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Islam, Saif Ul. "Energy management in content distribution network servers." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30007/document.
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Les infrastructures Internet et l'installation d'appareils très gourmands en énergie (en raison de l'explosion du nombre d'internautes et de la concurrence entre les services efficaces offerts par Internet) se développent de manière exponentielle. Cela entraîne une augmentation importante de la consommation d'énergie. La gestion de l'énergie dans les systèmes de distribution de contenus à grande échelle joue un rôle déterminant dans la diminution de l'empreinte énergétique globale de l'industrie des TIC (Technologies de l'information et de la communication). Elle permet également de diminuer les coûts énergétiques d'un produit ou d'un service. Les CDN (Content Delivery Networks) sont parmi les systèmes de distribution à grande échelle les plus populaires, dans lesquels les requêtes des clients sont transférées vers des serveurs et traitées par des serveurs proxy ou le serveur d'origine, selon la disponibilité des contenus et la politique de redirection des CDN. Par conséquent, notre objectif principal est de proposer et de développer des mécanismes basés sur la simulation afin de concevoir des politiques de redirection des CDN. Ces politiques prendront la décision dynamique de réduire la consommation d'énergie des CDN. Enfin, nous analyserons son impact sur l'expérience utilisateur. Nous commencerons par une modélisation de l'utilisation des serveurs proxy et un modèle de consommation d'énergie des serveurs proxy basé sur leur utilisation. Nous ciblerons les politiques de redirection des CDN en proposant et en développant des politiques d'équilibre et de déséquilibre des charges (en utilisant la loi de Zipf) pour rediriger les requêtes des clients vers les serveurs. Nous avons pris en compte deux techniques de réduction de la consommation d'énergie : le DVFS (Dynamic Voltage Frequency Scaling) et la consolidation de serveurs. Nous avons appliqué ces techniques de réduction de la consommation d'énergie au contexte d'un CDN (au niveau d'un serveur proxy), mais aussi aux politiques d'équilibre et de déséquilibre des charges afin d'économiser l'énergie. Afin d'évaluer les politiques et les mécanismes que nous proposons, nous avons mis l'accent sur la manière de rendre l'utilisation des ressources des CDN plus efficace, mais nous nous sommes également intéressés à leur coût en énergie, à leur impact sur l'expérience utilisateur et sur la qualité de la gestion des infrastructures. Dans ce but, nous avons défini comme métriques d'évaluation l'utilisation des serveurs proxy, d'échec des requêtes comme les paramètres les plus importants. Nous avons transformé un simulateur d'événements discrets CDNsim en Green CDNsim, et évalué notre travail selon différents scénarios de CDN en modifiant : les infrastructures proxy des CDN (nombre de serveurs proxy), le trafic (nombre de requêtes clients) et l'intensité du trafic (fréquence des requêtes client) en prenant d'abord en compte les métriques d'évaluation mentionnées précédemment. Nous sommes les premiers à proposer un DVFS et la combinaison d'un DVFS avec la consolidation d'un environnement de simulation de CDN en prenant en compte les politiques d'équilibre et de déséquilibre des charges. Nous avons conclu que les techniques d'économie d'énergie permettent de réduire considérablement la consommation d'énergie mais dégradent l'expérience utilisateur. Nous avons montré que la technique de consolidation des serveurs est plus efficace dans la réduction d'énergie lorsque les serveurs proxy ne sont pas beaucoup chargés. Dans le même temps, il apparaît que l'impact du DVFS sur l'économie d'énergie est plus important lorsque les serveurs proxy sont bien chargés. La combinaison des deux (DVFS et consolidation des serveurs) permet de consommer moins d'énergie mais dégrade davantage l'expérience utilisateur que lorsque ces deux techniques sont utilisées séparémentExplosive increase in Internet infrastructure and installation of energy hungry devices because of huge increase in Internet users and competition of efficient Internet services causing a great increase in energy consumption. Energy management in large scale distributed systems has an important role to minimize the contribution of Information and Communication Technology (ICT) industry in global CO2 (Carbon Dioxide) footprint and to decrease the energy cost of a product or service. Content distribution Networks (CDNs) are one of the popular large scale distributed systems, in which client requests are forwarded towards servers and are fulfilled either by surrogate servers or by origin server, depending on contents availability and CDN redirection policy. Our main goal is therefore, to propose and to develop simulation-based principled mechanisms for the design of CDN redirection policies which will do and carry out dynamic decisions to reduce CDN energy consumption and then to analyze its impact on user experience constraints to provide services. We started from modeling surrogate server utilization and derived surrogate server energy consumption model based on its utilization. We targeted CDN redirection policies by proposing and developing load-balance and load-unbalance policies using Zipfian distribution, to redirect client requests to servers. We took into account two energy reduction techniques, Dynamic Voltage Frequency Scaling (DVFS) and server consolidation. We applied these energy reduction techniques in the context of a CDN at surrogate server level and injected them in load-balance and load-unbalance policies to have energy savings. In order to evaluate our proposed policies and mechanisms, we have emphasized, how efficiently the CDN resources are utilized, at what energy cost, its impact on user experience and on quality of infrastructure management. For that purpose, we have considered surrogate server's utilization, energy consumption, energy per request, mean response time, hit ratio and failed requests as evaluation metrics. In order to analyze energy reduction and its impact on user experience, energy consumption, mean response time and failed requests are considered more important parameters. We have transformed a discrete event simulator CDNsim into Green CDNsim and evaluated our proposed work in different scenarios of a CDN by changing: CDN surrogate infrastructure (number of surrogate servers), traffic load (number of client requests) and traffic intensity (client requests frequency) by taking into account previously discussed evaluation metrics. We are the first who proposed DVFS and the combination of DVFS and consolidation in a CDN simulation environment, considering load-balance and loadunbalance policies. We have concluded that energy reduction techniques offer considerable energy savings while user experience is degraded. We have exhibited that server consolidation technique performs better in energy reduction while surrogate servers are lightly loaded. While, DVFS impact is more considerable for energy gains when surrogate servers are well loaded. Impact of DVFS on user experience is lesser than that of server consolidation. Combination of both (DVFS and server consolidation) presents more energy savings at higher cost of user experience degradation in comparison when both are used individually
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Farahat, Sameer Ismail. "Electron energy distribution functions in radio-frequency discharges." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361940.
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Pedersen, Linda. "Load Modelling of Buildings in Mixed Energy Distribution Systems." Doctoral thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1562.
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The main topic of this thesis has been the development of a new method for load modelling of buildings in mixed energy distribution systems. The method estimates design load profiles, yearly load profiles, load duration profiles and annual expected energy demand for a specified planning area, all divided into heat and electricity purposes. The heat load demand includes end-uses such as space heating, ventilation heating and hot tap water, while electricity load demand includes end-uses such as lighting, pumps, fans, and electrical appliances.
The model has been based on statistical analyses of simultaneous hourly district heat and electricity consumption data for a number of buildings. Consumption data have been collected from TEV Fjernvarme and BKK Varme, two district heating companies in Trondheim and Bergen respectively.
The heat load model has been based on piece-wise linear regression analyses to estimate the change-point temperature for temperaturedependent heat consumption. Linear regression analyses have been performed on the temperature-dependent consumption for all hours of the day for two different day types, weekdays and weekends/holidays. The normal distribution has been used on the temperature-independent consumption, which is mainly hot tap water. Expected values and standard deviations for all buildings analysed have been calculated for both temperature-dependent and temperature-independent consumption.
The electricity load model has been based on continuous probability distributions, such as normal distribution, lognormal distribution and Student’s t distribution. The last distribution has shown the best fit for all hours and day types in most cases. Expected values and standard deviations for all buildings analysed have been calculated for winter, spring/fall and summer seasons.
Generalised relative load profiles have been developed for various building categories based on the heat and electricity load model. Single family houses and apartment blocks, office buildings, educational buildings, hospital buildings, and hotels and restaurants are the building categories that have been analysed. Specific heat and electricity load and energy indicators, given in [W/m2] and [ kWh/m2], have also been developed for all building categories. The specific load indicators have been used to restore the design load profiles from relative to real values in order to find the maximum heat and electricity demand for a specified planning area. The specific energy indicators have been used to convert the normalised yearly load profiles, and consequently, the normalised load duration profiles into real values.
A method for load aggregation for a specified planning area has also been developed based on the sum of independent variables from the same distribution. 95% quantile analysis based on the Student’s t distribution has been applied to incorporate the uncertainty in the load profiles developed. The installed capacity, and thereby the investment costs for the energy production unit(s) and distribution system(s), are decided by the design load profiles and load duration profiles. The system’s operation costs are given by the yearly load profiles and annual expected energy demand.
A theoretical case study has been performed to illustrate how to apply the generalised relative load profiles, along with the specific load and energy indicators, for the purpose of planning for mixed energy distribution systems.
Paper II reprinted with kind permission of Elsevier, sciencedirect.com
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Wilbur, Thomas M. "Energy distribution of Cerenkov radiation for finite frequency intervals." Thesis, Monterey, California. Naval Postgraduate School, 1987. http://hdl.handle.net/10945/22254.
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Gutierrez, Lagos Luis Daniel. "Advanced voltage control for energy conservation in distribution networks." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/advanced-voltage-control-for-energy-conservation-in-distribution-networks(2718dcf1-f5db-45df-84e2-4890956ba8b1).html.
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The increasing awareness on the effect of carbon emissions in our planet has led to several countries to adopt targets for their reduction. One way of contributing to this aim is to use and distribute electricity more efficiently. In this context, Conservation Voltage Reduction (CVR), a well-known technique that takes advantage of the positive correlation between voltage and demand to reduce energy consumption, is gaining renewed interest. This technique saves energy by only reducing customer voltages, without relying on customer actions and, therefore, can be controlled by the Distribution Network Operator (DNO). CVR not only brings benefits to the electricity system by reducing generation requirements (fewer fossil fuel burning and carbon emissions), but also to customers, as energy bill reductions. The extent to which CVR can bring benefits mainly depends on the customers load composition and their voltages. While the former dictates the voltage-demand correlation, the latter constraints the voltage reduction that can be applied without violating statutory limits. Although CVR has been studied for many years, most of the studies neglect the time-varying voltage-demand characteristic of loads and/or do not assess end customer voltages. While these simplifications could be used to estimate CVR benefits for fixed and limited voltage reductions, realistic load and network models are needed to assess the performance of active CVR schemes, where voltages are actively managed to be close to the minimum limit. Moreover, distribution networks have been traditionally designed with limited monitoring and controllability. Therefore, CVR has been typically implemented by adopting conservative voltage reductions from primary substations, for both American and European-style networks. However, as new infrastructure is deployed in European-style LV networks (focus of this work), such as monitoring and on-load tap changers (OLTCs), the opportunity arises to actively manage voltages closer to end customer (unlocking further energy savings). Although these technologies have shown to effectively control voltages in LV networks, their potential for CVR has not been assessed before. Additionally, most CVR studies were performed in a context where distributed generation (DG) was not common. However, this has changed in many countries, with residential photovoltaic (PV) systems becoming popular. As this is likely to continue, the interactions of residential PV and CVR need to be studied. This thesis contributes to address the aforementioned literature gaps by: (i) proposing a simulation framework to characterise the time-varying voltage-demand correlation of individual end customers; (ii) developing a process to model real distribution networks (MV and LV) from DNO data; (iii) adopting a Monte Carlo-based quantification process to cater for the uncertainties related to individual customer demand; (iv) assessing the CVR benefits that can be unlocked with new LV infrastructure and different PV conditions. To accomplish (iv), first, a simple yet effective rule-based scheme is proposed to actively control voltages in OLTC-enabled LV networks without PV and using limited monitoring. It is demonstrated that by controlling voltages closer to customers, annual energy savings can increase significantly, compared to primary substation voltage reductions. Also, to understand the effect of PV on CVR, a centralized, three-phase AC OPF-based CVR scheme is proposed. This control, using monitoring, OLTCs and capacitors across MV and LV networks, actively manages voltages to minimize energy consumption in high PV penetration scenarios whilst considering MV-LV constraints. Results demonstrate that without CVR, PV systems lead to higher energy imports for customers without PV, due to higher voltages. Conversely, the OPF-based CVR scheme can effectively manage voltages throughout the day, minimising energy imports for all customers. Moreover, if OLTCs at secondary substations are available (and managed in coordination with the primary substation OLTC), these tend to regulate customer voltages close to the minimum statutory limit (lower tap positions), while the primary OLTC delivers higher voltages to the MV network to also reduce MV energy losses.
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AbdelMeguid, Hossam Saadeldin. "Pressure, leakage and energy management in water distribution systems." Thesis, De Montfort University, 2011. http://hdl.handle.net/2086/4905.
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A fast and efficient method to calculate time schedules for internal and boundary PRVs and flow modulation curves has been developed and implemented. Both time and flow modulation can be applied to a single inlet DMA. The time modulation methodology is based on solving a nonlinear programming problem (NLP). In addition, Genetic Algorithms (GA) has been proposed and investigated to calculate the optimal coefficients of a second order relationship between the flow and the outlet pressure for a PRV to minimize the background leakage. The obtained curve can be subsequently implemented using a flow modulation controller in a feedback control scheme. The Aquai-Mod® is a hydraulic device to control and modulate the outlet pressure of a PRV according to the valve flow. The controller was experimentally tested to assess its performance and functionality in different conditions and operating ranges. The mathematical model of the controller has been developed and solved, in both steady state and dynamic conditions. The results of the model have been compared with the experimental data and showed a good agreement in the magnitude and trends. A new method for combined energy and pressure management via integration and coordination of pump scheduling with pressure control aspects has been created. The method is based on formulating and solving an optimisation NLP problem and involves pressure dependent leakage. The cost function of the optimisation problem represents the total cost of water treatment and pumping energy. Developed network scheduling algorithm consists of two stages. The first stage involves solving a continuous problem, where operation of each pump is described by continuous variable. Subsequently, the second stage continuous pump schedules are discretised using heuristic algorithm. Another area of research has been developing optimal feedback rules using GA to control the operation of pump stations. Each pump station has a rule described by two water levels in a downstream reservoir and a value of pump speed for each tariff period. The lower and upper water switching levels of the downstream reservoir correspond to the pump being “ON” or “OFF”. The achieved similar energy cost per 1 Ml of pumped water. In the considered case study, the optimal feedback rules had advantage of small number of ON/OFF switches, which increase the pump stations lifetime and reduce the maintenance cost as well.
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Molina, Gustavo Jose. "Triboemission From Ceramics: Charge Intensity and Energy Distribution Characterizations." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28217.
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Lubrication of ceramics is a difficult and not completely solved problem. Ceramics do not respond to conventional lubricants which are designed to function by a chemical reaction with the surface. There is, accordingly, increased interest in the development of lubrication alternatives for ceramics, and in understanding the tribochemical fundamentals by which new lubrication processes can be designed and controlled. In particular, the mechanism of tribopolymerization for some addition-type monomers is thought to be initiated and controlled by triboemitted low-energy electrons.
This Ph.D. dissertation presents the experimental work carried out at the Virginia Polytechnic Institute and State University for the characterization of charge intensity and energy distribution of charged-particles triboemitted from sliding contacts of ceramics.
A review is presented of research work on tribochemistry and, in particular, on tribopolymerization as a lubrication mechanism. Relevant literature is also reviewed on the phenomena of exoemission, triboemission and fractoemission of charged-particles. The design, construction and development of a new instrument and data acquisition system to carry out triboemission measurements under high vacuum and for controlled load, sliding speed and retarding grid-voltage is described.
The charge intensity is characterized of the particles triboemitted from two related ceramics, alumina and sapphire, and from one metallic material, i.e., aluminum, when scratched by a diamond pin.
In the case of alumina, triboemitted-charge intensity also is studied by sliding contact of an alumina ball. Burst-type negatively-charged particle triboemission was observed from diamond-on-alumina, diamond-on-sapphire, and alumina-on-alumina sliding contacts. The different crystalline structure, i.e., of alumina and sapphire, does not appear to be a factor in electron triboemission. In general, large bursts of electron triboemission may appear superimposed on a constant lower level of small-burst emission. This constant level, being higher than background-noise, does not vary between different ceramic specimens, while maximum levels of triboemission-bursts differ by two orders of magnitude between different specimens. The characteristic decay-time of the triboemission bursts is found of about 100ms. Lower-level decaying post-contact emission of negatively-charged particles from ceramics is observed.
Low negatively-charged triboemission was observed from diamond-on-aluminum sliding contacts. The positively-charged triboemission from these sliding material systems was also measured. Low positive-ion emission, barely above background level, was observed for the diamond-on-ceramics and alumina-on-alumina systems.
The retarded-energy spectra of the negatively-charged particle triboemissions from ceramics were also obtained. Such spectra show decaying rates of triboemission for increasing minimum energy of the triboemitted particles: an important fraction of the total electron triboemission is produced in the zero to 5eVolts energy-range, with a decaying tail extending beyond the test maximum level of 48 Volts.
These experimental measurements are discussed with a focus on the possible role of triboemitted charged-particles in tribopolymerization as a mechanism of ceramic lubrication. It is concluded that low-energy electrons are emitted in bursts from ceramics under sliding contact, the essential first step in the hypotheses of tribopolymerization of certain addition-type monomers, while positively-charged emission is negligible. These findings strongly support tribopolymerization results from previous research.
A frequency domain analysis of the triboemission data is carried out. For the electron-triboemission outputs, a characteristic pattern is found for the experimentally estimated frequencies of occurrence of the triboemitted particles. A new probability distribution, called "Convoluted Poisson" is developed to describe this triboemission data. Good agreement is found between the probabilities of triboemitted-particle occurrence, as predicted by such distribution, and the experimental probabilities estimated from triboemission outputs. The significance of the two parameters defining this "Convoluted Poisson" distribution is explored and discussed with a focus on basic surface-change phenomena.Ph. D.
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Ding, Fei. "Smart Distribution System Automation: Network Reconfiguration and Energy Management." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1417291114.
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Maleki, Delarestaghi Javid. "Planning of power distribution networks in local energy communities." Thesis, Maleki Delarestaghi, Javid (2021) Planning of power distribution networks in local energy communities. PhD thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/61844/.
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Recent technological advances, the global understanding of climate change and the role that renewable energy resources can play, along with the rise in electricity prices and little incentive for feeding the excess PV generation back to the grid have led to the growing interest among end-users in residential solar photovoltaic (PV) systems with battery storage systems. The recently released Western Australian Climate Policy sets the goal of achieving net-zero greenhouse gas emissions (GGE) by 2050. The rapid growth in distributed energy resources (DER) has changed the load pattern in distribution networks (DNs). As more DER facilities are introduced to the electric power systems, the power utilities undertake more investments in infrastructure to tackle the uncertainties pertaining to DER and manage the voltage issues due to increasing DER penetration. In these cases, the conventional planning models will result in over- or under-investment choices due to limited knowledge about end-users, which ultimately leads to financial losses for both the utility and customers.
In order to effectively plan DNs for the future utilities need to understand the possible changes at the end-users’ side, which is missing in the existing literature. To achieve the optimal plan for the modern power distribution networks, all parties should be considered including the utility and end-users. There is also a critical need for better network charge tariffs designs to reflect the true contribution of customer DER in the cost of poles and wires. This thesis studies planning models for power utilities incorporating a model of end-users’ decisions. This enables utilities to see the most likely possible scenarios of end-users’ investment in DER.
The main contributions of this thesis are:
1. Development of a DN planning model that incorporates the expected end-users’ investments in DER. This model enables the utility to investigate the opportunities and challenges offered by end-users’ DER and presents more cost-effective investment plans for the utility.
2. Further development of a DN planning model through formulating a separate optimisation problem for the end-users. This model allows both the utility and end-uses to maximise their own benefits.
3. Inclusion of a local energy market where end-users can trade energy with other end-users in their neighbourhood providing more convenient prices for buyers and higher benefits for sellers.
4. Design of a network charge allocation scheme for the utility to rationalise the network use. This will help the utility to avoid unnecessary investment in the network.
5. Development of solution techniques using distributed optimisation algorithms and decomposition techniques to enhance the computation speed.
6. Formulation of a novel optimal power flow problem based on the concept of the Stackelberg game and Benders decomposition. This model provides more cost-effect solutions and is faster than existing models.
The simulations reveal that the proposed planning model enables power utilities to avoid overinvestments while motivating the increased installation of DER by end-users. In essence, the numerical studies show that the proposed planning model led to 75% reduction in the cost of network investment and 70% reduction in the total cost of planning and operation for the utility compared to existing planning models. As well as this the penetration of customer DER increased by 20% using our proposed model. The proposed model also reduced the total cost of electrification by 4%.
The numerical studies also show that the proposed dynamic network charge tariff design can effectively reflect the true contribution of customers to the cost of network upgrade. Essentially, the loading of lines and distribution transformers decreased by up to 30% which resulted in lower grid losses and avoided unnecessary costly infrastructure investments. The deviation of the node voltages from 1 per unit was also improved by a factor of 11%.
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Zhang, Chenghua. "Peer-to-peer energy trading in electrical distribution networks." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/109074/.
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In response to the challenges posed by the increasing penetration of distributed generation from renewable energy sources and the increasing electricity retail prices with decreasing Feed-In Tariff rates, a new energy trading arrangement, “peer-to-peer (P2P) energy trading” has been proposed. It refers to the direct energy trading among consumers and prosumers in distribution networks, which is developed based on the “P2P economy” concept (also known as sharing economy). A hierarchical system architecture model has been proposed in order to identify and categorise the key elements and technologies involved in P2P energy trading. A P2P energy trading platform called “Elecbay” is designed. The P2P bidding is simulated using game theory. Test results in a grid-connected LV Microgrid with distributed generators and flexible demands show that P2P energy trading is able to improve the local balance of energy generation and consumption, and the enhanced variety of peers is able to further facilitate the balance. Two necessary control systems are proposed for the Microgrid with “Elecbay”. A voltage control system which combines droop control and on-load-tap-changer (OLTC) control is designed and simulated. Simulation results show that the proposed voltage control system is sufficient for supporting the P2P energy trading in the Microgrid. The total number of operation times of the OLTC is reduced with P2P energy trading compared to the reference scenario. The information and communication technology (ICT) infrastructures for the P2P bidding platform and the voltage control system are investigated. The information exchange among peers and other parties (Elecbay, distribution system operators, etc.) is designed based on TCP/IP protocol. Existing and private communication networks with different communication medium, bandwidths, etc., are modelled. Simulation results show that the existing ICT infrastructures are sufficient for supporting both the P2P energy trading platform and the voltage control system. Therefore, no large amount of additional investments are required.
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Gasteen, M. R. "Propagation of mains marked control signals on an electricity distribution network." Thesis, University of Bristol, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354449.
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Jones, M. "The variability and spectral energy distribution of active galactic nuclei." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233259.
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Weerasinghe, Handuwala Dewage Dulan Jayanatha. "Planning optimal load distribution and maximum renewable energy from wind power on a radial distribution system." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/28714.
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Doctor of PhilosophyElectrical and Computer Engineering
Ruth D. Miller
Optimizing renewable distributed generation in distribution systems has gained popularity with changes in federal energy policies. Various studies have been reported in this regard and most of the studies are based on optimum wind and/or solar generation planning in distribution system using various optimization techniques such as analytical, numerical, and heuristic. However, characteristics such as high energy density, relatively lower footprint of land, availability, and local reactive power compensation ability, have gained increased popularity for optimizing distributed wind generation (DWG) in distribution systems. This research investigated optimum distributed generation planning (ODGP) using two primary optimization techniques: analytical and heuristic. In first part of the research, an analytical optimization method called “Combined Electrical Topology (CET)” was proposed in order to minimize the impact of intentional structural changes in distribution system topology, in distributed generation/ DWG placement. Even though it is still rare, DWG could be maximized to supply base power demand of three-phase unbalanced radial distribution system, combined with distributed battery energy storage systems (BESS). In second part of this research the usage of DWG/BESS as base power generation, and to extend the ability to sustain the system in a power grid failure for a maximum of 1.5 hours was studied. IEEE 37-node, three-phase unbalanced radial distribution system was used as the test system to optimize wind turbines and sodium sulfide (NaS) battery units with respect to network real power losses, system voltage profile, DWG/BESS availability and present value of cost savings. In addition, DWG’s ability to supply local reactive power in distribution system was also investigated. Model results suggested that DWG/NaS could supply base power demand of a threephase unbalanced radial distribution system. In addition, DWG/NaS were able to sustain power demand of a three-phase unbalanced distribution system for 1.5 hours in the event of a power grid failure.
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Roe, Curtis Aaron. "Impacts of automated residential energy management technology on primary energy source utilization." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45865.
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The objective of the proposed research is to analyze automated residential energy management technology using primary energy source utilization. A residential energy management system (REMS) is an amalgamation of hardware and software that performs residential energy usage monitoring, planning, and control. Primary energy source utilization quantifies power system levels impacts on power generation cost, fuel utilization, and environmental air pollution; based on power system generating constraints and electric load.
Automated residential energy management technology performance is quantified through a physically-based REMS simulation. This simulation includes individual appliance operation and accounts for consumer behavior by stochastically varying appliance usage and repeating multiple simulation iterations for each simulated scenario. The effect of the automated REMS under varying levels of control will be considered.
Aggregate REMS power system impacts are quantified using primary energy source utilization. This analysis uses a probabilistic economic dispatch algorithm. The economic dispatch algorithm quantifies: fuel usage and subsequent environmental air pollution (EAP) generated; based on power system generating constraints and electric load (no transmission constraints are considered).
The analysis will comprehensively explore multiple residential energy management options to achieve demand response. The physically-based REMS simulation will consider the following control options: programmable thermostat, direct load control, smart appliance scheduling, and smart appliance scheduling with a stationary battery. The ability to compare multiple automated residential energy management technology options on an equal basis will guide utility technology investment strategies.
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Aschenauer, Elke Caroline. "Cascade processes and kinetic energy distribution of pionic hydrogen atoms /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10779.
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Han, Xue. "Quantitative Analysis of Distributed Energy Resources in Future Distribution Networks." Thesis, KTH, Industriella informations- och styrsystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98484.
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There has been a large body of statements claiming that the large scale deployment of Distributed Energy Resources (DERs) will eventually reshape the future distribution grid operation in numerous ways. However, there is a lack of evidence specifying to what extent the power system operation will be alternated. In this project, quantitative results in terms of how the future distribution grid will be changed by the deployment of distributed generation, active demand and electric vehicles, are presented. The quantitative analysis is based on the conditions for both a radial and a meshed distribution network. The input parameters are on the basis of the current and envisioned DER deployment scenarios proposed for Sweden. The simulation results indicate that the deployment of DERs can significantly reduce the power losses and voltage drops by compensating power from the local energy resources, and limiting the power transmitted from the external grid. However, it is notable that the opposite results (e.g., severe voltage uctuations, larger power losses) can be obtained due to the intermittent characteristics of DERs and the irrational management of different types of DERs in the DNs. Subsequently, this will lead to challenges for the Distribution System Operator (DSO).
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Whitehead, Lorne Arthur. "Transport and distribution of light energy for illuminating engineering applications." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29318.
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This thesis concerns the transport of light along a class of cylindrical hollow optical structures, with an aim to develop practical light transport and distribution systems for illuminating engineering applications.
Based on intuition, it is postulated that it may be possible to guide light energy in a hollow cylindrical optical structure, by means of total internal reflection on the external surfaces. Such a development would allow light to be guided with the efficiency of optical fibres, but with reduced material costs.
In order to assess this possibility, a new technique is presented for analytic ray tracing in general cylindrical structures. The technique makes it possible to trace ray paths in the cross sectional plane of the structure, with the motion in the dimension out of the cross sectional plane precisely taken into account with a simple correction. This technique greatly simplifies the ray tracing calculations which are necessary to study the light transport properties of the proposed structures. It is then shown with the aid of this technique that a certain class of prismatic structures do indeed have the capability of guiding light, and members of this class are termed prism light guides.
In any real prism light guide, light is not conducted perfectly, but is lost as a result of a number of deviations from the ideal model. Of these, the one intrinsic loss mechanism, which distinguishes a prism light guide from optical fibres, is diffraction at the corners of the prismatic surfaces. Fortunately, diffraction effects are significantly smaller than losses from practical imperfections in prism light guides. A detailed study of the other types of loss mechanisms is then presented. These arise from imperfections of the optical material comprising the prism light guide (absorption and scatter), and imperfections in the shape of the prism light guide. The importance of these effects is discussed first in an approximate assessment, and they are then modelled precisely by means of computer ray tracing Monte Carlo techniques. These predictions are compared with experimental measurements of actual prism light guides, with substantial agreement.
Consideration is then given to the use of a prism light guide in illuminating engineering applications. In these situations light is distributed along the length of a prism light guide, and is uniformly emitted from the surface. The performance of such a system is modelled with Monte Carlo computer ray tracing, and experimentally tested, with substantial agreement.
This study concludes with a measurement of diffraction losses. These losses were enhanced by the use of longer wavelength radiation (3mm wavelength microwaves). The results confirm that diffraction losses are small relative to other loss mechanisms.
In general, the results reported in this thesis demonstrate the existence of a useful class of light guidance structures which are particularly well suited to the requirements for distribution and transport of optical radiation for illuminating engineering applications.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Tachtatzis, Christos. "Load distribution and energy awareness in manets using multipath routing." Thesis, University of Strathclyde, 2008. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21972.
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Wireless ad-hoc networks are characterised by lack of infrastructure and frequent topological changes. Traditional routing protocols seek only single paths to the desired destinations, while multipath routing obtains multiple paths for only marginal additional overhead. This work argues that multipath routing is advantageous, even allowing for the additional overheads, because of the improved network load distribution. The merits of multipath routing are shown through extensive performance evaluation considering packet delivery ratio, average end-to-end delay and routing efficiency, for both mobile and static scenarios. The second aspect of the thesis addresses energy awareness. When a single connection is considered, multipath routing can potentially consume more total energy compared to its unipath counterparts because some traffic can traverse longer (in terms of hop count) paths. On the other hand, unipath routing concentrates nodal traffic over the same single path; resulting in unfairness for the intermediate hops and uneven energy consumption which, in turn, can result in network partitioning. Here, it is argued that multipath routing extends the network lifetime, because the routing protocol can make more sophisticated decisions to avoid node exhaustion. Two novel energy aware routing schemes, which select optimal paths to homogenise the energy map of the network, are presented. A range of performance evaluation techniques are employed to demonstrate the merits of the proposed schemes, and it is shown that the approach of homogenising the network energy map mitigates against the effects of inevitable node outages cause by energy exhaustion and prolongs network lifetime.
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Chai, Lauren (Lauren Amy). "Twist error response of periodic lattices to strain energy distribution." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101331.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 79-80).
Periodic lattices, when used as assembly scaffolds, can augment pre-existing 2D manufacturing techniques to fabricate 3D structures with heterogeneous materials, components and architecture such as human organs for transplant patients, and micro batteries. Periodic lattices are first preformed and then folded using externally actuating walls that properly constrain the lattice edges. Angular errors of the actuation walls cause the lattice to distort, misaligning components on the lattice panels. Research into the response of a lattice to geometric errors imposed on the lattice edges does not account for how much strain energy is put into the lattice during folding and its impact on the lattice distortion response and magnitude. This thesis shows how design parameters of the lattice can change the magnitude and shape of the twist response of the lattice when external geometric errors are applied to the lattice during folding. A Buckingham Pi analysis was used to show how the twist response of the lattice due to an external angular wall error depends on the torsional stiffnesses of the panels, the initial fold angle of the preformed accordion unit in the lattice and the angular wall error. A FEA simulation study quantified the Buckingham Pi results by varying the torsional stiffness ratio of the panels, the initial fold angle and the final lattice length after folding. The results showed that increasing the ratio of the torsional stiffnesses by two orders of magnitude decreases the magnitude of the response by as much as an order of magnitude and increases the asymmetry by 0.5 to 1.5 orders of magnitude. Increasing the initial fold angle by 50% increases the magnitude of the result by as much as 250% and decreases asymmetry by 26%.
by Lauren Amy Chai.
S.M.
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Harrysson, Ralph. "Laser drilling of ceramic materials : energy distribution and crack development." Licentiate thesis, Luleå tekniska universitet, 1991. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26686.
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Venkatramanan, Adithya. "Design of control electronics for the Ram Energy Distribution Detector." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/56594.
Full textAbstract:
The bulk motion of the neutral gas at altitudes between about 200 and 600 km is an important factor in predicting the onset of plasma instabilities that are known to distort and/or disrupt high frequency radio communications. A ram wind sensor is a space science instrument that, when mounted on a satellite in low-Earth orbit, makes in-situ measurements of the component of the neutral gas velocity that lies along the orbit track of the satellite. The instrument works by changing the voltage on one of a set of grids and measuring a corresponding electron current generated by ions flowing through the grid stack and detected by the microchannel plate, generating a function of current vs. voltage called an I-V curve. Traditionally, the size and power requirements of ram wind sensors has limited their use to larger satellites. In this thesis, the electrical design and basic testing of a cubesat compatible RWS known as the ram energy distribution detector (REDD) are described.
The mechanical design of the REDD sensor is first described, and the requirements of the electrical design are presented. The electrical requirements are based on both the characteristics of the ionosphereic flight environment, and on the size and power requirements typical of the small cubesat platforms for which the instrument is intended.
The electrical hardware is then described in detail. The microcontroller design is reviewed as well, including the instrument's operating mode, and timing scheme.
Test data showing the basic functionality of the instrument are then presented. Bench tests validate the design by confirming its ability to control voltages and measure small electron currents. End-to-end tests were also performed in a vacuum chamber to mimic the ionospheric environment. These data are presented to show the ability of the REDD sensor to meet or exceed its design specifications.Master of Science
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Bigelow, Alan W. "Energy Distribution of Sputtered Neutral Atoms from a Multilayer Target." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2657/.
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Energy distribution measurements of sputtered neutral particles contribute to the general knowledge of sputtering, a common technique for surface analysis. In this work emphasis was placed on the measurement of energy distribution of sputtered neutral atoms from different depths. The liquid Ga-In eutectic alloy as a sample target for this study was ideal due to an extreme concentration ratio gradient between the top two monolayers. In pursuing this study, the method of sputter-initiated resonance ionization spectroscopy (SIRIS) was utilized. SIRIS employs a pulsed ion beam to initiate sputtering and tunable dye lasers for resonance ionization. Observation of the energy distribution was achieved with a position-sensitive detector. The principle behind the detector's energy resolution is time of flight (TOF) spectroscopy. For this specific detector, programmed time intervals between the sputtering pulse at the target and the ionizing laser pulse provided information leading to the energy distribution of the secondary neutral particles. This experiment contributes data for energy distributions of sputtered neutral particles to the experimental database, required by theoretical models and computer simulations for the sputtering phenomenon.
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Gupta, Apoorv. "Vätgaslagring, -distribution och -rening." Thesis, KTH, Skolan för kemivetenskap (CHE), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-213674.
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Rising greenhouse gas (GHG) emissions is a major cause of concern today. The primary source of energy all over the globe is fossil fuels, a non-renewable source of energy that is expected to get exhausted in the next 60-100 years. Damage to environment cannot be easily reversed but the initial steps are to reduce the damage done. Other alternative cleaner sources of energy are being looked into as viable options to replace fossil fuels. The objective of this study is to identify options for using hydrogen as an energy carrier in the future with a major focus on the transportation sector. This project is limited to theoretical study looking into the options for hydrogen storage and distribution. Gaseous and liquid hydrogen storage have been looked in to thoroughly and are far from meeting Department of Energy, USA, (DOE) ultimate targets for automobile fleets, hence a shift to other storage options is imminent. Metal hydride storage is believed to be the upcoming technology as the mid-term solution to storage issues and hence is given a lot of attention in this project. On-board storage in metal hydrides is studied and it can be concluded that no metal hydride known to us today is capable of satisfying the DOE ultimate targets. Finally, the study ends with options accessible to AGA to purchase hydrogen within Sweden and how they can be cleaned to meet the fuel cell gas purity requirements.
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Reza, C. M. F. S. "Design of Energy Mixer and Router for DC Power Packet Distribution System." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20137.
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Energy internet (EI) is introduced recently aiming to improve power system reliability, security and efficiency through advanced information and power electronic technologies. A power packet distribution system (PPDS) is a promising candidate for the EI implementation, as it transfers information alongside the distribution of electric power. The PPDS can be realized for both DC and AC power distribution. This thesis has made four key contributions to the DC-PPDS: (1) A revised PP structure is proposed, which has a reduced footer bit and hence reduction in power switching losses. A routing scheme which does not need footer bits like handshaking protocol is proposed to increase PP distribution efficiency. A new algorithm for PP generation is also proposed capable of generating the PP based on the load power requests and the source power availability. A systematic approach is given to select the energy buffer which is needed to sustain the load voltage. (2) An over-current protection (OCP) scheme based on a simple analog circuit and integrated with the PPDS is proposed to monitor and protect the system during the over-current scenario. The routing algorithm is also modified, which utilizes the information received from the OCP circuit to isolate the faulty loads without interrupting the PP delivery to the other loads. (3) A multiple- energy-source mixer based on a single-inductor, multiple-input and single-output converter structure is proposed to attain power conditioning and voltage regulation simultaneously to send power to various loads at distinct voltage levels. (4) A four-port converter-based mixer is also proposed, which can interface with battery to mitigate intermittency problem of RESs, hence ensure reliable power distribution in islanded mode. The proposed solutions have been verified through experimental results. The PPDS has the potential to be applied in systems where communication and power transfer occur simultaneously.
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Gunawardana, Prasanna M. "Deep Earthquakes Spatial Distribution| Numerical Modeling of Stress and Stored Elastic Energy Distribution within the Subducting Lithosphere." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163344.
Full textAbstract:
The spatial distribution of deep earthquakes remains elusive, as the earthquakes below 30 km depth cannot be explained using the brittle frictional processes due to the fluid behavior of rocks under high pressure and temperature conditions. Several models that have been developed to identify the source distribution fall largely into categories like negative buoyancy and viscous friction to the flow, anti-crack faulting due to metastable olivine, volume reductions from phase transformations etc. Still none of them were able to satisfactorily explain the spatial distribution of deep earthquakes. We propose a new method using the visco-elastic nature of the earth material to model the deformation, stress, and elastic energy of the subducting lithosphere using “Marker in cell method” in combination with a conservative finite difference scheme. The software is written in Python and NumPy. We have tested this code for the known results of a Rayleigh–Taylor instability of solid-fluid interaction, and for a general subduction benchmark (Schmeling et al., 2008). We show a large set of numerical models in which we investigate the role of volatiles in the transition zone by varying the viscosity of the lithosphere and the presence of a high viscosity zone below the upper-lower mantle transition zone. Finally, we compare the rate of inner energy dissipation and the stored elastic energy in the subducting lithosphere with deep earthquake spatial distribution and discuss which constrains geodynamic models offer to deep earthquake location.
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Volpe, Rosaria. "A methodology for the design of an urban energy distribution network of prosumers." Doctoral thesis, Università di Catania, 2018. http://hdl.handle.net/10761/4187.
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Since cities are responsible for the 67% of the world s energy demand and are the major contributors of CO2 emissions, governments and researchers push towards energy policy initiatives aiming at increasing the sustainability of urban areas. In this context, the diffusion of autonomous energy production systems on territory has been recognized as a cost-effective solution; moreover, their integration gives to consumers the possibility to exchange their own produced energy. This permits to configure a network of energy interactions among prosumers , i.e. consumers with production capabilities. In order to design the optimal energy distribution network among prosumers and, the same time, minimize the energy supply from traditional power plants, a comprehensive and focused approach is introduced and developed in this paper. The presented model encompasses the frameworks of both complex networks theory and agent-based models to provide a suitable solution of the energy distribution problem. The study is conducted for static and dynamical scenarios and the theoretical simulations are then compared to a real case study.
Overall, the proposed model offers significant insights for the definition of proper urban action plans centered on the efficient usage of energy and favouring the exploitation of renewable energy, thus allowing urban planners to make reasoned investment decisions.
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Milhano, JoseÌ Guilherme Teixeira de Almeida. "Finite partonic distribution functions at small-x." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249563.
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Meredith, Shaun Lee. "Construction of a gridded energy analyzer for measurements of ion energy distribution in the versatile toroidal facility." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50545.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998.Includes bibliographical references (p. 80-82).
The Versatile Toroidal Facility (VTF) at MIT's Plasma Science and Fusion Center provides a laboratory environment for studying ionospheric plasmas. Various plasma diagnostic devices have been created and used to study the VTF plasma since 1991. An accurate method for measuring VTF's ion characteristics has never been designed or installed in the laboratory facility. Gridded Energy Analyzers (GEA) are useful diagnostic tools for determining plasma ion energy distributions and ion temperature. Research was done on the theory behind Gridded Energy Analyzers and their applicability for use in the Versatile Toroidal Facility. A design and method for constructing a miniaturized GEA for VTF was developed and documented. The construction method covers material selection, machining, and assembly of VTF's miniature GEA. The miniature GEA is a non-perturbing probe used in VTF's plasma, which is approximately 3 cm in diameter. The GEA was constructed and preliminary experimental data was obtained. From this data VTF's ion temperature was found to be approximately 8eV and an ion distribution function was determined to be roughly Maxwellian in nature.
by Shaun L. Meredith.
S.M.
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Azuatalam, Donald. "Technical and Economic Assessments of Electricity Distribution Networks with Active Customers." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/21791.
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With a deepening penetration of distributed energy resources (DERs), distribution network service providers (DNSP) in most jurisdictions are faced with the challenge of designing tariff structures that are reflective of forward-looking network capacity costs, while ensuring a non-discriminatory, secure and reliable network for all end-users. Nonetheless, most electricity users seek to minimise their energy expenditure by participating in demand response programs or by actively managing their energy use through a home energy management system. Thus, DNSPs need to send accurate price signals to customers if they must achieve the desired peak demand targets. However, with inefficient pricing in place, DNSP loss in revenue and unfair cost allocation between customers may result. This thesis aims to address these challenges through a systematic technical and economic assessment of distribution networks with DER-enabled customers. To begin, a review of the performance of the state-of-the-art energy management methods is done in view of practicality and computational requirements while critiquing the modelling assumptions of each method. Next, a techno-economic assessment of grid defection is performed, based on the trade-off between the reliability and the levelised cost of electricity of residential PV-battery systems. Afterwards, the techno-economic impacts of different network tariffs, on low voltage networks are evaluated considering grid-connected customers, under various PV-battery penetration levels. Lastly, a benchmark for measuring the cost-reflectivity of network tariffs using cooperative game theory is proposed, which fairly apportions network costs to several customers with minimal error and computational burden. In brief, this thesis provides tools and analyses to guide DNSPs in designing DER-specific network tariffs which better signals network cost drivers, thus fostering customer participation while improving the equity of network cost allocations even with high DER penetration levels.
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Helseth, Arild. "Modelling Reliability of Supply and Infrastructural Dependency in Energy Distribution Systems." Doctoral thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2151.
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This thesis presents methods and models for assessing reliability of supply and infrastructural dependency in energy distribution systems with multiple energy carriers. The three energy carriers of electric power, natural gas and district heating are considered.
Models and methods for assessing reliability of supply in electric power systems are well documented, frequently applied in the industry and continuously being subject to research and improvement. On the contrary, there are comparatively few examples of formal reliability assessment models and methods applied to natural gas and district heating systems. This work aims at contributing to bridge this gap, considering the structural, operational and physical similarities and differences between the systems. A method for evaluating the reliability of supply in natural gas distribution systems is presented, based on state-of-the-art reliability calculations from the electric power domain. Furthermore, a novel modelling approach incorporating pipeline storage in reliability evaluation of high-pressure natural gas pipeline systems is presented.
Parallel energy infrastructures depend on each other at different levels, two of which are addressed in this work. First, by introducing a second energy carrier in an area dominated by electric power, the type of energy end-uses served by the electric power system is affected. An optimisation problem is formulated, finding the optimal allocation of switchgear in an electric power distribution system. It is shown how changes in energy end-uses cause changes in the expected customer interruption costs, which in turn affects the optimisation problem. Second, the dependency of district heating systems on electric power is modelled. Network models for the two systems are coupled, and the consequences of higher-order power system failures are quantified for both systems.
The methods and approaches presented in this thesis are demonstrated by use of simple examples, and applied to test networks and case studies.
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Gegužis, Ramūnas. "Impact of flow energy distribution on the ecological status of rivers." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2013~D_20131218_133501-16390.
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The aim of the study - to investigate interaction regularities of water flow energy distribution and stream beds during the naturalization process, to identify morphometric changes in the beds of streams and to assess the impact of these factors on the ecological status of rivers. To achieving this aim, 6 specific tasks were identified: 1 Designing geostatistical models of hydromorphological characteristics of regulated and natural river beds based on the field research results; 2 Identifying morphometric characteristics of river beds based on geostatistical models; 3 Determining regularities of the flow energy distribution and its interaction with the stream bed; 4 Determining the abundance and composition of grass and woody vegetation in the investigated sections of streams; 5 Determining the diversity, composition and abundance of macrozoobenthos and fish species; 6 Identifying the impact of flow energy distribution and stream bed interaction on the ecological status of rivers.Darbo tikslas – ištirti vandens tėkmės energijos pasiskirstymo ir upelių vagų sąveikos dėsningumus, vykstant natūralizacijos procesams, nustatyti morfometrinius pokyčius upelių vagose lemiančius veiksnius ir įvertinti jų poveikį upių ekologinei būklei. Darbo tikslui pasiekti buvo sprendžiami 6 uždaviniai: 1) taikant natūrinių tyrimų rezultatus, sudaryti geostatistinius reguliuotų ir natūralių vagų hidromorfologinių charakteristikų modelius; 2) pasinaudojus gautais modeliais, nustatyti morfometrines vagų charakteristikas; 3) pasinaudojus gautais modeliais, išsiaiškinti tėkmės energijos pasiskirstymo ir jos sąveikos su upelių vaga dėsningumus; 4) ištirti žolinės ir sumedėjusios augalijos gausą ir jos sudėtį tiriamų upelių atkarpose; 5) nustatyti makrozoobentoso ir juo besimaitinančių žuvų rūšinę įvairovę, sudėtį ir gausą; 6) išsiaiškinti tėkmės energijos pasiskirstymo ir upelių vagų sąveikos įtaką upių ekologinei būklei.
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CALILI, RODRIGO FLORA. "SYSTEM DEVELOPMENT TO DETECT COMMERCIAL LOSSES IN ELECTRICAL ENERGY DISTRIBUTION NETWORK." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7629@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOROs modelos matemáticos comumente usados na identificação de irregularidades na medição se baseiam na análise da redução percentual do consumo do mês (normalmente de 20% a 30%) em relação aos meses anteriores. Este método tem gerado resultados imprecisos uma vez que considera o valor do consumo como um valor rígido e, portanto, não incorpora o efeito da sazonalidade na tipologia das cargas das unidades consumidoras. Este trabalho tem o intuito de melhorar a identificação de clientes fraudulentos utilizando métodos de inteligência artificial, tais como Redes Neurais e Lógica Fuzzy, implementados a um banco de dados de cadastro da Distribuidora de Energia ELEKTRO e a uma Pesquisa de Posses e Hábitos de Consumo (PPH) feita nesta mesma empresa. Nesta dissertação, o objetivo foi classificar um grupo de consumidores como normal (adimplente), inadimplente e fraudulento. Para tanto, foi feita inicialmente uma clusterização utilizando uma Rede Neural, mais especificamente uma Rede de Kohonen, para o banco de dados de cadastro disponibilizado pela distribuidora. Tomando os grupos desta classificação prévia feita pela Rede identificaram-se quais e quantos destes tiveram PPH´s realizadas. Para se ter a classificação de um grupo quanto a incidência de consumidores normais, inadimplentes e fraudulentos utilizou-se um processo de Análise Fuzzy, o qual identifica os clusters com os consumidores de cada um dos segmentos. É feita uma análise de desempenho do modelo proposto com dados reais fornecidos pela empresa, na qual os resultados apontaram para uma robustez do método.
Mathematical models commonly used to identify irregularities in measurement are based on percentile reduction analysis of the monthly consumption (normally from 20% to 30%) in relation to the previous months. This method tends to generate imprecise results, since it considers the value of the consumption as a rigid value and, therefore, it does not incorporate the seasonal effect in the loads topology of the consumer units. This work has intention to improve the identification of fraudulent customers using artificial intelligence methods, such as Neural Networks and Fuzzy Logic, implemented to a database of consumers of ELEKTRO a distributing utility of São Paulo State, Brazil. It also uses information on appliances ownership obtained via market research in ELEKTRO area, named PPH (Portuguese for this particular type of market research). In this dissertation, the main objective was to classify a group of consumers as solvent, insolvent and fraudulent. In order to achieve this task, a clustering was initially made using a Neural Network framework, more specifically a Kohonen Network, for the database available. It was then checked which of the groups had a minimum number of clients interviewed in the PPH. In order to have the classification of the clients in the three categories it was used Fuzzy Analysis. Selected data is also presented, considering the available database of the Company as well as the research environment, which had been taken from the PPH. Finally, it was checked the performance of the method against real data obtained from the utility and the results were very satisfactory.
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GUIMARAES, ANDRE RESENDE. "CONTRACTING STRATEGIES IN ENERGY AUCTIONS FOR DISTRIBUTION COMPANIES UNDER DEMAND UNCERTAINTY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9137@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO objetivo desta dissertação de mestrado é analisar o novo marco regulatório do setor elétrico brasileiro e seus impactos para as empresas distribuidoras de energia. Para isto, foi desenvolvida uma ferramenta computacional para elaborar estratégias de atuação das distribuidoras nos leilões de compra de energia instituídos pela nova regulamentação. Desta forma, é possível simular o processo de contratação das distribuidoras no âmbito do ACR e, com os resultados, realizar análises do impacto das novas regras na alocação dos riscos as distribuidoras. O problema consiste, em um ambiente de incerteza da demanda e dado um conjunto de instrumentos de risco, determinar a estratégia de contratação das distribuidoras, fornecendo o montante de energia a ser comprado em cada leilão anteriormente descrito e resultado da melhor compra dados os contratos candidatos. A metodologia de solução é otimização estocástica multi-estágio, levando em consideração, principalmente, os diversos horizontes de contratação e preços da energia, visando minimizar uma ponderação entre tarifa para consumidor e custos para distribuidora.
The objective of this work is to analyze the new regulatory framework of the Brazilian electric sector. In this sense, it was developed a computational tool in order to elaborate strategies for the distribution companies (DISCOs) in the energy auctions instituted by the new regulation. The computational tool was used to simulate the contracts acquisition process by the DISCOs and the results were analyzed to measure impact of new rules and risks allocation for the distribution companies. The problem consists, considering the demand uncertainty and the available risk management instruments, in determining the contracting strategy of the DISCOs, i.e., the amount of energy to be bought in each auction that results from the best purchase given the candidate contracts. The solution methodology is based on a multi-stage stochastic optimization algorithm, minimizing the tariff for consumer and costs for DISCO, taking into account different prices and horizons of the energy contracts.
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Menke, Ruben. "Sustainable energy management of water distribution systems through optimised pump scheduling." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/50157.
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Climate change, caused by anthropogenic greenhouse gas emissions, is one of the most important issues of our time. It is often overlooked that up to 5% of a cities electrical energy consumption is required to pump water in the water distribution system. This thesis describes how pump scheduling can contribute to a more sustainable energy management of water distribution systems. The analysis is enabled though a new convex formulation of the pump scheduling problem, which provides theoretical optimality bounds, a requirement for the comparison of different energy management strategies. The problem formulation is then expanded to include variable speed pumps. The first energy management method investigated is the provision of demand response to the grid by adapting pump operating schedules. Demand response from water distribution systems is shown to provide reserve energy at lower cost and with less than half of the greenhouse gas emissions 240gCO2e/kWh of the competing technologies. Installing variable speed pumps in a network is shown to increase the possible applications of demand response and increase the revenue potential. Next, the trade-offs between cost and emission reduction are analysed in a range of energy supply scenarios in the UK, in the current grid as well as possible future scenarios. It is found that greenhouse gas emission cost must rise significantly, above £100 t/CO2, before affecting scheduling decisions. Furthermore, it is shown that the pump utilisation rate, the share of time the pump operates, is key to profit from possible changes in the energy supply. Finally, the operating schedule of pumps powered in part by an on-site wind turbine is optimised. This analysis calculates the cost of uncertainty in the wind power forecast in renewable energy generation. A stochastic optimisation method is presented that reduces the cost of uncertainty.
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Apelfeld, Yan. "Depth discrimination of an acoustic source based on modal energy distribution." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38880.
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Thesis (S.M. in Ocean Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 150-151).
The new method of acoustic source depth discrimination in a shallow water environment is investigated. The investigation is concentrated mainly in 500Hz and 1kHz sources in the range-independent and range-dependent environments. Efficiency and robustness of the method is studied and suggestions for the method's optimization are provided. The results of many simulation cases are presented and discussed. The results suggest that for the sources of 500Hz and 1kHz the depth discrimination method can provide an accurate estimate of the target's type: surface or submerged. The method can be useful for applications for which exact depth location is unnecessary and a target's category estimate is sufficient. The method is based on the fact that the modal energy distribution changes in accordance with a source depth category. Guidelines to achieve correct results are developed and presented. Method stability and robustness are examined. The range-independent case results suggest existence of 'shadow' areas where the standard method may provide a misleading depth estimate. Alternative methods are suggested to overcome the problem. The range-dependent case results suggest relatively poor performances of the method for a downslope environment. However, the upslope case results show superior performances than even in the range-independent case.
by Yan Apelfeld.
S.M.in Ocean Engineering
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Ofosuhene, Patrick. "The energy goodness-of-fit test for the inverse Gaussian distribution." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1605273458669328.
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Kawaguchi, Toshihiro. "OPTICAL-TO-X-RAY SPECTRAL ENERGY DISTRIBUTION OF ACTIVE GALACTIC NUCLEI." 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/149978.
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Behnood, Aref. "Optimal Operation of Battery Energy Storage Systems in Radial Distribution Networks." Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-397113.
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In recent years, power systems are facing with various challenges arising from the increased share of renewable energy systems. Among all sections of power systems, distribution grids are affected the most since the majority of renewable energy sources are connected to distribution grids. As the penetration of Variable Energy Sources increases in electric grids, energy storage systems have become more influential. In this context, this thesis presents a new algorithm for the optimal operation of Battery Energy Storage Systems in distribution grids. The proposed algorithm aims to define the optimal operation of Battery Energy Storage Systems considering the network topology, the output power of Variable Energy Sources and the electricity prices from the one-day ahead electric market as well as real time control of the batteries through smart appliances. In order to do this, firstly a comprehensive study on the existing Optimal Power Flow methods is carried out. Then, AR-OPF which is a novel Optimal Power Flow method for radial distribution systems is presented and the required mathematical constraints, equations and parameters of Battery Energy Storage Systems for modelling in distribution systems are described. Then, the problem formulation and the proposed algorithm are discussed in detail. Further to energy storage as the main function of Battery Energy Storage Systems, the impact of the proposed method on other functions of Battery Energy Storage Systems such as voltage control, grid support and loss reduction will be investigated. In order to do so, the proposed algorithm is applied to the IEEE 34 node test system as a case study. This will be carried out through defining several different scenarios. Finally, a sensitivity analysis is performed on the size of the existing batteries and the electricity price. The thesis will be concluded by the findings and possible future works.
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Francisco, Francisco Gemo Albino. "Wave energy distribution across the Agulhas Bank, a source of renewable energy for a seawater pumped storage scheme." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/6585.
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Smith, Christiane Maria. "Articulating ecological injustices of nuclear energy." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/15160.
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Harms produced by nuclear energy include the accident risks of population displacement, deaths, cancers, genetic, teratogenetic (affecting embryo and foetus) and psycho-social effects; increased radiation exposure to workers, locals and future generations from nuclear plants, uranium mines and waste storage facilities; thermal and toxic tailings pollution from nuclear plants and uranium mines; and other unknown long-term effects of increasing levels of background radiation. Historically, most greens have opposed nuclear energy alongside nuclear weapons. Recently, however, significant green spokespeople have combined with industry and governments in emphasising the need for nuclear energy in response to climate change. Based upon my experiences in the struggle against the Hinkley C nuclear power plant in Somerset, UK, this thesis contests the dominant framings of the debate. I suggest that arguments for nuclear energy are made possible by reductive understandings of the issue making it difficult to apprehend the significance of harms reinforced by nuclear energy. Taking an ecological approach I show how dominant discourses presuppose a hierarchical separation of science/politics, reinforced by and reinforcing the separation of nature/culture. These hierarchical separations depoliticise and naturalise harms produced by both nuclear energy and dominant forms of social organisation. As a result, these harms are difficult to communicate and contest as relevant to the discussion of our common futures. In this thesis I argue that we might more effectively convey the significance of these harms if we articulate them as injustices. Building upon the theory and practice of justice and liberation struggles I develop a heuristic framework for articulating injustices based around three intersecting images of politics as distribution, recognition and representation. I suggest articulating injustices of nuclear energy as i) the deprivation of basic necessities due to unequal distributions of burdens as well as goods; ii) the disrespect for ecological integrity due to desire for control of inevitable unpredictability in interaction; and iii) the denial of multiple authorities through monopolisation of rational speech and action and disengaged forms of knowledge production. Expressing harms of nuclear energy by way of this three-fold articulation of injustices politicises nuclear energy, climate change, and the dominant forms of social organisation, opening these up to political contestation to more effectively take ‘all affected’ into account before we reconsider how we might live together.
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Jogenfors, Jonathan. "A Classical-Light Attack on Energy-Time Entangled Quantum Key Distribution, and Countermeasures." Licentiate thesis, Linköpings universitet, Informationskodning, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-114073.
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Quantum key distribution (QKD) is an application of quantum mechanics that allowstwo parties to communicate with perfect secrecy. Traditional QKD uses polarization of individual photons, but the development of energy-time entanglement could lead to QKD protocols robust against environmental effects. The security proofs of energy-time entangled QKD rely on a violation of the Bell inequality to certify the system as secure. This thesis shows that the Bell violation can be faked in energy-time entangled QKD protocols that involve a postselection step, such as Franson-based setups. Using pulsed and phase-modulated classical light, it is possible to circumvent the Bell test which allows for a local hidden-variable model to give the same predictions as the quantum-mechanical description. We show that this attack works experimentally and also how energy-time-entangled systems can be strengthened to avoid our attack.
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Cardoso, Inês Isabel Martins. "Proposta de modelo para rede de distribuição elétrica de alta e média tensão." Master's thesis, Instituto Superior de Economia e Gestão, 2020. http://hdl.handle.net/10400.5/21094.
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Mestrado em Gestão de Sistemas de InformaçãoAtualmente, as redes de distribuição de energia vivem uma grande mudança de paradigma, assente no desenvolvimento sustentável, no aparecimento de novas unidades de produção renováveis e na mudança de redes passivas tradicionais para redes ativas. Esta complexidade e incremento vai original um maior desafio na sua gestão, monotorização e eficiência. Por essa razão, é necessário encontrar novas ferramentas que permitam ajudar no estudo e análise das redes de distribuição. Neste contexto, o projeto realizado aborda a construção e o desenvolvimento de um modelo de dados que simule a topologia da rede de distribuição elétrica de alta e média tensão no formato de um grafo (i.e., conjunto de nós e arestas), e que posteriormente possa ser utilizado como uma camada de construção e suporte para a elaboração de use cases de analítica. De forma a atingir este objetivo, foi elaborado um modelo conceptual, três versões distintas do grafo e um conjunto de use cases de analítica relevantes para a visualização, estudo e análise da rede de distribuição. A construção do grafo e o desenvolvimento dos use cases analíticos teve por base informação proveniente de um operador de rede de distribuição (ORD).
Nowadays, energy distribution networks are undergoing a major paradigm shift, based on sustainable development, emergence of new renewable production units and shift from traditional passive networks to active networks. This complexity and increase will create a greater challenge in its management, monitoring and efficiency. For this reason, it is necessary to find new tools that can help in the study and analysis of distribution networks.In this context, the aim of this project is to construct and develop a data model that simulates the topological structure of high and medium voltage electrical distribution grid in the form of a graph (i.e., a set of nodes and edges) and use it as a construction and support layer for the elaboration of analytical use cases. In order to achieve this objective, a conceptual model, three different versions of the graph and a set of analytical use cases relevant to the visualization, study and analysis of the distribution grid was developed. The construction of the graph and the development of the analytical use cases is based on information provided by a Distribution System Operator (DSO).
info:eu-repo/semantics/publishedVersion
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Högdahl, Sara. "Placing VOC Sensors forAssessing Air Quality : A CFD Study of Indoor VOC Distribution." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232347.
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The Swedish Obligatory Ventilation Control (OVK) was established to ensure that ventilation systemsare clean and work according to design. The control system of today is however not perfect, and thereare many aspects of OVK which could be approached differently for improved efficiency and occupanthealth. A current project in Stockholm is looking at the possibility to use sensors, continuouslymetering volatile organic compounds (VOC), temperature, and relative humidity, in place of the airflowmetering of the traditional OVK solution. One of the first issues encountered was sensor placement, asthe sensors must be discreetly installed on available surfaces while the collected air quality data mustrepresent the air in the occupied zone. A second challenge concerns how the sensor outputs should beinterpreted in terms of indoor air quality.The main purpose of this thesis is to suggest a model that can evaluate the suitability of differentplacements of sensors (such as the ceiling, walls, or lamp fixtures) from a VOC perspective. The idea isto evaluate what areas of the room best represent the average air quality of the occupied zone. This partof the study was approached by combining literature review and computational fluid dynamics (CFD)in two case studies; one office and one apartment. The intent behind the iterated method is to present ageneral CFD model that can be easily interpreted and adapted to accommodate new objects (e.g.building types or rooms). A secondary objective is to discuss how temperature and relative humiditycan be included in the spatial position evaluation. Thirdly, the thesis aims to develop a base for furtherdiscussion regarding a method for how the sensor outputs can be combined into a single indoorenvironment quality index. The two last parts were primarily based on literature review.The conclusions drawn in this study include a general CFD model that can be modified to evaluatedifferent spatial location of VOC sensors, and general guidelines regarding placement of VOC meters inoffices or apartments. Also provided in this report is a base for further discussion concerning indoor airquality estimations by combining the provided sensor-outputs, i.e. total VOC, temperature, and relativehumidity.Den obligatoriska ventilationskontrollen (OVK) infördes i Sverige för att säkerställa attventilationssystem är rena och fungerar som de är designade att göra. Dagens system är dock inteperfekt och det finns många aspekter av OVK som skulle kunna göras annorlunda för att främjaeffektivitet och personers hälsa. Ett pågående projekt i Stockholm vill undersöka möjligheten attersätta eller komplettera den luftflödesmätning som ingår i dagens OVK med kontinuerlig mätning avflyktiga organiska gaser (VOC), temperatur och relativ luftfuktighet med hjälp av sensorer. En av deförsta utmaningarna för projektet är placeringen av sensorer eftersom att de måste vara diskretinstallerade på befintliga ytor, samtidigt som det som uppmäts bör vara representativt för hur luftenupplevs av personer i byggnaden. En annan utmaning för projektet är hur signalerna från sensorn skakombineras för att utvärdera luftkvalitén.Det huvudsakliga syftet med den här studien är att utveckla en modell som kan användas för attutvärdera lämpligheten av olika sensorplaceringar, till exempel tak, väggar och lamparmaturer, utifrånett VOC-perspektiv. Idén är att ge en uppfattning om vilka placeringar som bäst representerarmedelkvalitén på luften i vistelsezonen. Denna del av arbetet baserades på litteraturstudier ochnumeriska beräkningar med CFD (Computational Fluid Dynamics). Den föreslagna modellenapplicerades i två fallstudier, ett kontor och en lägenhet. Avsikten med modellen är att den enkelt skakunna tolkas och anpassas för olika rumstyper. Ett annat syfte med rapporten är att diskutera hurtemperatur och relativ luftfuktighet kan inkluderas i utvärderingen av sensorplacering. Slutligen är etttredje syfte med studien att påbörja en diskussion för hur de tre mätvärdena från sensorn kankombineras i ett gemensamt inomhusklimatindex. De två sistnämnda delarna baserades främst pålitteraturstudier.Slutsatserna inkluderar en generell CFD-modell och metod som kan modifieras för att utvärdera olikaplaceringar av sensorn, samt riktlinjer för var VOC-sensorer bör placeras i kontor eller lägenheterbaserat på två fallstudier. Också inkluderade i rapporten är en diskussionsbas för hur en utvärdering avluftkvalitet kan göras utifrån de tre värdena från sensorn (VOC, temperatur och relativ luftfuktighet).
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Janigian, Darren. "Plug-In Hybrid Electric Vehicle Impacts on a Central California Residential Distribution Circuit." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/513.
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The adoption of plug-in hybrid electric vehicles (PHEV) as a means of transportation over conventionally fueled vehicles introduces new challenges to the existing infrastructure of the electrical transmission and distribution system. PHEV battery charging can represent a significant power demand that has the potential to overload electrical distribution components. This study examines the impacts of PHEV charging on household service transformers, distribution conductors and voltage levels of a Central California residential distribution system. The system is simulated using ETAP power system analysis software. Transformers are the most vulnerable to overloads, especially if PHEV charging occurs in clusters. Main feeder conductors will be overloaded if a large amount of high power, quick charging occurs. Branch conductors will not be affected by PHEV charging. Based on current PHEV market projections for the region this study shows that significant equipment overloads are not likely to occur until well after 2017.
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Dimobi, Ikechukwu Samuel. "Transactive Distribution Grid with Microgrids Using Blockchain Technology for the Energy Internet." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/102216.
Full textAbstract:
The changing nature of the energy grid in recent years has prompted key stakeholders to think of ways to address incoming challenges. Transactive energy is an approach that promises to dynamically align active grid elements coming up in the previously inactive consumers' side to achieve a reliable and smarter grid. This work models the distribution grid structure as a combination of microgrids. A blockchain-in-the loop simulation framework is modelled and simulated for a residential microgrid using power system simulators and transactive agents. Blockchain smart contracts are used to coordinate peer-to-peer energy transactions in the microgrid. The model is used to test three market coordination schemes: a simple auction-less scheme, an auction-less scheme with a normalized sorting metric and an hour ahead single auction scheme with penalties for unfulfilled bids. Case studies are presented of a microgrid with 30 homes, at different levels of solar and energy storage penetration within the microgrid, all equipped with responsive and unresponsive appliances and transactive agents for the HVAC systems. The auction-less scheme with a normalized sorting metric is observed to provide a fairer advantage to smaller solar installations in comparison to the simple auction-less method. It is then concluded that the auction-less schemes are most beneficial to users, as they would not need sophisticated forecasting technology to reduce penalties from bid quantity inaccuracies, as long as the energy mix within the microgrid is diverse enough.Master of Science
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Nouri, Hassan. "Erosion and electrode energy distribution in switches with silver-cadmium-oxide contacts." Thesis, University of Plymouth, 1990. http://hdl.handle.net/10026.1/2391.
Full textAbstract:
The cathode and the anode fall of the DC arcs are measured by fast oscilloscope for Ag-CdO contacts over a range of gap-lengths from 0.05 mm to 1 mm, and currents of 4-10 Amps at atmospheric pressure, with a known electrode closing speed, using the Moving Electrode Method. It was observed that the anode fall can occur in a few places within the arc voltage waveform, and is dependent of the electrodes' surface condition. Both cathode and anode falls increase with gap-length and decrease with current. It was found that when arc length is shorter than electrode separation, discontinuity within the arc voltage waveform during closure is caused, in many cases, by vapourisation of the first point of contact or by a high electric field set up between the two electrodes. These discontinuities are named as Voltage Step Phenomena. These voltage steps are related to the cathode and anode fall voltages, and their regular occurrences are a function of surface roughness. The fluctuations in the arc voltage waveform are thought to originate mainly from the cathode. A technique has been developed to measure the temperature of the electrodes accurately by using a T-type thermocouple, 0.075 mm diameter, in conjunction with a DC amplifier with a gain of 247. The thermocouple is placed as close as possible under the electrode surface (200 µm). This enables the temperature of the contact to be measured, after breaking contact, for an arc-duration even as short as 1ms. The time-constant of the probe (contact containing the thermocouple) is measured to be approximately 18ms. With this technique the temperature of the electrodes are measured for currents and gap-lengths ranging 4-10 Amps and 0.05-1 mm respectively. The effect of contacts being new and change of polarity have been investigated. From these results it is concluded that the co-existence of layers of foreign material on one, or both, surfaces causes the temperature of the electrodes to be high for the first 50-100 operations, before reaching to steady-state conditions. Change of polarity suggests that the moving electrode, either anode or cathode, due to the effect of air movement over its surface, is cooled relative to when fixed. The power transfer to the electrodes is calculated for various currents and gap-length using thermal analogue formulae derived from the transient response of an RC circuit to a d.c. pulse. The results show that below 0.2 mm the sum of the anode and cathode power is approximately equal to the arc power, and hence losses are negligible. At around 0.125 mm, for currents of about 6A and 12A, they both receive an equal amount of power from the arc. This has been related to the thermal energy of the electrons being negligible, at such separation, at the anode end of the plasma column. The power balance equations are solved to calculate the positive ion current to the cathode, and the thermal energy of the electrons in the plasma column, under various test conditions. In the investigation of erosion, the S.E.M. studies show that most of the power dissipated on the surface of the electrodes is used in melting and evaporation. The x-ray analysis shows that the melted metal is composed mostly of Silver. To operate the test rig and collect the generated data automatically, a computerised test system, with a mini data acquisition system, has been designed and constructed here.
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SILVA, LEANDRO BISPO DA. "METHODOLOGY TO OPTIMIZATION OF ENERGY AUCTIONS CONTRACTS TO A COMPANY OF DISTRIBUTION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=12363@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCom o novo modelo do setor elétrico implantado no início desta década, vários desafios foram impostos aos agentes dessa área. Para os agentes de distribuição, o modelo implica em procurar otimizar processos, sempre mantendo certo nível de qualidade dos serviços, monitorado pelo agente regulador. Uma das obrigações das distribuidoras é a contratação adequada de energia para fornecimento de seus clientes considerando períodos futuros. O presente trabalho tem por objetivo desenvolver uma estratégia de apoio às decisões de uma distribuidora de energia para a contratação em leilões de energia elétrica. O método contempla uma etapa de previsão de consumo de energia num horizonte de cinco anos, e a partir dos valores estimados e de outros componentes formadores dos custos de contratação, como o Valor de Referência Anual e o Preço de Liquidação de Diferenças, realiza simulações de cenários, que visam propiciar uma otimização na formação da carteira de contratos. Ao final são definidos os percentuais ótimos de contratação, que garantam o atendimento completo ao mercado cativo da distribuidora, e que minimizam os riscos de aplicações de penalidades por sub ou sobrecontratação.
The implementation of the new model for the electrical sector in Brazil resulted in big challenges to the agents involves in this market. For the distributing utilities agents, in particular, the model somehow requires an optimization of all their processes but, at the same time, keeping the quality of the services supplied to their clients within the level stated by the regulator. Among these challenges, the distributing utilities, within the new model, have to perform the correct acquisition of energy from the supply utilities for future periods (up to 5 years ahead). This thesis aims to provide tools to help a distributing utility on the decision of energy acquisition on the electrical energy auctions. The approach includes a stage of energy consumption forecasts up to 5 - years - ahead and simulation stage where the demand forecasts and the energy prices series are the random variables implemented in a simulation scheme that generates possible energy acquisition scenarios. At the end, the optimal energy acquisition are obtained in such a way that the captive utility is fully contracted for the next five years where the utility penalties for under or over acquisition are minimized.
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Zhang, Tan. "The Economic Benefits of Battery Energy Storage System in Electric Distribution System." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/298.
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The goal of this study was to determine the economic feasibility of battery energy storage system (BESS). Three major economic benefits derived from BESS using were studied: 1. Energy Purchase Shifting, 2. Distribution Feeder Deferral, 3. Outage Avoidance. The economic analysis was based on theoretical modeling of the BESS and distribution system. Three simulation models were developed to quantify the effects of different parameters, such as: BESS round-trip efficiency, life span, rated power, rated discharge time, marginal cost of electric energy, 24 h feeder load profile, annual load variation, feeder load growth rate and feeder length. An optimal battery charging/discharging method was presented to determine the differential cost of energy (DCE). The annual maximum DCE was calculated using stochastic probability analysis on seasonal load variation. The net present value was evaluated as the present value difference between two investments: first, the distribution feeder upgrade without BESS deferral, and second, with BESS deferral. Furthermore, the BESS’s contributions under different outage strategies were compared. It was determined that feeder length is the most significant parameter. The economics of the studied system becomes favorable when the feeder length exceeds a critical value.
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Wei, Quantum Jichi. "Two-stage reverse osmosis : optimal element configuration and flux distribution, energy savings." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111900.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 57-59).
In a two-stage reverse osmosis (RO) system of finite size, there are two degrees of freedom not present in a single-stage RO system: distribution of RO elements between the two stages (system design), and feed pressures (system operation). In this study, we investigate the optimal system design and operation of a two-stage RO system with a mass-balance model and establish a lower bound for the energy savings achieved by the optimized two-stage system compared to a single-stage system. A two-stage RO system may consume more or less energy than a single-stage RO system of the same size and freshwater productivity, depending on the first-stage feed pressure and second-stage feed pressure. To minimize energy consumption, feed pressures should be chosen to minimize spatial variance in flux. The optimal element configuration places at least half the elements in the first stage; the exact configuration depends on feed salinity, recovery ratio, and membrane permeability. The greatest energy savings are achieved with a two-stage RO system that has both optimal element configuration and feed pressures. More energy can be saved by adding a stage when the thermodynamic least work of separation is larger. For a given feed salinity, energy savings from adding a second stage grow as recovery ratio increases. Brackish water feeds must be taken to high recovery ratios to achieve substantial energy savings; comparable savings can be achieved at lower recovery ratios for higher salinity feeds. We find that significant energy can be saved with the simplest two-stage RO design, at a system flux similar to today's RO plants and accounting for the effects of concentration polarization.
by Quantum J. Wei.
S.M.
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Bulger, Daniel. "The high energy asymptotic distribution of the eigenvalues of the scattering matrix." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/the-high-energy-asymptotic-distribution-of-the-eigenvalues-of-the-scattering-matrix(541fc908-ff77-4f0f-b3ba-af1fe53e19dd).html.
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We determine the high energy asymptotic density of the eigenvalues of the scat- tering matrix associated with the operators H0 = −∆ and H = (i∇ + A)2 + V (x), where V : Rd → R is a smooth short-range real-valued electric potential and A = (A1, . . . , Ad) : Rd → Rd is a smooth short-range magnetic vector-potential. Two cases are considered. The first case is where the magnetic vector-potential is non-zero. The spectral density of the associated scattering matrix in this case is expressed as an integral solely in terms of the magnetic vector-potential A. The second case considered is where the magnetic vector-potential is identically zero. Again the spectral density of the scattering matrix is expressed as an integral, this time in terms of the poten- tial V . These results share similar characteristics to results pertaining to semiclassical asymptotics for pseudodifferential operators.