Orientador: Antonio Padilha Feltrin / Banca: Antonio Marcos Cossi / Banca: Carlos Roberto Minussi / Banca: Walmir de Freitas Filho / Banca: José Antonio Domínguez Navarro / Resumo: O objetivo principal deste projeto é o desenvolvimento de metodologias que indiquem os custos reais de determinados serviços ancilares de geradores distribuídos, e como podem contribuir, com estes serviços, para melhoria da qualidade do fornecimento de energia na distribuição, subtransmissão e até transmissão. Estas metodologias deverão fornecer os custos destes serviços, bem como os benefícios para o sistema elétrico, além de identificar quem e quanto oferece de cada serviço para a operação segura e dentro dos procedimentos preestabelecidos. Para o desenvolvimento dos algoritmos de solução são considerados dois tipos de geração distribuida: geradores distribuídos com variabilidade da fonte primária de energia mínima ou desprezível (microturbinas a gás, pequenas centrais hidrelétricas, geradores em usinas de açúcar e álcool, etc.), e geradores distribuídos que tem forte dependência das variações da fonte primária de energia (principalmente turbinas eólicas e sistemas fotovoltaicos). Este último grupo de geradores precisa de considerações mais elaboradas que incluam as incertezas na geração de energia. Este assunto é tratado através de Simulações de Monte Carlo, Cadeias de Markov e Lógica Fuzzy. Através das Simulações de Monte Carlo são realizados fluxos de potência probabilísticos em múltiplos cenarios, enquanto que com as Cadeias de Markov e a Lógica Fuzzy são descritas as séries de tempo relacionadas com a geração de potência ativa dos geradores distribuídos. Também sãoconsiderados vários objetivos a serem otimizados através de técnicas multiobjetivo, observando principalmente as perdas de potência nas linhas do sistema, os custos de geração dos geradores distribuídos e a estabilidade de tensão ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The main objective of this project is to develop methodologies to indicate the real costs of certain ancillary services when they are delivered by distributed generators, and how they can contribute, with these services, to improve the quality of power supply in distribution, subtransmission and even transmission systems. These methodologies should provide the costs of these services and benefits to the electrical system as a whole, and they should also identify who and how much of each service provides for the safe operation and within the pre-established procedures. Two types of distributed generation are considered for the development of solution algorithms: distributed generators with minimal or negligible variability of the primary energy source (gas micro-turbines, small hydroelectric plants, generators in sugar and alcohol plants, etc.), and distributed generators that have strong dependence on variations of the primary energy source (mainly wind turbines and photovoltaic systems). This latter group of generators need more elaborate considerations to include the uncertainties in power generation. This matter is addressed through Monte Carlo Simulations, Markov Chains and Fuzzy Logic. Through Monte Carlo Simulations probabilistic power flows in multiple scenarios are performed, while with Markov Chains and Fuzzy Logic the time series related to the active power generation of distributed generators are described. Several objectives are also considered to be optimized by multi-objective techniques, noting particularly the power losses in the lines of the system, generation costs of distributed generators and voltage stability of the system. The ancillary services considered in this work are reactive power support, reserves for frequency control and secondary frequency control. Reactive power support... (Complete abstract click electronic access below) / Doutor

In this research, the problem of real-time congestion management in a modern distribution system with massive active elements such as electric vehicles (EVs), distributed energy resources (DERs), and demand response (DR) is investigated. A novel hierarchical operation and management framework is proposed that can take advantage of the demand side contribution to manage the real-time congestion. There are five main steps in this framework as 1) the aggregators send their demand to the microgrid operators (MGOs), 2) the MGOs send their demand to the distribution system operator (DSO), 3) the DSO detects the congestions and calls the engaged MGOs to reduce their demand, 4) the MGOs update the electricity price to motivate the aggregators to reduce the overall demand, and 5) the DSO dispatches the system according to the finalized demand. The proposed framework is validated on two modified IEEE unbalanced test systems. The results illustrate two congestion cases at t=8:45 am and t=9:30 am in the modified IEEE 13-bus test system, which needs 363kW and 286 kW load reductions, respectively, to be fully addressed. MG#1 and MG#2 are engaged to maintain the 363 kW reduction at t=8:45, and MG#3 and MG#4 are called to reduce their demands by 386 kW at t=9:30 am. The overall interactions can relieve the congested branches. The DSO’s calculations show three congestions at t=1 pm, t=3 pm, and t=9 pm on the IEEE 123-bus test system. These congestion cases can be alleviated by reducing 809 kW, 1177 kW, and 497 kW from the corresponding MGs at t=1 pm, t=3 pm, and t=9 pm, respectively. The second part of the simulation results demonstrates that the proposed real-time data estimator (RDE) can reduce the DSO’s miss-detected congestion cases due to the uncertain data. There are two miss-detected congestions in the IEEE 13-bus test system at t=1:15 pm and t=1:30 pm that can be filtered for t=1:15 pm and minored for t=1:30 pm using the RDE. The proposed RDE can also reduce the miss-detected congestions from 18 cases to four cases in the IEEE 123-bus test system. As a result, the RDE can minimize the extra costs due to the uncertain data. The overall results validate that the proposed framework can adaptively manage real-time congestions in distribution systems.

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In Europe, the prices of natural gas and electricity reached an all-time high during 2022. An approach tomitigate these high prices is to expand the district heating systems in urban areas, this will reduceelectric load as well as to increase the power production in combined heat and power plants. Districtheating has been the dominant heat supply technology in urban areas in Sweden since the 1980s.However, as the number of low energy buildings are increasing, district heating distribution losses mustbe reduced to ensure cost-efficient consumer demand supply. This has led to the idea of the 4th-generation district heating which is characterized by low distribution temperatures.The aim of this study is to simulate low temperature distribution systems in a planned future city districtusing a Python based simulation tool and compare the results with a conventional system. Threedifferent types of low temperature distribution systems are investigated: 1) domestic hot water andspace heating separated, 2) apartment heat exchangers, 3) a cascading low temperature system.Focus is on simulating the distribution losses, distribution temperature and mass flow in the area, butthe scope of the analysis also includes an investigation of the effect of lower return temperatures to thecombine heat and power plant. The result indicate which type of system is most beneficial to implementin this specific area.With regards of distribution losses and temperature drop performs the low temperature distributionsystem with apartment heat exchangers better than the cascading system and the system withdomestic hot water and space heating separated. The mass flow is highly dependent of the temperaturedemand in the heating systems in the buildings and is higher for all low temperature distributionsystems compared to a conventional system.

tudies in teaching and non-teaching hospitals have shown that one- quarter to one-third of all patients receive an antimicrobial (AMC) drug during their hospital stay." 1-30 Many of these patients (ranging from 30 to 60%), particularly those on the surgical services, have no definite evidence of infection. Inquiry regarding the use of AMC drugs can be traced back more than two decades. In 1961, the Commission on Professional and Hospital Activities in its Professional Activity Study (CPHA-PAS) surveyed 24 hospitals." They found that approximately 27% of all patients were given an AMC drug; however, it was estimated by PAS that only about 12% of these patients should have received AMC therapy under the most conservative medical practice.

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The purpose of this study was to identify the effect that water quality, pipe material, pipe size, flow conditions and the use of corrosion inhibitors would have on the rate of free chlorine and chloramine decay in distribution systems. Empirical models were developed to predict the disinfectant residual concentration with time based on the parameters that affected it. Different water treatment processes were used to treat groundwater and surface water to obtain 7 types of finished waters with a wide range of water quality characteristics. The groundwater was treated either by conventional treatment by aeration (G1) or softening (G2) or high pressure reverse osmosis (RO) and the surface water was treated either by enhanced coagulation, ozonation and GAC filtration (CSF-O3-GAC or S1) or an integrated membrane system (CSF-NF or S2). The remaining two water types were obtained by treating a blend of G1, S1 and RO by softening (S2) and nanofiltration (G4). A pilot distribution systems (PDS) consisting of eighteen (18) lines was built using old pipes obtained from existing distribution system. The pipe materials used were polyvinyl chloride (PVC), lined cast iron (LCI), unlined cast iron (UCI) and galvanized steel (G). During the first stage of the study, the 7 types of water were blended and fed to the PDS to study the effect of feed water quality changes on PDS effluent water quality, and specifically disinfectant residual. Both free chlorine and chloramines were used as disinfectant and the PDSs were operated at hydraulic retention times (HRT) of 2 and 5 days. The PDSs were periodically tested for free and combined chlorine, organic content, temperature, pH, turbidity and color. The data obtained were used to develop separate models for free chlorine and chloramines. The best fit model was a first-order kinetic model with respect to initial disinfectant concentration that is dependent on the pipe material, pipe diameter and the organic content and temperature of the water. Turbidity, color and pH were found to be not significant for the range of values observed. The models contain two decay constants, the first constant (KB) accounts for the decay due to reaction in the bulk liquid and is affected by the organics and temperature while the second constant, KW, represents the reactions at the pipe wall and is affected by the temperature of the water and the pipe material and diameter. The rate of free chlorine and chloramine decay was found to be highly affected by the pipe material, the decay was faster in unlined metallic pipes (UCI and G) and slower in the synthetic (PVC) and lined pipes (LCI). The models showed that the rate of disinfectant residual loss increases with the increase of temperature or the organics in the water irrespective of pipe material. During the second part of the study, corrosion control inhibitors were added to a blend of S1, G1 and RO that fed all the hybrid PDSs. The inhibitors used were: orthophosphate, blended ortho-polyphosphate, zinc orthophosphate and sodium silicate. Three PDSs were used for each inhibitor type, for a total of 12 PDSs, to study the effect of low, medium and high dose on water quality. Two PDSs were used as control, fed with the blend without any inhibitor addition. The control PDSs were used to observe the effect of pH control on water quality and compare to the inhibitor use. One of the control PDSs (called PDS 13) had the pH adjusted to be equal to the saturation pH in relation to calcium carbonate precipitation (pHs) while the pH of the other control PDS (PDS 14) was adjusted to be 0.3 pH units above the pHs. The disinfectant used for this part of the study was chloramine and the flow rates were set to obtain a HRT of 2 days. The chloramine demand was the same for PDS 14 and all the PDSs receiving inhibitors. PDS 13 had a chloramine demand greater than any other PDS. The lowest chloramine demand was observed in PDS 12, which received silicate inhibitor at a dose of 12 mg/L, and presented the highest pH. The elevation of pH of the water seems to reduce the rate of decay of chloramines while the use of corrosion inhibitors did not have any effect. on the rate of chloramine decay. The PDS were monitored for chloramine residual, temperature, pH, phosphate, reactive silica, and organic content. Empirical models were developed for the dissipation of chloramine in the pilot distribution systems as a function of time, pipe material, pipe diameter and water quality. Terms accounting for the effect of pH and the type and dose of corrosion inhibitor were included in the model. The use of phosphate-based or silica-based corrosion inhibitors was found to have no effect on the rate of chloramine dissipation in any of the pipe materials. Only the increase of pH was found to decrease the rate of chloramine decay. The model to best describe the decay of chloramine in the pilot distribution systems was a first-order kinetic model containing separate rate constants for the bulk reactions, pH effect and the pipe wall reactions. The rate of chloramine decay was dependent on the material and diameter of the pipe, and the temperature, pH and organic content of the water. The rate of chloramine decay was low for PVC and LCI, and more elevated in UCI and G pipes. Small diameter pipes and higher temperatures increase the rate of chlorine decay irrespective of pipe material. Additional experiments were conducted to evaluate the effect of flow velocity on chloramine decay in a pilot distribution system (PDS) for different pipe materials and water qualities. The experiments were done using the single material lines and the flow velocity of the water was varied to obtain Reynolds' numbers from 50 to 8000. A subset of experiments included the addition of blended orthophosphate corrosion inhibitor (BOP) at a dose of 1.0 mg/L as P to evaluate the effect of the inhibitor on chloramine decay. The effect of Reynolds' number on the overall chloramine decay rate (K) and the wall decay rate constant (W) was assessed for PVC, LCI, UCI, and G pipes. PVC and LCI showed no change on the rate of chloramine decay at any flow velocity. UCI and G pipes showed a rapid increase on the wall decay rate under laminar conditions (Re ≤ 500) followed by a more gradual increase under fully turbulent flow conditions (Re ≥ 2000). The use of the BOP inhibitor did not have an effect on the rate of chloramine decay for any of the pipe materials studied. Linear correlations were developed to adjust the rate of chloramine decay at the pipe wall for UCI and G depending on the Reynolds' number.

The standard design approach of water distribution systems requires that pressure at any point in the system is maintained within a range whereby the maximum pressure is not exceeded so that the likelihood of a pipe burst is reduced and the minimum pressure is always maintained or exceeded to ensure adequate flows for satisfying expected demands. High pressure systems tend to cause more frequent pipe breaks and an increase in energy use and leakage. Low pressure systems cause consumer complaints, make the system more susceptible to negative pressures, and possibly to the ingress of contaminants during transient events. The overall goal of establishing pressure standards is to balance these opposing tendencies to achieve a safe, reliable, and economic operation of the system. Yet, there are no universally acceptable or established rules or guidelines for establishing a pressure standard for water distribution system design, and few studies have considered whether the traditional standards are still applicable in modern systems. This study has made a critical appraisal on what pressure standards mean, where they are violated, and where they need revision to achieve a comprehensive picture about what the pressure standards really mean. The research also highlights the inter-related issues associated with pressure criteria. Assessment of the relationships governing water pressure, leakage, energy use and economics is realized via the analytical investigation of single pipes and the simulation of representative networks using the steady state analysis software EPANET 2. The role of minimum pressure standards, storage, pumping strategy, and resource prices on the energy and water loss of systems is analysed and assessed. In anticipation that pressure contributes to pipe break rates, a probabilistic approach considering uncertain water demand and pipe’s roughness modeled with a Monte Carlo simulation (MCS) algorithm is presented. This study also explores how the minimum pressure standards affect transient pressures and reviews how destructive transient pressures may be controlled to limit reduced pressure surges within acceptable limits even when the minimum steady state pressure is relatively low. In order to place the research in practical context, this study develops a surge limit control algorithm for the design of a portable device for limiting the down-surge pressures by creating a pressure control boundary in a pipe system during hydrant operations. This boundary is established using the portable control device to safely operate a hydrant in a water distribution system. This study also highlights the notion that high level of pressure standards may lead to a troublesome squandering of water and energy and may disrupt the performance of water distribution systems. Given the too often degraded nature of water supply infrastructures, the on-going challenges of urban growth, and the increased stress on natural resources, the significant benefits of better controlling water pressure are not only welcome but urgently needed. / Thesis / Doctor of Philosophy (PhD)

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