissertação de mestrado foi motivado pelas contribuições que poderá produzir para a Light e demais empresas dos setores elétricos, óleo e gás, bancário, de telecomunicações, entre outros setores que utilizam baterias estacionárias. A Light e o CPqD realizaram o projeto de PeD Light-Aneel 033/2008. Este projeto teve como objetivo o aumento da confiabilidade dos serviços auxiliares das subestações e redução dos custos de manutenção. Para tal efeito, foi desenvolvido um sistema automatizado de monitoramento e gestão individual e remota de todos os elementos que compõe o banco de baterias. A pesquisa de mestrado avaliou, quantitativamente, a confiabilidade da medição remota realizada na subestação Baependi da Light, na cidade do Rio de Janeiro. A metodologia aplicada na presente dissertação consiste em estudos estatísticos (Testes de hipóteses paramétricos e não paramétricos) para comparação de resultados de tensão elétrica e impedância obtidos em condições reais de operação (Medições SIMBA-GEBAT) em relação ao equipamento portátil de medição. A pesquisa validou aos níveis de significância de 90 por cento, 95 por cento e 99 por cento, a metodologia empregada para avaliação remota de baterias para os ensaios de impedância e tensão elétrica e identificou a repetitividade da metodologia da avaliação remota. O resultado da pesquisa foi fundamental para provar a credibilidade do sistema de monitoramento remoto de baterias. A utilização desse sistema ora validado contribuirá para o aumento da confiabilidade dos equipamentos que utilizam sistema de backup, além de redução dos custos de manutenção preventiva.The present work has the general objective of validating, under real operation conditions, the technique (developed in a laboratorial environment) of remote monitoring of stationery batteries. The development of this MsC dissertation theme was motivated by the contributions that it is expected to give to the Light S.E.S.A. and other companies of the Electric Sector, Oil and Gas, Bank, IT and many others which use stationary batteries in their DC energy supply. Light and CPqD developed together a Research and Development Project named ReD Light-ANEEL 033/2008. This project had as its main objective to increase the reliability of the ancillary services of substations and to reduce their maintenance costs. To reach this target, was developed an automated monitoring system and a remote individual management of all elements that form the batteries bank. The MSc research evaluated, quantitatively, the reliability of the remote metering, performed to the Light’s Baependi substation, which is located in the south zone of Rio de Janeiro City. The methodology applied in this dissertation consists of statistical studies (Hypothesis testing parametric and nonparametric), for comparison of voltage and impedance results obtained in actual operating conditions (Measurements SIMBA-GEBAT) compared to portable measurement. The research has validated, to the significance levels of 90 per cent, 95 per cent and 99 per cent, the methodology used to the remote evaluation of batteries relatively to the impedance and voltage essays, and has also identified the repetitivity of the remote evaluation methodology. The research results were fundamental to prove the credibility of the remote monitoring system of batteries. The use of this system will contribute to increase the reliability of the equipments which use backup systems, besides promoting a cost reduction of the predictive maintenance.
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Millis, Kathryn A. (Kathryn Ann). "Distributed measures of solution existence and its optimality in stationary electric power systems : scattering approach." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86430.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. [149]-151).
by Kathryn A. Millis.
Ph.D.
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Katayama, Masaaki. "Introduction to Robust, Reliable, and High-Speed Power-Line Communication Systems." IEICE, 2001. http://hdl.handle.net/2237/7222.
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Sham, Devin Krishna. "Analysis of exhaust waste heat recovery techniques from stationary power generation engines using organic rankine cycles." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-11072008-123311.
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Schendler, Phillip J. "Costs and benefits of using fuel cells for stationary power generation at Marine Corps Logistics Base Barstow Maintenance Center." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FSchendler.pdf.
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Thesis (M.S. in Management)--Naval Postgraduate School, December 2002.Thesis advisor(s): William R. Gates, David R. Henderson. Includes bibliographical references (p. 73-76). Also available online.
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Dreier, Sebastian. "The Impact of Films on the Long-Term Behavior of Stationary Electrical Connections and Contacts in Electric Power Systems." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-197959.
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Stationary electrical connections and contacts, such as power connections, are commonly applied in electric power systems used for generation, transmission and distribution of electric energy. Several different degradation mechanisms can increase the contact resistance and might therefore reduce the power connection’s lifetime. The degradation by film development as a result of chemical reactions is often considered as a reason for contact failure.
In this research work, the impact of film development produced by chemical reactions, such as oxidation, on the long-term behavior of stationary electrical connections and contacts was studied with crossed rods. Analytical, numerical and experimental methods were applied. Typical material systems for electric power systems were considered in this study: Cu-ETP (CW004A) bare, silver-, nickel- or tin-coated, Al99.5 (EN AW-1050A) and AlMgSi0.5 (EN AW-6060).
By applying numerical methods, the mechanical stress distribution was determined within a circular contact point. The initial contact resistance and the plastic deformed area of the considered material systems was measured in experimental tests. The film’s impact was further determined through comparative experimental studies in air (standard atmosphere) and N2 (inert gas).
During the experimental tests on perpendicularly crossed rods, other degradation mechanisms such as force reduction were suppressed. The film’s impact within the formation phase was studied on copper rods in an oven at 200 °C for 1000 h. Moreover, the dependency on different environments at 90 °C (laboratory, botanical garden and outdoor) was tested for 12000 h. Additional long-term tests over 12000 h were conducted at 200 °C. The contact resistance was determined dependent on time. Furthermore, the plastic deformed area was ascertained by microscopy. It was found that the time dependent film development caused by chemical reactions such as oxidation might possibly not result in a significant degradation of stationary electrical contacts with circular contact points and a constant force.
Supplementary studies were performed at 200 °C for 1000 h with perpendicularly crossed rods at low forces (3.5 N) as well as analytical assessment of radial and axial film growth on circular contact points. The measured long-term behavior of perpendicularly crossed rods was similar for low and high forces.
In order to study the long-term behavior of power connections operated in areas with harsh environmental conditions, experimental field tests on bolted busbar joints were conducted in desert and tropical rainforest environments. For over two and a half years, long-term field tests investigating bolted busbar joints made of Cu-ETP, Al99.5 (EN-AW-1350A) or AlMgSi0.5 (EN AW-6060) either with or without coating (silver, tin or nickel) were conducted in Belém (Brazil), Ismailia (Egypt) and Dresden (Germany).
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Chacón, Lisa, Benjamin Hornblow, Daniel Johnson, and Chris Walker. "Strategic Sustainable Development for the Stationary Power Sector : Is Carbon Capture and Storage a Strategic Investment for the Future?" Thesis, Blekinge Tekniska Högskola, Avdelningen för maskinteknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2382.
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An examination of the stationary power sector is performed using The Natural Step framework and Sustainability Principles (SP), in order to aid decision makers in developing policy to balance energy needs while reducing carbon dioxide (CO2) emissions in order to address climate change. Carbon capture and storage (CCS) is evaluated for its sustainability aspects, and is found to be a potentially sustainable approach which can be a bridging technology to a more sustainable energy mix, as well as a remediation technology which can remove CO2 from the atmosphere when utilized in combination with biomass fuel. Initial actions for restructuring the stationary power sector should emphasise demand reduction and efficiency efforts, followed by switching to renewable energy sources. If the first two strategies can not provide sufficient CO2 reductions, then investments in CCS technology may be an appropriate choice. CCS with coal-fired power can be a means to decouple CO2 emissions from fossil fuel use, but other SP violations associated with coal use must also be fully addressed before this strategy can be considered a truly sustainable option.
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Liu, Jie. "Failure prognostics by support vector regression of time series data under stationary/nonstationary environmental and operational conditions." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2015. http://www.theses.fr/2015ECAP0019/document.
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Ce travail de thèse est motivée par la possibilité de surveiller l'état des composants de systèmes d'énergie pour leur utilisation prolongée et sécuritaire, conformément à la pratique correcte de fonctionnement et des politiques adéquates de maintenance. La motivation est de développer des méthodes basées sur la régression à vecteurs de support pour la prédiction de données de séries chronologiques dans des conditions environnementales et opérationnelles stationnaire/ non-stationnaire. Les simples modèles et les ensembles de modèles à base de SVR sont développés pour attaquer la prédiction basée sur des petits et des grands ensembles de données. Des stratégies sont proposées pour la mise à jour de façon adaptative les simples modèles et les ensembles de modèles à base de SVR au cas du changement de la distribution générant les données. Les comparaisons avec d'autres méthodes d'apprentissage en ligne sont fournies en référence à des données de séries chronologiques d'un composant critique dans les centrales nucléaires fournis par Electricité de France (EDF). Les résultats montrent que les approches proposées permettent d'atteindre des résultats de prédiction comparables compte tenu de l'erreur quadratique moyenne et erreur relative, en beaucoup moins de temps de calcul. Par ailleurs, en analysant le sens géométrique de la méthode de la sélection de vecteurs caractéristiques(FVS) proposé dans la littérature, une nouvelle méthode géométriquement interprétable, nommé Reduced RankKernel Ridge Regression-II (RRKRR-II), est proposée pour décrire les relations linéaires entre un valeur prédite et les valeurs prédites des vecteurs caractéristiques sélectionné par FVS. Les comparaisons avec plusieurs méthodes sur un certain nombre de données publics prouvent la bonne précision de la prédiction et le réglage facile des hyperparamètres de RRKRR-IIThis Ph. D. work is motivated by the possibility of monitoring the conditions of components of energy systems for their extended and safe use, under proper practice of operation and adequate policies of maintenance. The aim is to develop a Support Vector Regression (SVR)-based framework for predicting time series data under stationary/nonstationary environmental and operational conditions. Single SVR and SVR-based ensemble approaches are developed to tackle the prediction problem based on both small and large datasets. Strategies are proposed for adaptively updating the single SVR and SVR-based ensemble models in the existence of pattern drifts. Comparisons with other online learning approaches for kernel-based modelling are provided with reference to time series data from a critical component in Nuclear Power Plants (NPPs) provided by Electricité de France (EDF). The results show that the proposed approaches achieve comparable prediction results, considering the Mean Squared Error (MSE) and Mean Relative Error (MRE), in much less computation time. Furthermore, by analyzing the geometrical meaning of the Feature Vector Selection (FVS) method proposed in the literature, a novel geometrically interpretable kernel method, named Reduced Rank Kernel Ridge Regression-II (RRKRR-II), is proposed to describe the linear relations between a predicted value and the predicted values of the Feature Vectors (FVs) selected by FVS. Comparisons with several kernel methods on a number of public datasets prove the good prediction accuracy and the easy-of-tuning of the hyperparameters of RRKRR-II
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Wei, Wei. "Underwater measurement of the sound-intensity vector : its use in locating sound sources, and in measuring the sound power of stationary and moving sources /." Full text available from ProQuest UM Digital Dissertations, 1994. http://0-proquest.umi.com.umiss.lib.olemiss.edu/pqdweb?index=0&did=1296083321&SrchMode=1&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1268675088&clientId=22256.
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Thesis (Ph.D.)--University of Mississippi, 1994.Typescript. "May 1994 ." Dissertation director: Dr. Robert Hickling Committee chair: Dr. Richard Raspet Includes bibliographical references (leaves 115-118). Also available online via ProQuest to authorized users.
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Brodén, Daniel. "Analysis of Demand Response Solutions for Congestion Management in Distribution Networks." Thesis, KTH, Industriella informations- och styrsystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-138575.
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According to the 20-20-20 targets set by the European Union, 50 percent of the Swedish electricity share is to be provided by renewable energy sources by 2020. The Smart Grid Gotland (SGG) project has emerged as a response to this target. The project aims at demonstrating a proof of concept on how smart grid solutions can be used to integrate large quantities of renewable energy sources in an existing network. The outcomes of the project are intended to pave the way for future renewable energy integration projects in Sweden. The Thesis focuses on one of the technical objectives of the SGG project, i.e. to increase the hosting capacity of wind power on Gotland from 195 MW to 200 MW by using Demand-Response (DR) from households and industries. DR consist of shifting peak-loads to peakproduction hours. The integration of additional wind power causes a risk of exceeding the transmission capacity of the power export cable between Gotland and the Swedish mainland. The approach considered for this Thesis is to use an Ancillary Service (AS) toolbox scheme based on multi-agent systems. The AS toolbox consist of flexibility tools such as DR on long-term, short-term, a battery energy storage system and a wind curtailment scheme. The DR activity includes space heating and domestic hot water consumption from detached houses on Gotland. The simulation results indicate that 1900 household participants are sufficient to balance the additional 5 MW for worst case scenarios. Furthermore, it is shown that the DR participation from industries contributes in some cases to a reduction of 700 household participants. The findings helped conclude that using an AS toolbox solution on Gotland is fully possible from a technical perspective. However, barriers that stand against its realisation are of economical nature and need to be investigated in future studies.
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Cetinkaya, Suleyman. "Repetitive Control Of A Three-phase Uninterruptible Power Supply With Isolation Transformer." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608150/index.pdf.
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A repetitive control method for output voltage control of a three phase uninterruptible power supply (UPS) with isolation transformer is investigated. In the method voltage control loop is employed in the stationary dq frame. The controller eliminates the periodic errors on the output voltages due to inverter voltage nonlinearity and load disturbances. The controller design and implementation details are given. The controller is implemented on a 5-kVA UPS prototype which is
constructed in laboratory. Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered. The steady-state and dynamic performance of the control method are investigated in detail. The theory of the control strategy is verified by means of simulations and experiments.
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Demirkutlu, Eyyup. "Output Voltage Control Of A Four-leg Inverter Based Three-phase Ups By Means Of Stationary Frame Resonant Filter Banks." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608151/index.pdf.
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A method for high performance output voltage control of a four-leg inverter based three-phase transformerless UPS is proposed. Voltage control loop is employed and the method employs stationary frame resonant filter controllers for the fundamental and harmonic frequency components. A capacitor current feedback loop provides active damping and enhances the output voltage dynamic performance. The
controller design and implementation details are given. Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered. The steadystate
and dynamic performance of the UPS are investigated in detail. A scalar PWM method with implementation simplicity and high performance is proposed and implemented. The control and PWM methods are proven by means of theory,
simulations, and experiments.
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Dreier, Sebastian [Verfasser], Steffen [Akademischer Betreuer] Großmann, Jemaa Noureddine [Akademischer Betreuer] Ben, and Konstantin [Akademischer Betreuer] Papailiou. "The Impact of Films on the Long-Term Behavior of Stationary Electrical Connections and Contacts in Electric Power Systems / Sebastian Dreier. Betreuer: Steffen Großmann. Gutachter: Steffen Großmann ; Noureddine Ben Jemaa ; Konstantin Papailiou." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://d-nb.info/1088185908/34.
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Lévêque, Hubert. "Synthèse d'oxazolines fonctionnelles chirales : accès aux phases stationnaires polymériques et greffage sur silice pour l'application à la chromatographie énantiosélective." Rouen, 1994. http://www.theses.fr/1994ROUES058.
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La synthèse de dérivés de l'oxazoline de Meyers à partir du (1S, 2S)-2-amino-1-phénylpropan-1,3-diol, a permis de préparer des phases stationnaires chirales pour évaluer le potentiel de ces hétérocycles en chromatographie énantiosélective. L'accès à des systèmes séparatifs, dont les performances ont été jugées satisfaisantes (séparation de dérivés d'aminoacides et d'amines aromatiques), a été effectué par introduction du motif chiral dans une chaîne polysiloxane ou par greffage sur silice. La mise au point de voies d'accès-sélectives à des oxazolines fonctionnelles chiales, isomères des précédentes, et à des fonctions amides dérivées d'amino ou cyano-oxazolines, a permis de disposer de plusieurs structures chirales dans cette série. Une étude, réalisée sur le greffage d'oxazolines fonctionnelles par des méthodes classiques (silanisation), nous a fourni des silices greffées à différents taux (de 0,36 a 1,06 mmol/g). D'autre part, le greffage d'une oxazoline chirale par un lien silicium-carbone a conduit à une phase stationnaire énantiosélective
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Barden, Alisson Thomas. "Projeto e análise de controladores robustos aplicados a inversores trifásicos de fontes ininterruptas de energia (UPS)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/141945.
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O objetivo principal deste trabalho é o desenvolvimento de controladores robustos baseados no princípio do modelo interno, em referenciais síncrono e estacionário, para aplicação ao estágio de saída de uma fonte ininterrupta de energia (UPS) a fim de minimizar a distorção na tensão de saída causada pela conexão de cargas não lineares balanceadas e desbalanceadas. A formulação em referencial estacionário (abc) é realizada através da aplicação de controladores com múltiplos modos ressonantes, a fim de se estabelecer erro nulo ao seguimento de referência senoidal e rejeição de distúrbios na tensão de saída devido às correntes com elevado conteúdo harmônico drenadas pelas cargas. Além disso, o controle é formulado em referencial síncrono (dq0) utilizando controladores Proporcional-Integral (PI) convencionais muito difundidos na maioria das aplicações comerciais de UPS. O projeto de ambos controladores é realizado utilizando uma metodologia de controle robusto com realimentação de estados, onde os parâmetros dos controladores são determinados através da resolução de um problema de otimização convexa sujeito a um conjunto de restrições na forma de desigualdades matriciais lineares (LMI). Uma análise comparativa de desempenho é realizada entre controladores com um modo ressonante (sintonizado na fundamental) e o PI em dq0, pois apresentam estruturas funcionalmente equivalentes sob a ótica do princípio do modelo interno aplicada a seus respectivos referenciais. Além do mais, demonstra-se a melhoria no desempenho com o uso dos controladores múltiplo ressonantes em referencial estacionário onde escolhe-se as frequências de ressonância de cada modo de maneira a suprimir os efeitos de harmônicas específicas na tensão de saída da UPS. A análise comparativa entre os controladores propostos é realizada através de simulações numéricas, utilizando os procedimentos de ensaio dinâmico e estático e as exigências estabelecidas pela norma internacional IEC 62040-3.The main objective of this work is the development of robust controllers based on the internalmodel principle, in synchronous and stationary frames, applied to the output stage of an uninterruptible power supply (UPS), in order to minimize the output voltage distortion caused by the connection of balanced and unbalanced nonlinear loads. The formulation in stationary abc-frame is accomplished through the aplication of a multiple resonant controller, so that, it is possible to achieve zero-error tracking of the sinusoidal reference and disturbances rejection on the output voltage due to the high amount of harmonic currents drained by the loads. Moreover, a controller in synchronous reference frame (dq0 axis) is formulated through the application of conventional Proportional-Integral (PI) controllers which are widely used in comercial UPS applications. The design of both controllers is formulated using a state-feedback robust controlmethod, in which the controller parameters are determined by solving a convex optimization problem subject to a set of LMI constraints. A comparative analysis on the performance of the single-mode resonant controller (tuned at the fundamental frequency) and the PI controller is performed, because these controllers are functionally equivalent in the sense of the internal model principle applied to their respective frames. Furthermore, the improvement in performance is demostrated with the use of multiple resonant controllers in stationary abc-frame where the resonance frequencies are chosen to suppress the effects of a specific harmonic in the UPS output voltage. The comparative analysis of the proposed controllers is performed through numerical simulations, making use of the dynamical and steady-state test methods and performance requirements defined by the IEC 62040-3 international stardard.
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Nilsson, Daniel, and Sebastian Berg. "Standardisering och modularisering av lågspänningsställverken i ABB:s HVDC-stationer." Thesis, University West, Division of Electrical and Automation Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-2588.
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Den här rapporten undersöker möjligheterna att standardisera och modulariseralågspänningsställverken i ABB:s HVDC-stationer. Anläggningarna har idag heltkundanpassade lösningar, vilket tar för lång tid att projektera för att kunna svara mot denökade efterfrågan på HVDC-lösningar.Arbetet baseras på tretton stationer i åtta pågående och avslutade projekt. Dessa skiljer sigtill storlek, lokalisering, ålder, dokumentation och stationstyp.För att kunna erhålla en korrekt men samtidigt överskådlig bild överlågspäninngsställverkets laster, granskades varje stations dokumentation. Informationensammanställdes i en databas, som visade de belastningar som var ständigt återkommande.Arbetet visar att det är möjligt att standardisera valda delar av lågspänningsställverken, docktas ingen hänsyn till vare sig storleks- eller kostnadsökning. Arbetet behandlar de mestfrekvent förekommande brytarstorlekarna för de typiska lasterna.Det standardförslag som tagits fram har anpassats för att täcka de brytarstorlekar somförekommit för de typiska lasterna i stationerna. För strömriktartransformatorerna erbjudstvå varianter av skåp, medan det för övriga laster endast förekommer ett alternativ.En alternativ lösning på problemet skulle kunna vara att ta fram en standard för varjestationstyp. Detta förutsätter dock ett större antal projekt av varje typ än de som tagits medi detta arbete.
This thesis investigates the possibilities to standardize and modularize the low-voltageswitchgear in ABB’s HVDC-stations. The reason for this is that the customized solutionthey use today take too much engineering and production time to meet the expectedincrease of projects.The report is based on thirteen stations in eight different closed or ongoing projects. Theselection was based on the station size, geographical location, commissioning year andstation type.In order to obtain a correct representation of the loads in the low-voltage switchgear, therelevant station documentation was reviewed and compiled in a database. The data wasthen analyzed to determine the most frequently occurring loads and their characteristics.The thesis shows that it’s possible to standardize some components in the low-voltageswitchgear. However, this report doesn’t take into consideration any possible increase oftotal size and cost. It also shows the most frequent sizes of the circuit breakers for each ofthe common loads.The standard proposition for the common loads was developed to cover all the occurringsizes of the circuit breakers in the stations. For the converter transformers coolingequipment there’s two different cubicles to choose from, while the remaining loads islimited to a single alternative.An alternative solution could be to develop a standard for each occurring station type.However, this would require that the data from a larger number of projects, for all stationtypes, are reviewed and compiled.
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Coelho, Afonso Salgado Porto. "Purcharsing power parity theory in the context of the euro currency." Master's thesis, Instituto Superior de Economia e Gestão, 2017. http://hdl.handle.net/10400.5/15228.
Full textAbstract:
Mestrado em Mathematical FinanceO foco desta tese é na teoria da paridade do poder de compra (PPC) no contexto do Euro entre 1999 até 2016. Esta teoria tem em vista a ligação entre as taxas de câmbio, juro e inflação. Assim, pretende-se saber se com a eliminação da taxa de câmbio, a teoria de PPC é consistente com a ligação entre taxa de juro e taxa de inflação para os países da Zona Euro. Para este estudo a amostra contém doze países com informações entre 1999 até 2016. Os países presentes na amostra são: Austria, Bélgica, Finlândia, França, Alemanha, Grécia, Irelanda, Itália, Luxemburgo, Holanda, Portugal e Espanha. Verifica-se que apesar de apesar de não haver grandes oscilações num periodo inicial à entrada da moeda única, a taxa de juro e a taxa de inflação sofreram posteriormente uma variação considerável entre os países da amostra. Estas observações podem questionar assim a validade da teoria do PPC no contexto do Euro.
This thesis focuses on the purchasing power parity (PPP) theory in the context of the euro from 1999 to 2016. PPP suggests a specific association between exchange, inflation and interest rates. The euro has eliminated exchange rates among participating countries. We inquire whether the elimination of the exchange rate could be reflected, similar to the inflation and interest rates of euro-area countries, consistent with PPP. The study has followed a panel of twelve countries from the introduction of the euro in 1999 until 2016. These countries are Austria, Belgium, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, Portugal and Spain. The findings show that after an initial period of similarity, and despite the elimination of exchange rates among these countries, inflation and especially country-level interest rates have exhibited a great degree of divergence. Therefore, these results may question the validity of the relationships PPP predicts in the context of the euro. Although the exchange rate between these countries remained the same, inflation and interest rates did not.
info:eu-repo/semantics/publishedVersion
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Pettersson, Martin. "Analyser av två VSC-HVDC-stationer genom långtidsmätningar med elkvalitetsmätare." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70056.
Full textAbstract:
Gotland har länge präglats av mycket speciella lösningar och legat i framkant vad gäller ny teknik. Under ca 20 år har Gotland haft en VSC-HVDC-station som har stabiliserat spänningen i det gotländska nätet. HVDC Light har löst en del av de tekniska begränsningarna som hindrat utvecklingen av vindkraftverk. Anläggningen börjar lida mot slutet av sin tekniska livslängd och examensarbetet är ett första steg i utredningen för en eventuell ersättning. Med hjälp av elkvalitetsmätare kartlagdes prestanda och eventuella förbättringsområden. Den svenska stamnätsoperatören Svenska kraftnät har sedan 2016 haft en VSC-HVDC-station som använts för att utväxla energi till asynkrona systemet i Östeuropa. Svenska kraftnät har på senare tid velat utnyttja spänningsregleringsmöjligheterna och utreda mättekniska metoder. Elkvalitetsmätare placerades ut på lämpliga mätpunkter för att utreda anläggningens beteenden. ELSPEC G4500 elkvalitetsmätare installerades på Nordbalt och Gotlands HVDC Light för att mäta under sensommar till hösten 2017. Skillnader mellan CVT och IVT samt Rogowskispole och CT mättes. Valet av ELSPEC lämpade sig bra eftersom att inga triggningsvillkor behövdes som tillåter att man kan upptäcka små men viktiga avvikelser. Gotlands HVDC Light stabiliserar nätet främst mot spänningsdippar efter kortslutningar i 10 kV-elnätet och flimmer ifrån vindkraftsparkerna i ände 2. Märkeffekten för en uppdaterad anläggning kommer baseras på den kortslutningseffekt i 10 kV-nätet som kan utvecklas under anläggningens livstid. Spänningsregleringen ska baseras på en PI-regulator och ska kunna reglera fullt på 40 ms. Komponentspänningar kan användas för att ge reaktiv effekt på de faser som behöver det. Behovet mot flimmer ska baseras på en mätning i närmaste konsumtionscentrum, två mil från ände 2. Om behovet finns, ska en separat loop för flimmerkontroll som motverkar 1,5 Hz-komponenter implementeras utifrån en punkt ca 1,5 mil ifrån ände 2. Teknikvalet står mellan two-level generation 3 eller MMC, beroende på uppgradering eller ersättning. Många olika framtida scenarion påverkar HVDC Lights roll och oavsett, kommer mycket resurser behövas för Gotlands och HVDC Lights framtid. Det har observerats två beteenden på Nordbalt varav ena är långsam och det andra beteendet är snabbt. Det snabba beteendet uppstår när lågohmiga fel sker som också synkronmaskinerna tar hand om. Nordbalt kan hjälpa till för mindre spänningsvariationer om den varit snabbare likt beteendet vid lågohmiga fel. En stabilitetsbedömning behövs dock eftersom att snabbare beteende ökar risken för instabilitet. Eftersom att data mellan CVT och IVT skiljde sig mycket, upplystes mättekniska problem. Några lösningar diskuteras varav RCVT och PQSensor gås igenom grundligt. Alternativa lösningar som MoW och mobila enheter presenteras också vagt. Samtliga lösningar visade sig ha praktiska hinder, vilket försvårar genomförandet. Det uppmanas därför att man bör testa teknikerna i laborationsmiljö eftersom begränsat med studier gjorts på dessa samt att konkurrerande tillverkare uppger olika uppgifter.Gotland has long been known for various special solutions and been on the leading edge regarding new technology. For the past 20 years Gotland has had a VSC-HVDC station that has stabilized the voltage in the Gotlandic grid. HVDC Light has solved some of the technical limitations that has hindered the growth of wind turbines. The station has almost reached the end of its technical lifespan and the thesis is a first step in the investigation for an eventual replacement. With power quality analyzers performance and improvements were investigated. The Swedish transmission system operator Svenska kraftnät have since 2016 had a VSCHVDC station that have been used to exchange energy to the asynchronous system in Eastern Europe. Svenska kraftnät has of lately wanted to take advantage of the voltage control capabilities and investigate measurement technologies. Power quality analyzers were installed on suitable connection points to investigate the behavior of the station. ELSPEC G4500 power quality analyzers were installed on Nordbalt’s and Gotland’s HVDC Light to measure during the late summer to fall of 2017. The differences between CVT and IVT, and Rogowski coil and CT were captured. The choice of ELSPEC suited well since no trigger conditions are needed which allows small but important errors to be discovered. Gotland’s HVDC Light stabilizes the grid mostly against voltage sags for faults in the 10 kVgrid and flicker from the wind farms in node 2. The rated power for an upgrade should be based on the 10 kV-grid short-circuit power to be developed during the station’s life span. The voltage control should be based on a PI-controller and should be able to transmit full power in 40 ms. Component voltages can be used to produce reactive power on the phases in need. The need against flicker should be based on measurements in the closest center of consumption, 2 miles from node 2. If it’s needed, a separate loop for flicker-control that prevents 1.5 Hz-components based on a point 1.5 mile from node 2 should be implemented. Depending on an upgrade or replacement, the topology can either be “two-level generation 3” or MMC. Many different future scenarios affect HVDC Light’s role and more resources will be required for Gotland’s and HVDC Light’s future. Two behaviors have been observed on Nordbalt where one is slow and the other behavior is fast. The fast behavior was only observed when low impedance faults occurs, that the synchronous generators also handles. Nordbalt can contribute to small voltage variations if it was faster, like the behavior for low impedance faults. A consideration in stability is needed since a faster behavior can lead to stability problems. Since the data between CVT and IVT differed a lot, metrology problems were discovered. Some solutions were discussed, of which RCVT and PQSensor was thoroughly reviewed. Alternative solutions like MoW and mobile units were also presented vaguely. All solutions showed practical difficulties, which complicates the implementation. It is therefore encouraged to test the technologies in a laboratory environment since few studies have been made on these and competing manufactures state different information.
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Van, Heerden Petrus Marthinus Stephanus. "The relationship between the forward– and the realized spot exchange rate in South Africa / Petrus Marthinus Stephanus van Heerden." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4511.
Full textAbstract:
The inability to effectively hedge against unfavourable exchange rate movements, using the
current forward exchange rate as the only guideline, is a key inhibiting factor of international
trade. Market participants use the current forward exchange rate quoted in the market to make
decisions regarding future exchange rate changes. However, the current forward exchange rate
is not solely determined by the interaction of demand and supply, but is also a mechanistic
estimation, which is based on the current spot exchange rate and the carry cost of the
transaction. Results of various studies, including this study, demonstrated that the current
forward exchange rate differs substantially from the realized future spot exchange rate. This
phenomenon is known as the exchange rate puzzle.
This study contributes to the dynamics of modelling exchange rate theories by developing an
exchange rate model that has the ability to explain the realized future spot exchange rate and
the exchange rate puzzle. The exchange rate model is based only on current (time t) economic
fundamentals and includes an alternative approach of incorporating the impact of the interaction
of two international financial markets into the model. This study derived a unique exchange rate
model, which proves that the exchange rate puzzle is a pseudo problem. The pseudo problem
is based on the generally excepted fallacy that current non–stationary, level time series data
cannot be used to model exchange rate theories, because of the incorrect assumption that all
the available econometric methods yield statistically insignificant results due to spurious
regressions. Empirical evidence conclusively shows that using non–stationary, level time series
data of current economic fundamentals can statistically significantly explain the realized future
spot exchange rate and, therefore, that the exchange rate puzzle can be solved.
This model will give market participants in the foreign exchange market a better indication of
expected future exchange rates, which will considerably reduce the dependence on the
mechanistically derived forward points. The newly derived exchange rate model will also have an influence on the demand and supply of forward exchange, resulting in forward points that are
a more accurate prediction of the realized future exchange rate.Thesis (Ph.D. (Risk management))--North-West University, Potchefstroom Campus, 2011.
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Wang, chun shu, and 王淳書. "Assessment Fuel Cell Technologies for Stationary Power Generation." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/69456441590039146953.
Full textAbstract:
碩士長庚大學
電子工程研究所
96
Recently, current generating plant costs from 9000-NT$14000/KL rise Boiler steam generated by 200-NT$300/Per ton climbed to 800-NT$900, Resulting in the use of heavy oil generator power greatly increased costs, couples with the Kyoto Protocal has come into force on the feb.16, 2005. After all, the use of a fuel cell power generation be an excellent way. In this thesis, was to assessment fuel cell technologies for stationary power generation.The temperature for SOFC can up to 600 -1000 ℃, used in the factory thermal coal temperature is 350 ℃. It can be reduce factory for the use of steam and thermal coal cost. PAFC maximum temperature reached 200 ℃. The PAFC can only reduce the cost of the factory for the use of steam. The results from analysis when the initial purchase cost of SOFC is US$1600-US$3200/KW have commercial value.When the initial purchase cost of PAFC is US$400 have commercial value. Key Words: Solid oxide fuel cell, SOFC; phosphoric acid fuel cells, PAFC; Heavy Oil Generator; Genetic algoriyhm
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Hung, L. C., and 洪龍成. "Short-term Non-Stationary Power Signal Prediction and Analysis." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/08798320195107377170.
Full textAbstract:
碩士義守大學
電機工程學系
87
Load forecasting is an important function in electric power system operation and management. A well load management can save a lot of cost for power utilities. Therefore, how to make an accurate load forecastingbecomes a necessary work in per-at ion of load management. In recent years, several forecasting methods have been proposed. One of these methods is neural network technique. It has been widely used in this field since its powerful learning capability. In real world, many forecasting problems can not solved by a fixed tool due to the particularity of the signal processing. In general, it is needed to develop a prediction model through a complex analysis step based on the historical data. However, power loads have strong periodic characteristics, which can be predicted by classifying short-term load forecasting (including hourly, daily, and weekly loads forecasting), mid-term load forecasting (including monthly and seasonally loads fore-casting) and long-term load forecasting (including yearly load forecasting). The prediction model tries to characterize the relationships between power load and its influence factors, including season, weather, temperature, humidity, time, holiday, human behavior of consumption, and so on. Such a characterized model then can be used as a forecasting tool in load system operation. In this thesis, two modules of neural network are studied and analyzed. One is neural network with stochastic back- propagation learning algorithm, the other one is neural network with traditional back-propagation learning algorithm. Taipower load data from 1992 to 1996, six years data are utilized for experimentation. Three types for load forecasting are investigated, i.e., one-hour-ahead load forecasting, one-day-ahead load forecasting and one-week-ahead load forecasting. The simulation results by each module are then compared. The advantage of distinct forecasting module is also analyzed and discussed.
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Kuo, Po-Chen, and 郭柏辰. "Control and Power Management of a Stationary Fuel Cell Hybrid System." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/12489187572216487682.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
100
This thesis proposes robust control and power management strategy for a 6kW stationary fuel cell hybrid power system to improve system stability and efficiency and to reduce fuel consumptions. The thesis deals with a 6kW stationary hybrid fuel cell system that was developed by a Taiwanese company M-Field. The 6kW system consist of two PEMFC modules, batteries and electrical components to form a parallel hybrid power system. The system was designed for telecom base stations to provide uninterruptible power during emergency power failures. First, the batteries were charged before the main power was shut down. In case of grid power failures, the batteries will start-up the balance-of-plant (BOP) of the PEMFC modules. Then power is continuously provided by the parallel hybrid power system. At low current load, the PEMFC modules provide steady power for the base station. At high current load, both the PEMFC modules and batteries provide electricity to the base station. we apply robust control and power management techniques to improve the stability and efficinency of the stationary system. The study was carried out by four steps: First, we apply robust control to the PEMFC modules to improve the system’s performance. Second, we replace the original lead-acid batteries with lithium-iron batteries, and compare their performance and efficiency. Third, we analyse the efficiency of the electrical components to estimate total energy loss. Lastly, we integrate the stationary fuel cell hybrid power system and verify system performance by experiments. Based on the results, the proposed robust control and power management are deemed effective in improving system stability and performance.
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Fan, Chun-Chih, and 范均誌. "Self-Tuning Policy for Dynamic Power Management on Non-Stationary Service Requests." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/85394943176149648885.
Full textAbstract:
碩士國立成功大學
資訊工程學系碩博士班
93
Energy consumption is an important system design issue. Dynamic Power Management (DPM) has been a key technique to save energy. The DPM is a design methodology to reduce power consumption of electric system by reconfiguring their power and performance level. However, for a large class of application in electric system likes PDAs and laptops, the workload for the system strongly depends on applications running and user operation on the system, which is very common in real-life systems. Hence, the workload is unknown at design time. To satisfy this condition, DPM schemes must deal with unknown and nonstationary stochastic environment. In this work, we present an on-line self-tuning DPM policy, which modeled as Markov Chains, to handle the nonstationary workload. Conventional DPM performs selective shutdown of idle system components. We extend DPM to manage multiple active power states of system component. We introduce a workload self-tuning technique based on sliding window, which dynamically adjust policy decision of DPM to meet the variations of environment. We simulate hardware characteristics of a processor to demonstrate the effectiveness of our approach.
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YANG, CHIEH-YU, and 楊傑宇. "Purchasing Power Parity in 5 BRICS-Stationary Test with a Nonlinear Fourier Function." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/90785846044022470637.
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Cheng, Ruei-mu, and 鄭瑞木. "The Purchasing Power Parity of Taiwan’s Main Trade Countries: Stationary Test with a Nonlinear Fourier Function." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/94411957181862345601.
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Lee, Chia-Hao, and 李家豪. "New Evidence from a Panel Stationary test with Structural Breaks on Purchasing Power Parity of East Asia." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/59407821077010331642.
Full textAbstract:
碩士逢甲大學
經濟學所
94
In this paper, we use the newly-developed and refined panel stationary test with structural breaks, as advanced by Carrion-i-Silvestre(2005), to examine long-run purchasing power parity(PPP) for US dollar real exchange rates of East Asian 10 countries during 1987-2005 period. The empirical results from numerous earlier panel-based unit root tests which do not take structural breaks into account indicate that purchasing power parity for all the countries we study here are non-stationary. When we employ Carrion-i-Silvestre(2005) panel stationary test with structural breaks, we find that real exchange rates of 7 East Asian countries have three structural breaks and other countries have two structural breaks. Moreover, the real exchange rates of East Asian 10 countries are still exhibits a non-stationary process. In other words, evidence shows that the long-run purchasing power parity for East Asian 10 countries does not hold even if structural breaks are taken into consideration.
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Zheng, Qinghe. "Catalytic Abatement of Environmental Pollutants and Greenhouse Gases in Automotive, Natural Gas Vehicles, and Stationary Power Plant Applications." Thesis, 2016. https://doi.org/10.7916/D89K4B5K.
Full textAbstract:
The present dissertation covers three research topics on catalytic environmental emissions control, including (1) aging and regeneration mechanisms of Rh- and Pd- model three-way catalysts (TWC) for gasoline automotive emission control, (2) catalytic methane emissions abatement from natural gas vehicles, and (3) scale-up of CO₂ capture and methanation using dual functional catalytic materials. The study resulted in two peer-reviewed publications, two future papers and one patent application which is currently under review.
Modern TWC use supported two separate catalyst layers on a monolith containing one Pd and the other Rh for the emissions control of CO, HC and NOₓ. The rhodium (Rh) metallic component (active for NOₓ reduction) experiences the most severe oxidative thermal deactivation (forming inactive Rh³⁺) during fuel cutoff, an engine mode (e.g., at downhill coasting) used for enhancing fuel economy. In a subsequent switch to a slightly fuel rich condition, in situ catalyst regeneration is accomplished by the reduction of the Rh³⁺ with H₂ generated through steam reforming catalyzed by residual Rh⁰ sites. The present thesis reports the effects of the deactivation and regeneration processes on the activity, stability and structural properties of 0.5% Rh/Al₂O₃ and 0.5% Rh/Ce_xO_y-ZrO₂ (CZO) as model catalysts. Both materials are used to varying extents in modern TWC. A very brief introduction of three-way catalysis and system considerations will be presented.
During simulated fuel cutoff, catalyst deactivation is accelerated with increasing aging temperature from 800 °C to 1050 °C. Rh on a CZO support experiences less deactivation and faster regeneration than Rh on Al₂O₃. Catalyst characterization techniques including BET surface area, CO chemisorption, temperature programmed reduction, and x-ray photoelectron spectroscopy, transmission electron microscopy, scanning-electron microscopy, and x-ray diffraction measurements were applied to examine the role of metal-support interactions in each catalyst system. For Rh/Al₂O₃, strong metal-support interactions leading to the formation of a stable rhodium aluminate (Rh(AlO₂)_y) complex dominates during fuel cutoff, resulting in more difficult catalyst regeneration (reduction). For Rh/CZO, Rh sites were partially oxidized to Rh₂O₃ and were relatively easy to be reduced to active Rh⁰ during regeneration.
Moderate Pd and support sintering of Pd-Ce_xO_y is experienced upon aging, but with a minimal effect on the catalyst activity. Cooling in air, following aging, was not able to reverse the metallic Pd sintering by re-dispersing to PdO. Unlike the aged Rh-TWCs, reduction via in situ steam reforming (SR) of exhaust HCs was not effective in reversing the deactivation of aged Pd/Al₂O₃, but did show a slight recovery of the Pd activity when CZO was the carrier. The Pd⁺/Pd⁰ and Ce³⁺/Ce⁴⁺ couples in Pd/CZO are reported to promote the catalytic SR by improving the redox efficiency during the regeneration, while no such promoting effect was observed for Pd/Al₂O₃. A suggestion is made for improving the catalyst performance.
The use of natural gas for vehicle applications is growing in popularity due to advanced fracking technology. Exhaust methane has been excluded from regulations since it does not participate in photochemical reactions. New vehicle environmental regulations are expected for controlling methane emissions given their contribution to the greenhouse gas effects. Methane is extremely resistant to oxidation when the natural gas-fueled engine operates in the stoichiometric mode with a supported Rh-Pd three-way catalyst (TWC). Furthermore, vehicles will still operate with fuel cutoff (for enhanced fuel economy), resulting in thermal oxidative deactivation (1050 °C) of the Rh metal in TWC to inactive Rh³⁺, resulting in a loss of both NOₓ and methane abatement activity. When the engine returns to the slightly rich mode, H₂ generated by methane steam reforming does not readily occur to reduce and regenerate the Rh. We report a solution to methane emissions abatement by catalytic reforming of an injected aqueous solution of ethanol into the simulated exhaust stream in TWC mode, which generates sufficient H₂ to regenerate especially Rh by reducing Rh³⁺ to its metallic active state.
Conventional CO₂ capture and sequestration (CCS) in aqueous alkaline solutions is a very energy-intensive process with relative unstable performance and low efficiency especially for power plant effluents, and therefore there is a need for new approaches to control green house gas emissions of CO₂. Here we report on progress with an advanced technology involving CO₂ adsorption from flue gas and synthetic natural gas production, via methanation, both performed at the same temperature with the addition of renewable H₂ and by using a dual functional material (DFM). The stored H₂ used is produced by water electrolysis during those times when solar, wind, and other alternative energies generate excess power out of phase with the direct use of the electricity. The DFM is composed of nano-dispersed CaO (or Na₂CO₃) and Ru metal supported on γAl₂O₃ carrier, respectively functioning as the CO₂ adsorbent and methanation catalyst. The present paper focuses on a laboratory scale-up study by using a simulated flue gas and 5%Ru,10%CaO/Al₂O₃ and 5% Ru,10%Na₂CO₃/Al₂O₃ DFM samples. The effects of DFM preparation methods, Al₂O₃ carrier materials (with different shapes and properties), and adsorption and methanation conditions (feed compositions, flow rates, reaction temperatures) on the DFM performance were examined. Samples were prepared using chloride precursor salts and showed stable performance under pseudo scale-up conditions, with SASOL TH100 Al₂O₃ (with the highest BET surface area and pore volume/radius among the support materials) exhibiting the best performance. Compared to Ru-CaO, Ru-Na₂CO₃ based DFM materials showed improved CO₂ utilization and methanation production. Reaction conditions were explored to find optimized CO₂ adsorption and methanation.
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Dreier, Sebastian. "The Impact of Films on the Long-Term Behavior of Stationary Electrical Connections and Contacts in Electric Power Systems." Doctoral thesis, 2015. https://tud.qucosa.de/id/qucosa%3A29263.
Full textAbstract:
Stationary electrical connections and contacts, such as power connections, are commonly applied in electric power systems used for generation, transmission and distribution of electric energy. Several different degradation mechanisms can increase the contact resistance and might therefore reduce the power connection’s lifetime. The degradation by film development as a result of chemical reactions is often considered as a reason for contact failure.
In this research work, the impact of film development produced by chemical reactions, such as oxidation, on the long-term behavior of stationary electrical connections and contacts was studied with crossed rods. Analytical, numerical and experimental methods were applied. Typical material systems for electric power systems were considered in this study: Cu-ETP (CW004A) bare, silver-, nickel- or tin-coated, Al99.5 (EN AW-1050A) and AlMgSi0.5 (EN AW-6060).
By applying numerical methods, the mechanical stress distribution was determined within a circular contact point. The initial contact resistance and the plastic deformed area of the considered material systems was measured in experimental tests. The film’s impact was further determined through comparative experimental studies in air (standard atmosphere) and N2 (inert gas).
During the experimental tests on perpendicularly crossed rods, other degradation mechanisms such as force reduction were suppressed. The film’s impact within the formation phase was studied on copper rods in an oven at 200 °C for 1000 h. Moreover, the dependency on different environments at 90 °C (laboratory, botanical garden and outdoor) was tested for 12000 h. Additional long-term tests over 12000 h were conducted at 200 °C. The contact resistance was determined dependent on time. Furthermore, the plastic deformed area was ascertained by microscopy. It was found that the time dependent film development caused by chemical reactions such as oxidation might possibly not result in a significant degradation of stationary electrical contacts with circular contact points and a constant force.
Supplementary studies were performed at 200 °C for 1000 h with perpendicularly crossed rods at low forces (3.5 N) as well as analytical assessment of radial and axial film growth on circular contact points. The measured long-term behavior of perpendicularly crossed rods was similar for low and high forces.
In order to study the long-term behavior of power connections operated in areas with harsh environmental conditions, experimental field tests on bolted busbar joints were conducted in desert and tropical rainforest environments. For over two and a half years, long-term field tests investigating bolted busbar joints made of Cu-ETP, Al99.5 (EN-AW-1350A) or AlMgSi0.5 (EN AW-6060) either with or without coating (silver, tin or nickel) were conducted in Belém (Brazil), Ismailia (Egypt) and Dresden (Germany).
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Chen, Jian-an, and 陳建安. "The Research of the Bio-Hydrogen Stationary Fuel Cell Power Systems consumers purchase intention - Taichung City residents in apartment building as an Example." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/65738125984163663445.
Full textAbstract:
碩士逢甲大學
科技管理研究所
100
Because of the issues of the global warming and limitations of fossil fuels, the concept of energy saving and carbon reduction has already taken a lead, the governments are all actively involved in developing renewable energy sources around the world, and hydrogen energy is one of them. The bio-hydrogen fuel cell application is the latest innovation currently. In order to find out the acceptance of new product, this study will discuss the Bio-Hydrogen Stationary Fuel Cell Power Systems consumers purchase intention. This study adopts the Holak’s new product adoption model (1988) to be a base, use “Product attributes”, “Consumer characteristics” and “External environment” three factors to discuss the purchase intention of consumer, give community residents as example. According the result of this study, in the aspects of “Product Attributes”, the “Comparative Advantage”, “Complexity” and Observability” are significantly related to purchase intention, in the aspect of “Consumer Characteristics”, the “Physical and Financial Risk”, “Social Risk” and “Energy-Saving & Carbon Reduction” are the key factors affected willing purchase, just only the “Social Risk” is insignificant; the “External Environment” factors what affect the willing purchase of consumer are “Government Policies and Time” and “Price” are significantly. New discovery from the study is this innovative product should educate the consumer to understand it deeply, not only improve the performance, but also focus on the consumer characteristics. Therefore, government can establish the “Green Science Park”, to develop technology specification of industry, and set up the demonstration program. Furthermore, on marketing strategy, should focus on energy-saving and carbon reduction of consumer who adopts the green energy product are very strongly. The key factors which affected the purchase intention of consumer are product price and government policy, so that how to reduce the consumer switching cost and purchase subsidies are critical issues for government now.
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Chen, I.-Po, and 陳易伯. "The Power of McCabe and Tremayne Test (1995) for Difference Stationarity When the Errors are Correlated." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/zccrve.
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碩士國立中山大學
經濟學研究所
107
In this thesis, I relax McCabe and Smith (1998)’s assumptions to reconsider the power properties of McCabe and Tremayne (1995, MT) test for the difference stationarity of a times series. Without the independence assumption between the random coefficient and error process as that of McCabe and Smith (1998) , I derive the asymptotic distribution of MT test under local heteroscedastic integration alternative. I find that the MT test statistics is O(T1/4) and therefore it is diverge. In a finite sample, the power increase as the correlation or the variance of error process increase. Monte Carlo evidence supports our theoretical findings.
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"Enhanced Power System Operational Performance with Anticipatory Control under Increased Penetration of Wind Energy." Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.40225.
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abstract: As the world embraces a sustainable energy future, alternative energy resources, such as wind power, are increasingly being seen as an integral part of the future electric energy grid. Ultimately, integrating such a dynamic and variable mix of generation requires a better understanding of renewable generation output, in addition to power grid systems that improve power system operational performance in the presence of anticipated events such as wind power ramps. Because of the stochastic, uncontrollable nature of renewable resources, a thorough and accurate characterization of wind activity is necessary to maintain grid stability and reliability. Wind power ramps from an existing wind farm are studied to characterize persistence forecasting errors using extreme value analysis techniques. In addition, a novel metric that quantifies the amount of non-stationarity in time series wind power data was proposed and used in a real-time algorithm to provide a rigorous method that adaptively determines training data for forecasts. Lastly, large swings in generation or load can cause system frequency and tie-line flows to deviate from nominal, so an anticipatory MPC-based secondary control scheme was designed and integrated into an automatic generation control loop to improve the ability of an interconnection to respond to anticipated large events and fluctuations in the power system.Dissertation/Thesis
Doctoral Dissertation Electrical Engineering 2016