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CFD investigation for turbidity spikes in drinking water distribution networksHossain, Alamgir, n/a January 2005 (has links)
Drinking water distribution networks such as South East Water Ltd. (SEWL), Melbourne Water, Sydney Water, etc. are supposed to transport only dissolved matter rather than a few visible particles. However, it is almost impossible to make the drinking water free from suspended solid particles. The ability to determine the origins of these particles varies between different water supply systems, with possible sources being from catchment, treatment processes, biofilm growth within the water supply pipes, and corrosion products. Improvement of our understanding of the complex hydrodynamic behavior of suspended and/or deposited particles involved in these distribution pipe networks requires mathematical and physical models. Computational Fluid Dynamics (CFD) along with analytical turbulent model is one of the most popular mathematical techniques, which has the ability to predict the behavior of complex flows for such multiphase flow applications.
This study has been completed mainly in two steps. A CFD investigation was carried out to predict the hydrodynamic behavior of turbid particle flowing through a horizontal pipe networks including loop consist of bends and straight pipes. Furthermore, an extended analytical model was re-developed for the liquid-solid system to look at the similar behavior of the solid particles flowing in a turbulent field. These two parallel studies will provide better understandings about the turbidity spikes movements in the distribution networks.
A comprehensive CFD investigation was carried out for particle deposition in a horizontal pipe loop consisting of four 900 bends in a turbulent flow field. A satisfactory agreement was established with the experimental data as validation. This was a steady state multi-particle problem, which helped to understand the deposition characteristics for different particle sizes and densities at upstream and downstream sides of the bends as well as its circumference. Particle concentration was seen high at the bottom wall in the pipe flow before entering the bends, but for the downstream of bend the deposition was not seen high at the bottom as seen in upstream of bend rather inner side of the bend wall (600 skewed from bottom). The larger particles clearly showed deposition near the bottom of the wall except downstream. As expected, the smaller particles showed less tendency of deposition and this was more pronounced at higher velocity. Due to the high stream line curvature and associated centrifugal force acting on the fluid at different depths the particles became well mixed and resulted in homogeneous distribution near the bend regions.
The hydrodynamic behavior of particles flowing in a turbulent unsteady state flowing through a horizontal pipe was also studied to compare with the drinking water distribution networks data. In this numerical simulation six different flow-profiles and particle-load profiles were used to compute particles deposition and re-entrainment into the systems and to identify the conditions of the deposition and suspension mechanisms. Results showed that after a certain length of pipe and period of time after downward velocity gradient, when the velocity was constants over time, the shear stress was sufficiently high enough to cause the particle deposition on and roll along the bottom wall of pipe wall and created a secondary group of particle peak (called kink).
Finally, an extended analytical Turbulent Diffusion Model for liquid-solid phase was developed following an existing gas-liquid turbulence model. This turbulent diffusion model was then compared with the results of the CFD investigation making use of the same boundary conditions. The comparison established good agreement between these two models. The influence of velocity on the particle size distribution was dominant over the influence of the superficial liquid velocity, which was also explained by using the new parameter, velocity ratio. This velocity ratio was defined as the ratio between the free flight and gravitational velocity. Due to some inevitable assumptions used in the analytical model, the results showed typically less deposition as compared with the CFD investigation.
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Decentralized control of distributed generation in future distribution networksZhang, Zedong January 2017 (has links)
Environmental targets set by governments around the world are leading to high penetrations of small to medium-scale renewable distributed generation (DG). High penetration of DG in distribution networks, however, can result in voltage and thermal issues among other technical problems. The traditional 'Fit & Forget' approach that refers to the passive use of assets with limited or no control, in the context of distribution network planning, is used to meet maximum demand or generation requirements. However, to ensure that more renewable generation is cost-effectively connected to distribution networks, it is imperative to adopt a more active control of network elements and participants. The active control of future distribution networks requires understanding the corresponding dependencies between voltage magnitudes and DG active/reactive power outputs to mitigate voltage issues. One classical method to calculate these dependencies is to use sensitivity approaches such as those based on the Jacobian matrix. However, during operation, updating the Jacobian matrix requires the network to be fully observable making it unfeasible for decentralized control approaches. Therefore, it is critical to develop a sensitivity approach only requiring local real-time information. This thesis proposes a novel approach to produce voltage sensitivity coefficients using the surface fitting technique based solely on knowledge of network characteristics and, therefore, no remote monitoring is required. To assess the performance of the proposed voltage sensitivity approach, a decentralized (local) voltage control algorithm that simultaneously caters for both the active and reactive power outputs of a single DG plant is adopted. Comparisons with classical sensitivity approaches are carried out using the 16-bus UK GDS test network, 1-min resolution demand and wind generation data. Persistence forecasting (i.e., assuming no changes in demand and wind in a short time period) is considered in this case. The lower Mean Squared Error (MSE) shows that the coefficients of the proposed sensitivity approach are close to those of the Jacobian matrix and better than the perturb-and-observe approach. In the context of voltage management, results highlight that the proposed sensitivity approach is more effective than the Jacobian matrix inverse and perturb-and-observe, resulting in better voltage compliance and energy harvesting (better capacity factor). It should be highlighted that this performance is achieved without the need of full network observability. Furthermore, to cater for the more realistic and complex case of multiple DG plants, this thesis proposes a time-delay based decentralized control algorithm. A comparison with an ideal AC Optimal Power Flow (OPF) is carried out using the same 16-bus UK GDS network but with seven DG plants. The results demonstrate that the proposed sensitivity approach and time delays are very effective when compared to the AC OPF. This, in turn, proves that the combined use of the proposed voltage sensitivity approach and the decentralized controller is an implementable, cost-effective solution to manage DG plants in distribution networks without the need of further communication infrastructure. Finally, a decentralized DG control logic with the capability of using wind forecasting techniques is proposed to tackle the unpredictable nature of wind power. In this work, a time-series based forecasting technique is incorporated to the proposed decentralized controller. The results confirm that the use of more advanced forecasting technique can further improve the management of renewable DG plants.
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Estudo de caso brasileiro sobre redes de distribuição / Brazilian case study on supply chainQuagliato, Giuliano Batagin 12 August 2018 (has links)
Orientador: Douglas Tacla / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-12T11:18:25Z (GMT). No. of bitstreams: 1
Quagliato_GiulianoBatagin_M.pdf: 1392096 bytes, checksum: 2348fe37c161006a95ff3803b0ad4412 (MD5)
Previous issue date: 2009 / Resumo: Atualmente, há uma grande quantidade de pesquisas realizadas para determinar o perfil de redes de distribuição em função de conceitos existentes na literatura. Há vários estudos disponíveis que apresentam modelos com base em variáveis que ao serem combinadas entre si proporcionam determinações teóricas de redes de distribuição, tais quais, volumes, distâncias, entre outros. Em contra partida, existem no mercado empresas do setor logístico que operam através de redes de distribuição construídas com embasamento prático para atender uma demanda de clientes de qualquer parte do país ou do mundo. Sendo assim, esta dissertação de mestrado visa realizar um estudo sobre redes de distribuição comparativamente aos modelos propostos na literatura disponível e confrontar com a realidade de redes de distribuição do Brasil através de um estudo de caso. Para isso, a proposta é utilizar dados provenientes de um operador logístico para que, quando aplicados, seja possível comparar métodos propostos na literatura de redes de distribuição com resultados práticos. Feitas as comparações relevantes, cria-se um procedimento e calculam-se os custos de transportes e de armazenagem através de uma ferramenta de análise e identificam-se potenciais ganhos monetários. Por fim, a conclusão se dá com exposição dos resultados obtidos através da aplicação dos procedimentos criados e comparando as fontes sobre redes de distribuição validadas através da aplicação de dados reais. / Abstract: At the present, there is a big quantity of researches to determine the profile of the supply chain in function of existent concepts in the literature. There are several available studies that present models based on variables that while being combined between each other provide theoretical determinations of supply chain, just like, volumes, distances, between others. On the other hand, there are in the market companies of the logistics sector which operate through supply chain built with practical foundation to attend a clients' demand of any part of the country or of the world. Being so, this dissertation of master's degree aims to carry out a study on supply chain comparatively to the models proposed in the available literature and to confront with the reality of supply chain of Brazil through a case study. For that, the proposal is to use data originating from a Third Party Logistics Provider to, when applied, be possible to compare methods proposed in the literature on supply chain with practical results. When the relevant comparisons were done, a proceeding is created and the transportation and storage costs are calculated through a tool of analysis and the potential monetary profits are identified. Finally, the conclusion will be with the exhibition of the results obtained through the application of the procedures previously built and comparing with the sources on supply chain and taking the application of real case as a validation. / Mestrado / Transportes / Mestre em Engenharia Civil
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The Dual Use of Power Distribution Networks for Data Communications in High Speed Integrated CircuitsChung, Woo Cheol 17 February 2006 (has links)
This thesis investigates a new data communication method in high speed integrated circuits using power distribution networks (PDNs). The conventional purpose of PDNs in integrated circuits (ICs) is to deliver power to internal nodes of an IC while meeting a level of power integrity. As the power consumption increases for very large scale integration (VLSI) systems, the number of power/ground pins increases as well. In this thesis, we propose to use PDNs for dual purposes, delivery of power and one-/two-way data communications, which is highly beneficial for pin-limited high performance ICs. To this end, we investigate signaling methods for a microscopic communication channel. Impulse-based ultra wideband (UWB) signaling is selected due to its robustness to noise and wideband characteristics. Next, we study a planar structure IC package based on the cavity resonator model (CRM) as a communication channel. Impedance characteristics of a planar structure IC package and other relevant components of an IC are important, and they are investigated for data transmission over power distribution networks. Another important aspect of the study is data transmission and reception, which we investigate through simulations. Finally, we study one possible application for one way communications, massive parallel scan design, which greatly shortens the testing time at moderate overhead. The performance is measured with eye diagrams and bit error rates (BERs) under the presence of voltage drop, simultaneous switching noise, and thermal noise. / Ph. D.
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Artificial Neural Network Model for a Low Cost Failure Sensor: Performance Assessment in Pipeline DistributionKhan, Asar, Widdop, Peter D., Day, Andrew J., Wood, Alastair S., Mounce, Steve R., Machell, James January 2006 (has links)
Yes / This paper describes an automated event detection and
location system for water distribution pipelines which is based upon
low-cost sensor technology and signature analysis by an Artificial
Neural Network (ANN). The development of a low cost failure
sensor which measures the opacity or cloudiness of the local water
flow has been designed, developed and validated, and an ANN based
system is then described which uses time series data produced by
sensors to construct an empirical model for time series prediction and
classification of events. These two components have been installed,
tested and verified in an experimental site in a UK water distribution
system. Verification of the system has been achieved from a series of
simulated burst trials which have provided real data sets. It is
concluded that the system has potential in water distribution network
management.
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Antiresonance and Noise Suppression Techniques for Digital Power Distribution NetworksDavis, Anto K January 2015 (has links) (PDF)
Power distribution network (PDN) design was a non-existent entity during the early days of microprocessors due to the low frequency of operation. Once the switching frequencies of the microprocessors started moving towards and beyond MHz regions, the parasitic inductance of the PCB tracks and planes started playing an important role in determining the maximum voltage on a PDN. Voltage regulator module (VRM) sup-plies only the DC power for microprocessors. When the MOSFETs inside a processor switches, it consumes currents during transition time. If this current is not provided, the voltage on the supply rails can go below the specifications of the processor. For lower MHz processors few ceramic-capacitors known as ‘decoupling capacitors’ were connected between power and ground to provide this transient current demand. When the processor frequency increased beyond MHz, the number of capacitors also increased from few numbers to hundreds of them. Nowadays, the PDN is said to be comprising all components from VRM till the die location. It includes VRM, bulk capacitors, PCB power planes, capacitor mounting pads and vias, mount for the electronic package, package capacitors, die mount and internal die capacitance. So, the PDN has evolved into a very complex system over the years.
A PDN should provide three distinct roles; 1) provide transient current required by the processor 2) act as a stable reference voltage for processor 3) filter out the noise currents injected by the processor. The first two are required for the correct operation of the processor. Third one is a requirement from analog or other sensitive circuits connected to the same PDN. If the noise exits the printed circuit board (PCB), it can result in conducted and radiated EMI, which can in turn result in failure of a product in EMC testing.
Every PDN design starts with the calculation of a target impedance which is given as the ratio of maximum allowed ripple voltage to the maximum transient current required by the processor. The transient current is usually taken as half the average input current. The definition of target impedance assumes that the PDN is flat over the entire frequency of operation, which is true only for a resistive network. This is seldom true for a practical PDN, since it contains inductances and capacitances. Because of this, a practical PDN has an uneven impedance versus frequency envelope. Whenever two capacitors with different self resonant frequencies are connected in parallel, their equivalent impedance produces a pole between the self resonant frequencies known as antiresonance peaks. Because of this, a PDN will have phase angles associated with them. Also, these antiresonance peaks are energy reservoirs which will be excited during the normal operation of a processor by the varying currents.
The transient current of a microprocessor is modeled as a gamma function, but for practical cases it can be approximated as triangular waveforms during the transition time which is normally 10% of the time period. Depending upon the micro-operations running inside the processor, the peak value of this waveform varies. This is filtered by the on-chip capacitors, package inductance and package capacitors. Due to power gating, clock gating, IO operations, matrix multiplications and magnetic memory readings the waveforms at the board will be like pulse type, and their widths are determined by these operations. In literatures, these two types of waveforms are used for PDN analysis, depending upon at which point the study is conducted.
Chapter 1 introduces the need for PDN design and the main roles of a PDN. The issue of antiresonance is introduced from a PDN perspective. Different types of capacitors used on a PDN are discussed with their strengths and limitations. The general nature of the switching noise injected by a microprocessor is also discussed. This chapter discusses the thesis contributions, and the existing work related to the field.
Chapter 2 introduces a new method to calculate the target impedance (Zt ) by including the phase angles of a PDN which is based on a maximum voltage calculation. This new Zt equals to conventional Zt for symmetrical triangular switching current waveforms. The value of new Zt is less than the conventional Zt for trapezoidal excitation patterns. By adding the resonance effects into this, a maximum voltage value is obtained in this chapter. The new method includes the maximum voltage produced on a PDN when multiple antiresonance peaks are present. Example simulations are provided for triangular and pulse type excitations. A measured input current wave-form for PIC16F677 microcontroller driving eight IO ports is provided to prove the assumption of pulse type waveforms.
For triangular excitation waveform, the maximum voltage predicted based on the expression was ¡0.6153 V, and the simulated maximum voltage was found to be at ¡0.5412 V which is less than the predicted value. But the predicted value based on Zt method was 1.9845 V. This shows that the conventional as well as the new target impedance method leads to over estimating the maximum voltage in certain cases. This is because most of the harmonics are falling on the minimum impedance values on a PDN. If the PDN envelope is changed by temperature and component tolerances, the maximum voltage can vary. So the best option is to design with the target impedance method. When pulse current excitation was studied for a particular PDN, the maximum voltage produced was -139.39 mV. The target impedance method produced a value of -100.24 mV. The maximum voltage predicted by the equation was -237 mV. So this shows that some times the conventional target impedance method leads to under estimating the PDN voltage. From the studies, it is shown that the time domain analysis is as important as frequency domain analysis. Another important observation is that the antiresonance peaks on a PDN should be damped both in number and peak value.
Chapter 3 studies the antiresonance peak suppression methods for general cases. As discussed earlier, the antiresonance peaks are produced when two capacitors with different self resonant frequencies are connected in parallel. This chapter studies the effect of magnetic coupling between the mounting loops of two capacitors in parallel. The mounting loop area contribute to the parasitic inductance of a capacitor, and it is the major contributing factor to it. Other contributing factors are equivalent series inductance (ESL) and plane spreading inductance. The ESL depends on the size and on how the internal plates of the capacitors are formed. The spreading inductance is the inductance contributed by the parts of the planes connecting the capacitor connector vias to the die connections or to other capacitor vias. If the power and ground planes are closer, the spreading inductance is lower. On one/two layer boards dedicated power/ground planes are absent. So the spreading inductance is replaced by PCB track inductances. The inductance contributed by the mounted area of the capacitor is known as mounting inductance. On one/two layer boards dedicated power/ground planes are absent. So the spreading inductance is replaced by PCB track inductances. The dependencies of various circuit parameters on antiresonance peak are studied using circuit theory. A general condition for damping the antiresonance is formulated. The antiresonance peak reduces with Q factor. The conventional critical condition for antiresonance peak damping needs modification when magnetic coupling is present between the mounting loops of two parallel unequal value capacitors. By varying the connection geometry it is possible to obtain negative and positive coupling coefficients. The connection geometries to obtain these two are shown. An example is shown for positive and negative coupling coefficient cases with simulation and experimental results. For the example discussed, RC Æ 32 - for k Æ Å0.6 and RC Æ 64 - for k Æ ¡0.6, where RC is the critical damping value and k is the magnetic coupling coefficient between the two mounting loops. The reason for this is that, the antiresonance peak impedance value is higher for negative coupling coefficient case than that for positive coupling coefficient case.
Above the self resonant frequencies of both the capacitors, the equivalent impedance of the parallel capacitors become inductive. This case is studied with two equal value capacitors in parallel. It is shown that the equivalent inductance is lower for negative coupling coefficient case as compared to positive coupling coefficient case. An example is provided with simulation and experimental results. In the experimental results, parasitic inductance is observed to be 2.6 times lower for negative coupling coefficient case than that for positive coupling coefficient case. When equal value capacitors are connected in parallel, it is advantageous to use a negative coupling geometry due to this.
Chapter 4 introduces a new method to damp the antiresonance peak using a magnet-ically coupled resistive loop. Reducing the Q factor is an option to suppress the peak. In this new method, the Q factor reduction is achieved by introducing losses by mag-netically coupling a resistive loop. The proposed circuit is analyzed with circuit-theory, and governing equations are obtained. The optimum value of resistance for achieving maximum damping is obtained through analysis. Simulation and experimental results are shown to validate the theory. From the experimental results approximately 247 times reduction in antiresonance peak is observed with the proposed method. Effectiveness of the new method is limited by the magnetic coupling coefficient between the two mounting loops of capacitors. The method can be further improved if the coupling coefficient can be increased at the antiresonance frequency.
Chapter 5 focuses on the third objective of a PDN, that is to reduce the noise injected by the microprocessor. A new method is proposed to reduce the conducted noise from a microprocessor with switched super capacitors. The conventional switched capacitor filters are based on the concept that the flying capacitor switching at high frequency looks like a resistor at low frequency. So for using at audio frequencies the flying capacitors were switching at MHz frequencies. In this chapter the opposite of this scenario is studied; the flying capacitors are the energy storage elements of a switched capacitor converter and they switch at lower frequencies as compared to the noise frequencies.
Two basic circuits (1:1 voltage conversion ratio) providing noise isolation were discussed. They have distinct steady state input current waveforms and are explained with PSPICE simulations. The inrush current through switches are capable of destroying them in a practical implementation. A practical solution was proposed using PMOS-PNP pair. The self introduced switching noise of the converter is lower when switching frequency is low and turn ON-OFF time is higher. If power metal oxide semiconductor field effect transistor (MOSFET)s are used, the turn ON and turn OFF are slow. The switching frequency can be lowered based on the voltage drop power loss. The governing equations were formulated and simulated. It is found that the switching frequency can be lowered by increasing the capacitance value without affecting the voltage drop and power loss. From the equations, it is found that the design parameters have a cyclic dependency. Noise can short through the parasitic capacitance of the switches. Two circuits were proposed to improve the noise isolation: 1) T switch 2) ¦ switch. Of these, the ¦ switch has the higher measured transfer impedance. Experimental results showed a noise reduction of (40-20) dB for the conducted frequency range of 150 kHz - 30 MHz with the proposed 1:1 switched capacitor converter. One possible improvement of this method is to combine the noise isolation with an existing switched capacitor converter (SCC) topology. The discussed example had a switching frequency of 700 Hz, and it is shown that this can isolate the switching noise in kHz and MHz regions. In a PDN there are antiresonance peaks in kHz regions. If the proposed circuit is kept close to a microprocessor, it can reduce the excitation currents of these low frequency antiresonance peaks.
Chapter 6 concludes the thesis by stating the major contributions and applications of the concepts introduced in the thesis. This chapter also discusses the future scope of these concepts.
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Reducing the cumulative file download time and variance in a P2P overlay via proximity based peer selectionCarasquilla, Uriel J. 01 January 2013 (has links)
The time it takes to download a file in a peer-to-peer (P2P) overlay network is dependent on several factors. These factors include the quality of the network between peers (e.g. packet loss, latency, and link failures), distance, peer selection technique, and packet loss due to Internet Service Providers (ISPs) engaging in traffic shaping. Recent research shows that P2P download time is adversely impacted by the presence of distant peers, particularly when traffic goes across an ISP that could be engaging in P2P traffic throttling activities. It has also been observed that additional delays are introduced when distant candidate nodes for exchanging data are included during the formation of a P2P network overlay. Researchers have shifted their attention to the mechanism for peer selection. They started questioning the random technique because it ignores the location of nodes in the topology of the underlying physical network. Therefore, selecting nodes for interaction in a distributed system based on their position in the network continues to be an active area of research. The goal of this work was to reduce the cumulative file download time and variance for the majority of participating peers in a P2P network by using a peer selection mechanism that favors nearby nodes. In this proposed proximity strategy, the Internet address space is separated by IP blocks that belong to different Autonomous Systems (AS). IP blocks are further broken up into subsets named zones. Each zone is given a landmark (a.k.a. beacon), for example routers or DNS servers, with a known geographical location. At the time peers joined the network, peers were grouped into zones based on their geographical distance to the selected beacons. Peers that end up in the same zone were put at the top of the list of available nodes for interactions during the formation of the overlay. Experiments were conducted to compare the proposed proximity based peer selection strategy to the random peer selection strategy. The results indicate that the proximity technique outperforms the random approach for peer selection in a network with low packet loss and latency and also in a more realistic network subject to packet loss, traffic shaping and long distances. However, this improved performance came at the cost of additional memory (230 megabytes) and to a lesser extent some additional CPU cycles to run the additional subroutines needed to group peers into zones. The framework and algorithms developed for this work made it possible to implement a fully functioning prototype that implements the proximity strategy. This prototype enabled high fidelity testing with a real client implementation in real networks including the Internet. This made it possible to test without having to rely exclusively on event-driven simulations to prove the hypothesis.
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Adaptive control for active distribution networksSansawatt, Thipnatee Punim January 2012 (has links)
Rise of the global environmental awareness and climate change impacts caused by greenhouse gases emissions brings about a revolution in the power and energy industries to reduce fossil fuels and promote low-carbon and renewable distributed generation (DG). The new dimensions, mainly encouraged by the governments’ legislative targets and incentives, have allowed the development of DG worldwide. In the U.K., renewable DG especially wind is being connected on distribution networks and ranges widely in scales. Despite the growing number of potential DG sites, the surplus generation present on the passive networks can lead to some technical problems. In particular, rural networks where wind farms exist are prone to voltage rise and line thermal constraints. In order to accommodate new DG and ensure security of supply and network reliability, active management to mitigate these issues are required. In addition, the duties to provide cost-effective DG connections at avoided expensive investment incurred from conventional solutions, e.g., reinforcement and maintain robust network are a major challenge for Distribution Network Operators (DNOs). This thesis endeavours to develop an adaptive control scheme that provides local and real-time management against voltage variations and line capacity overload at the point of wind connections on rural distribution networks. Taking into account maximising power exports and providing an economically-viable control scheme, the wind turbine’s capability, comprising reactive power control and active power curtailment, is used. Whilst the thesis concentrates on the decentralised control applying several different algorithms, in addition, semi-coordinated and centralised approaches that adopt on-load tap changing transformers’ regulation and Optimal Power Flow tool are developed. Comparisons of these approaches based upon measures, i.e., economics, DG penetration and performance are determined. As an outcome, the developed scheme can enable growing integration of renewable DG on distribution networks and can be seen as an interim solution for the DNOs towards Smart Distribution Networks.
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[en] APPLICATION OF MATHEMATICAL MODELING TO OPTIMIZE ASPHALT DISTRIBUTION IN BRAZIL: A CASE STUDY / [pt] APLICAÇÃO DE MODELAGEM MATEMÁTICA NA OTIMIZAÇÃO DA DISTRIBUIÇÃO DE ASFALTOS NO BRASIL: UM ESTUDO DE CASOLEONARDO NOGUEIRA FINAMORE 07 April 2015 (has links)
[pt] A demanda por asfaltos vem crescendo fortemente no Brasil por conta do
ciclo vigoroso de expansão e recuperação de obras viárias de novos
empreendimentos em rodovias, portos e aeroportos, que compõem o PAC –
Programa de Aceleração do Crescimento. Neste cenário, a otimização da
distribuição de asfaltos faz-se necessária para garantir o abastecimento do produto
no país. Diante deste contexto, foi desenvolvido um modelo de programação
linear que permite avaliar as alternativas de atendimento ao mercado de asfaltos,
considerando minimizar os custos operacionais envolvidos na entrega aos polos
de venda, a partir das refinarias produtoras. O modelo proposto foi aplicado em
um estudo de caso que considerou a necessidade da criação de um novo polo de
venda, em complemento aos polos atualmente existentes. O resultado obtido
permite fundamentar a tomada de decisão na escolha da alternativa que garanta o
atendimento ao mercado do país com o menor custo. / [en] The demand for asphalt has been growing strongly in Brazil because of the
vigorous cycle of expansion and recovery of roadworks and new projects in roads,
ports and airports which comprises the PAC - National Growth Acceleration
Program. Given this context, the optimization of asphalt distribution is needed to
ensure the supply of the product in the country. In this context, we propose a
linear programming model that allows to evaluate alternative services for the
asphalt market, considering the minimization of operational costs involved in
delivering asphalt from the refineries to the selling locations. The proposed model
was evaluated through a case study that addressed the need of creating a new
center for delivery, in addition to the currently existing poles. Results obtained
were able to support the decision making in choosing the alternative that ensures
compliance with the country s market at the lowest cost.
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Operação otimizada do sistema adutor metropolitano utilizando algoritmos genéticos: estudo de caso - SAM Leste da Região Metropolitana de São Paulo (R.M.S.P.). / Optimized operation of metropolitan mains system using genetic algorithms: case study - East Metropolitan Mains System of Metropolitan Region of São Paulo (M.R.S.P.).Ribeiro, Gracione Picanço 27 October 2005 (has links)
O presente trabalho apresenta uma avaliação de otimização de um sistema complexo de adução de água tratada, em tempo real, com Algoritmos Genéticos (AGs), associado a um sistema SCADA e a um modelo de simulação hidráulica de rede (Epanet 2.0). Foram utilizados registros históricos de consumos de água, considerados como previsão perfeita. O estudo de caso foi feito em uma parte do Sistema Adutor Metropolitano (SAM) de São Paulo para minimizar uma função multiobjetivo (custos de energia e restrições operacionais). Foram analisados seis cenários com diversas combinações de pesos, tamanhos da população, número de gerações e probabilidades de cruzamento e mutação. As estratégias de operação obtidas permitiram reduções de até 22% na potência consumida e uma redução expressiva do custo de energia pela redução dos bombeamentos nos horários de tarifas mais elevadas. / This work presentss an evaluation of optimization of real time operation of a complex water supply system. Genetic Algorithm associated with a SCADA system and a network hydraulic simulation model was applied. Observed historic consumptions were used as a perfect water demand forecast model. Case study is the optimization of a multiobjective function (energy cost and operational restrictions) subsystem of Water Mains System of São Paulo Metropolitan Region. Six representative combinations of population size, number of generations , crossover and mutation probabilities were analyzed, Operational schedule of pumping and valve controls led to reductions in power consumptions up to 22% and expressive lower operational costs due to reductions of pumping in eenrgy peak times.
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