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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Planejamento agregado em redes de distribuição secundária - modelo alternativo para empresas com cadastro de redes reduzido. / Investments planning in low voltage distribution networks - alternative model for companies with reduced database.

Squaiella, Davi José Ferreira 08 March 2004 (has links)
As redes secundárias de distribuição são item de extrema importância no processo de levar a energia produzida de uma fonte até o consumidor final. Dentro de uma Empresa Concessionária de Distribuição de Energia Elétrica o setor de planejamento, juntamente com o grupo técnico, deve realizar o planejamento dos investimentos necessários nos níveis de alta, média e baixa tensão, sendo que para a baixa tensão (redes secundárias de distribuição), normalmente utilizam-se os dados históricos e a média de investimentos dos últimos anos (de três a cinco últimos anos). Em geral não são encontrados nestas Empresas os cadastramentos das redes secundárias de distribuição ou então, quando estes existem, muitas vezes não são confiáveis. Neste ponto, esta dissertação de mestrado apresentará, aplicará e discutirá os resultados de uma metodologia de geração de redes secundárias de distribuição a partir dos dados das redes primárias de distribuição (média tensão) e dos ativos da Empresa, tendo como foco os investimentos necessários para estas dentro do planejamento agregado de investimentos. O trabalho proposto visa criar condições para que as Empresas enquadradas na situação anterior possam realizar o seu planejamento de baixa tensão valendo-se da aplicação de uma metodologia capaz de gerar tais redes. Uma vez criadas, tais redes serão inseridas dentro de um software de planejamento agregado de investimentos que fornecerá o valor total das aplicações necessárias para os próximos dez anos (planejamento decenal – longo prazo). Ao final do processo, poderá ser observado que os resultados obtidos são muito próximos dos valores esperados para as redes secundárias reais e, com isto, a dissertação discutirá como a metodologia foi implementada, os detalhes da aplicação e, até mesmo, todo o processo de planejamento para três Empresas Concessionárias de Distribuição de Energia Elétrica. Já de posse dos resultados, poderá afirmar-se que o processo produziu valores de muito boa aderência e, assim, os investimentos obtidos para as redes secundárias poderão ser aceitos pelo grupo de planejamento da Empresa. Como conseqüência dos valores de investimentos obtidos para os dez anos, poderão ser observados ainda, guardadas algumas considerações especiais, os valores dos custos marginais de baixa tensão, item de grande importância no planejamento de redes de distribuição. / The low voltage distribution networks are an item of extreme importance in the process of delivering the produced energy from a plant (supply) to the final consumer. In an Electric Power Distribution Company the planning group (sector), together with the technical group, must accomplish the planning of the necessary investments in the high voltage, medium voltage and low voltage levels, and for low voltage distribution networks, usually the historical data and the average of investments of the last years are used (from three to last five years). In general the databases of low voltage networks are not found in these Companies or then, when these exist, a lot of times they are not reliable. For this, this article will show, apply and discuss the results of a methodology for generating low voltage distribution networks starting from the database of the medium voltage distribution networks and of the assets of the Company, having as focus the necessary investments for these networks in planning of investments. The proposed work wishes to create conditions so that the Companies that are in the previous situation can accomplish their planning on low voltage distribution networks using a methodology capable to generate such nets. Once created, such nets will be inserted in a software of planning of investments that will supply the total amount of investments for them for the next ten years (long period planning). In the end of the process, it will be observed that the obtained results are very close to the expected values for the real low voltage distribution networks and, with this, the article will discuss how the methodology was implemented, the details of the application and, even, the whole planning process for three Electric Power Distribution Companies. With the results, it will be affirmed that the process produces values of very good adherence and, for this, the investments obtained for low voltage distribution networks can be accepted by the planning group in the Company. As a consequence of the investments values obtained for the ten years, it will be able to be observed, kept some special considerations, the values of the marginal costs of low voltage, item of great importance in the planning of distribution networks.
22

Planejamento agregado em redes de distribuição secundária - modelo alternativo para empresas com cadastro de redes reduzido. / Investments planning in low voltage distribution networks - alternative model for companies with reduced database.

Davi José Ferreira Squaiella 08 March 2004 (has links)
As redes secundárias de distribuição são item de extrema importância no processo de levar a energia produzida de uma fonte até o consumidor final. Dentro de uma Empresa Concessionária de Distribuição de Energia Elétrica o setor de planejamento, juntamente com o grupo técnico, deve realizar o planejamento dos investimentos necessários nos níveis de alta, média e baixa tensão, sendo que para a baixa tensão (redes secundárias de distribuição), normalmente utilizam-se os dados históricos e a média de investimentos dos últimos anos (de três a cinco últimos anos). Em geral não são encontrados nestas Empresas os cadastramentos das redes secundárias de distribuição ou então, quando estes existem, muitas vezes não são confiáveis. Neste ponto, esta dissertação de mestrado apresentará, aplicará e discutirá os resultados de uma metodologia de geração de redes secundárias de distribuição a partir dos dados das redes primárias de distribuição (média tensão) e dos ativos da Empresa, tendo como foco os investimentos necessários para estas dentro do planejamento agregado de investimentos. O trabalho proposto visa criar condições para que as Empresas enquadradas na situação anterior possam realizar o seu planejamento de baixa tensão valendo-se da aplicação de uma metodologia capaz de gerar tais redes. Uma vez criadas, tais redes serão inseridas dentro de um software de planejamento agregado de investimentos que fornecerá o valor total das aplicações necessárias para os próximos dez anos (planejamento decenal – longo prazo). Ao final do processo, poderá ser observado que os resultados obtidos são muito próximos dos valores esperados para as redes secundárias reais e, com isto, a dissertação discutirá como a metodologia foi implementada, os detalhes da aplicação e, até mesmo, todo o processo de planejamento para três Empresas Concessionárias de Distribuição de Energia Elétrica. Já de posse dos resultados, poderá afirmar-se que o processo produziu valores de muito boa aderência e, assim, os investimentos obtidos para as redes secundárias poderão ser aceitos pelo grupo de planejamento da Empresa. Como conseqüência dos valores de investimentos obtidos para os dez anos, poderão ser observados ainda, guardadas algumas considerações especiais, os valores dos custos marginais de baixa tensão, item de grande importância no planejamento de redes de distribuição. / The low voltage distribution networks are an item of extreme importance in the process of delivering the produced energy from a plant (supply) to the final consumer. In an Electric Power Distribution Company the planning group (sector), together with the technical group, must accomplish the planning of the necessary investments in the high voltage, medium voltage and low voltage levels, and for low voltage distribution networks, usually the historical data and the average of investments of the last years are used (from three to last five years). In general the databases of low voltage networks are not found in these Companies or then, when these exist, a lot of times they are not reliable. For this, this article will show, apply and discuss the results of a methodology for generating low voltage distribution networks starting from the database of the medium voltage distribution networks and of the assets of the Company, having as focus the necessary investments for these networks in planning of investments. The proposed work wishes to create conditions so that the Companies that are in the previous situation can accomplish their planning on low voltage distribution networks using a methodology capable to generate such nets. Once created, such nets will be inserted in a software of planning of investments that will supply the total amount of investments for them for the next ten years (long period planning). In the end of the process, it will be observed that the obtained results are very close to the expected values for the real low voltage distribution networks and, with this, the article will discuss how the methodology was implemented, the details of the application and, even, the whole planning process for three Electric Power Distribution Companies. With the results, it will be affirmed that the process produces values of very good adherence and, for this, the investments obtained for low voltage distribution networks can be accepted by the planning group in the Company. As a consequence of the investments values obtained for the ten years, it will be able to be observed, kept some special considerations, the values of the marginal costs of low voltage, item of great importance in the planning of distribution networks.
23

Návrh rozvoje a řešení konfigurace sítě 22 kV / Distribution Network Development and Configuration

Pospíšil, Petr January 2010 (has links)
The theme of this master‘s thesis is distribution network development and configuration in the part of Brno – Trnitá. There is expected to be investments there in the next few years. The thesis consists of two parts. For better understanding of this problem, the first theoretical part concerns with the description of electrical network (subdivision in accordance with voltage levels, conductor types, network types and other electrical network parts), solution of grid’s steady state (as a linear task and also non-linear task, elimination of the balancing node, the iterative method) and Brno distribution network characteristics. The second part concerns with distribution network development and configuration depending on anticipated load development in Trnitá. The result is proposal for transformer station construction Opuštěná fitted with three transformers of nominal output SN = 40 MVA and network configuration change required both for providing new consumption supply as well as sustaining current one.
24

Multi-Agent Based Fault Localizationand Isolation in Active DistributionNetworks

Chaitanya, Deshpande January 2015 (has links)
Liberalized electricity markets, increased awareness of clean energy resources and theirdecreasing costs have resulted in large numbers of distributed power generators beinginstalled on distribution network. Installation of distributed generation has altered thepassive nature of distribution grid. A concept of Active Distribution Network is proposedwhich will enable present day infrastructure to host renewable energy resources reliably.Fault management that includes fault localization, isolation and service restoration ispart of active management of distribution networks.This thesis aims to introduce a distributed protection methodology for fault localizationand isolation. The objective is to enhance reliability of the network. Faults are identifiedbased on root mean square values of current measurements and by comparing thesevalues with preset thresholds. The method based on multi-agent concept can be usedto locate the faulty section of a distribution network and for selection of faulty phases.The nodal Bus Agent controls breakers that are associated with it. Based on indicationof fault, adjacent bus Agents communicate with each other to identify location of fault.A trip signal is then issued to corresponding Breakers in adjacent Bus Agents, isolatingthe faulty section of line. A case study was carried out to verify suitability of the proposedmethod. A meshed network model and multi-agent based protection scheme wassimulated in Simulink SimPowerSystems. Considering nature of Distribution Network,separate breakers for each phase are considered. The distribution network protectionsystem identified fault introduced in the network correctly along with interrupting thefault current.Keywords
25

Effects of load shifting on water quality in a large potable water network / Francois Gysbert Jansen van Rensburg

Jansen van Rensburg, Francois Gysbert January 2015 (has links)
Mathematical analyses indicated that significant possibilities exist for load shifting projects on a Large Potable Water Utility (LPWU) in South Africa. A primary concern remained, i.e. whether the load variation would have an effect on the water quality. Extensive simulation and testing were initiated in order to prove that the load shift will not affect the water quality. In South Africa, the highest standard for drinking water is the Blue Drop award. The LPWU has received this award multiple times and strives to maintain it. An investigation was launched to determine if this load shifting project would have an effect on the quality standards to which the utility holds (SANS 241 (2011)). The LPWU has over 3000 km of pipelines to supply potable water to the industrial heartland of the country as well as millions of domestic users. The LPWU network is the longest pumping network in the world and is still expanding. The investigation included a simulation of a pumping simulation package to determine how the system would react to the changes. In this simulation, the load reduction in terms of Mega litre per day (Ml/day) was established. Results were compared to the normal operating parameters of the Water Treatment Works (WTW). The mathematical analysis in this investigation concluded that an evening peak load shift of 24.5 MW is achievable. This dissertation will emphasise the necessity of a detailed investigation. The investigations and simulation will determine that the volume of water is well within the operating parameters of the WTW. Studies were done on each area of the plant. In-depth conversations with WTW personnel revealed that the reduction of the volume of water in question will not have an effect on the water quality. Further, it was established that it would be possible to use the sumps of the water treatment works to achieve the desired load shift. By using the sumps of the WTW, a load shift can be done without stopping any process in the WTW with the exception of disinfection at the Booster Pump Stations (BPS), where the balancing reservoirs were used as buffer capacity. The investigation shifted to establish whether stagnant water and a change in dosage would have an effect on the water quality in regard to the reduction and recovery load. As expected, the water never became stagnant at any moment due to the fact that only a small portion of the load was reduced. The water quality and dosage report of the water utility was used and compared to normal operations. The planned load shift had no effect on any aspects of the water quality. The project is feasible and will reach the set targets without affecting the water quality. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
26

Effects of load shifting on water quality in a large potable water network / Francois Gysbert Jansen van Rensburg

Jansen van Rensburg, Francois Gysbert January 2015 (has links)
Mathematical analyses indicated that significant possibilities exist for load shifting projects on a Large Potable Water Utility (LPWU) in South Africa. A primary concern remained, i.e. whether the load variation would have an effect on the water quality. Extensive simulation and testing were initiated in order to prove that the load shift will not affect the water quality. In South Africa, the highest standard for drinking water is the Blue Drop award. The LPWU has received this award multiple times and strives to maintain it. An investigation was launched to determine if this load shifting project would have an effect on the quality standards to which the utility holds (SANS 241 (2011)). The LPWU has over 3000 km of pipelines to supply potable water to the industrial heartland of the country as well as millions of domestic users. The LPWU network is the longest pumping network in the world and is still expanding. The investigation included a simulation of a pumping simulation package to determine how the system would react to the changes. In this simulation, the load reduction in terms of Mega litre per day (Ml/day) was established. Results were compared to the normal operating parameters of the Water Treatment Works (WTW). The mathematical analysis in this investigation concluded that an evening peak load shift of 24.5 MW is achievable. This dissertation will emphasise the necessity of a detailed investigation. The investigations and simulation will determine that the volume of water is well within the operating parameters of the WTW. Studies were done on each area of the plant. In-depth conversations with WTW personnel revealed that the reduction of the volume of water in question will not have an effect on the water quality. Further, it was established that it would be possible to use the sumps of the water treatment works to achieve the desired load shift. By using the sumps of the WTW, a load shift can be done without stopping any process in the WTW with the exception of disinfection at the Booster Pump Stations (BPS), where the balancing reservoirs were used as buffer capacity. The investigation shifted to establish whether stagnant water and a change in dosage would have an effect on the water quality in regard to the reduction and recovery load. As expected, the water never became stagnant at any moment due to the fact that only a small portion of the load was reduced. The water quality and dosage report of the water utility was used and compared to normal operations. The planned load shift had no effect on any aspects of the water quality. The project is feasible and will reach the set targets without affecting the water quality. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
27

Multi-objective hyper-heuristics and their application to water distribution network design

McClymont, Kent January 2012 (has links)
Hyper-heuristics is a new field of optimisation which has recently emerged and is receiving growing exposure in the research community and literature. Hyper-heuristics are optimisation methods which are designed with a high level of abstraction from any one specific problem or class of problems and therefore are more generally applicable than specialised meta-heuristic and heuristic methods. Instead of being designed to solve a specific real-world problem, hyper-heuristics are designed to solve the problem of heuristic generation and selection. As such, hyper-heuristics can be thought of as methods for optimising the operations of an optimisation process which finds good solutions to a problem as a by-product. This approach has been shown to be very effective and in some cases provides improvement in search performance as well as reducing the burden associated with tailoring meta-heuristics which is often required when solving new problems. In this thesis, the hypothesis that hyper-heuristics can be competitively applied to real-world multi-objective optimisation problems such as the water distribution design problem is tested. Although many single-objective hyper-heuristics have been proposed in the literature, only a few multi-objective methods have been proposed. This thesis explores two different novel multi-objective hyper-heuristics: one designed for generating new specialised heuristics; and one designed for solving the online selection of heuristics. Firstly, the behaviour of a set of heuristics is explored to create a base understanding of different heuristic behavioural traits in order to better understand the hyper-heuristic behaviours and dynamics later in the study. Both approaches are tested on a range of benchmark optimisation problems and finally applied to real-world instances of the water distribution network design problem where the selective hyper-heuristics is demonstrated as being very effective at solving this difficult problem. Furthermore, the thesis demonstrates how heuristic selection can be improved by incorporating a greater level of information about heuristic performance, namely the historical joint performance of different heuristics, and shows that exploiting this sequencing information in heuristic selection can produce highly competitive results.
28

Power distribution network modeling and microfluidic cooling for high-performance computing systems

Zheng, Li 07 January 2016 (has links)
A silicon interposer platform with microfluidic cooling is proposed for high-performance computing systems. The key components and technologies for the proposed platform, including electrical and fluidic microbumps, microfluidic vias and heat sinks, and simultaneous flip-chip bonding of the electrical and fluidic microbumps, are developed and demonstrated. Fine-pitch electrical microbumps of 25 µm diameter and 50 µm pitch, fluidic vias of 100 µm diameter, and annular-shaped fluidic microbumps of 150 µm inner diameter and 210 µm outer diameter were fabricated and bonded. Electrical and fluidic tests were conducted to verify the bonding results. Moreover, the thermal and signaling benefits of the proposed platform were evaluated based on thermal measurements and simulations, and signaling simulations. Compared to the conventional air cooling, significant reductions in system temperature and thermal coupling are achieved with the proposed platform. Moreover, the signaling performance is improved due to the reduced temperature, especially for long interconnects on the silicon interposer. A numerical power distribution network (PDN) simulator is developed based on distributed circuit models for on-die power/ground grids, package- and board- level power/ground planes, and the finite difference method. The simulator enables power supply noise simulation, including IR-drop and simultaneous switching noise, for a full chip with multiple blocks of different power, decoupling capacitor, and power/ground pad densities. The distributed circuit model is further extended to include TSVs to enable simulations for 3D PDN. The integration of package- and board- level power/ground planes enables co-simulation of die-package-board PDN and exploration of new PDN configurations.
29

Development of Test Equipment for Analysis of Camera Vision Systems Used in Car Industry : Printed Ciruit Board Design and Power Distribution Network Stability

Johansson, Jimmy, Odén, Martin January 2015 (has links)
The main purpose of this thesis was to develop a printed circuit board for Autoliv Electronics AB. This circuit board should be placed in their test equipment to support some of their camera vision systems used in cars. The main task was to combine the existing hardware into one module. To be able to achieve this, the most important factors in designing a printed circuit board was considered. A satisfying power distribution network is the most crucial one. This was accomplished by using decoupling capacitors to achieve low enough impedance for all circuits. Calculations and simulations were executed for all integrated circuits to find the correct size and numbers of capacitors. The impedance of the circuit board was tested with a network analyzer to confirm that the impedance were low enough, which was the case. System functionality was never tested completely, due to delivery problems with some external equipment.
30

A Time-Evolving Optimization Model for an Intermodal Distribution Supply Chain Network:!A Case Study at a Healthcare Company

Johansson, Sara, Westberg, My January 2016 (has links)
Enticed by the promise of larger sales and better access to customers, consumer goods compa- nies (CGCs) are increasingly looking to evade traditional retailers and reach their customers directly–with direct-to-customer (DTC) policy. DTC trend has emerged to have major im- pact on logistics operations and distribution channels. It oers significant opportunities for CGCs and wholesale brands to better control their supply chain network by circumventing the middlemen or retailers. However, to do so, CGCs may need to develop their omni-channel strategies and fortify their supply chains parameters, such as fulfillment, inventory flow, and goods distribution. This may give rise to changes in the supply chain network at all strategic, tactical and operational levels. Motivated by recent interests in DTC trend, this master thesis considers the time-evolving supply chain system of an international healthcare company with preordained configuration. The input is bottleneck part of the company’s distribution network and involves 20% ≠ 25% of its total market. A mixed-integer linear programming (MILP) multiperiod optimization model is developed aiming to make tactical decisions for designing the distribution network, or more specifically, for determining the best strategy for distributing the products from manufacturing plant to primary distribution center and/or regional distribution centers and from them to customers. The company has got one manufacturing site (Mfg), one primary distribution center (PDP) and three dierent regional distribution centers (RDPs) worldwide, and the customers can be supplied from dierent plants with various transportation modes on dierent costs and lead times. The company’s motivation is to investigate the possibility of reduction in distribution costs by in-time supplying most of their demand directly from the plants. The model selects the best option for each customer by making trade-os among criteria involving distribution costs and lead times. Due to the seasonal variability and to account the market fluctuability, the model considers the full time horizon of one year. The model is analyzed and developed step by step, and its functionality is demonstrated by conducting experiments on the distribution network from our case study. In addition, the case study distribution network topology is utilized to create random instances with random parameters and the model is also evaluated on these instances. The computational experiments on instances show that the model finds good quality solutions, and demonstrate that significant cost reduction and modality improvement can be achieved in the distribution network. Using one-year actual data, it has been shown that the ratio of direct shipments could substantially improve. However, there may be many factors that can impact the results, such as short-term decisions at operational level (like scheduling) as well as demand fluctuability, taxes, business rules etc. Based on the results and managerial considerations, some possible extensions and final recommendations for distribution chain are oered. Furthermore, an extensive sensitivity analysis is conducted to show the eect of the model’s parameters on its performance. The sensitivity analysis employs a set of data from our case study and randomly generated data to highlight certain features of the model and provide some insights regarding its behaviour.

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