Dissertations / Theses on the topic 'Forming and distribution of losses'
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Ozel, Kerem. "Losses In Electric Distribution System." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607916/index.pdf.
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The purpose of this thesis is to examine the technical losses in Electric Distribution Systems, the sources of the losses, minimum levels of the losses, ways to decrease the losses and current applications in Turkey. The wrong and weak parts of the current applications are determined and emphasized. Ways to decrease losses in Distribution Systems are advised.
The energy resources in the world are decreasing rapidly. There is a rapid growth in consumption. It is a must to use existing resources in most efficient way because there is no unlimited energy source. Losses in the electric distribution systems are one of the most important subjects because the most of the technical losses in electric systems occur in the distribution systems.
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Bergensund, Andreas, Pontus Eriksson, and Oskar Häger. "District heating in Lyckebo : Investigation of distribution losses." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-253800.
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This study investigates the status and potential of the low temperature district heating system in Lyckebo, focusing on the distribution losses in the culvert system and in the heat exchangers. The Lyckebo system was built in the 1980’s as a test system with heating from a solar field and an electrical boiler. The unique features with this system were a cavern for storage of excess heat combined with a low temperature system. Today, the solar field has been substituted with two pellet boilers, but the cavern is still in service. Low temperature district heating systems are built in order to lower the losses, due to a smaller temperature difference between the medium in the culvert and the soil. This technology is used in newly built energy efficient residential areas, which makes it interesting to investigate the status of a system that was built in the 1980’s, in comparison to the possibilities of low temperature systems today. A simulation model has been developed to calculate the theoretical losses in the culvert system with production data from 2013. The total instantaneous losses in the culvert system were between 210- 280 kW and the highest losses in can be found in the secondary system. There are heat exchangers in the system that has a return temperature of approximately 8°C lower than the return temperature in the system, which leads to the conclusion that many of the exchangers in the system probably have poor energy utilization.
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Hughes, Roxana Bejarano. "Distribution of a Novel Gram Negative, Capsule-Forming Bacterium." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc500729/.
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A novel Gram negative, capsule-forming bacterium was previously isolated in Dr. G. Roland Vela's laboratory. The distribution of this bacterium in soils from various locations was investigated.
Soil samples from 188 locations around the world were examined. Isolates of the bacterium were obtained from 50 of these soils, with 48 of the isolates found in soils from the southwestern United States and northern Mexico. This suggests that this region is the natural habitat of the bacterium. The other two isolates were obtained from Madrid, Spain and Taipei, Taiwan. None were found in soils from South America or Australia. A lack of variation in morphology and physiological properties in the isolates suggests that a homogeneous population exists, even from widespread geographical locations.
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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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He, Wei. "Three essays on the risk and distribution of a portfolio's future losses." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63706.pdf.
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Williams, Kevin Vaughan Carleton University Dissertation Engineering Mechanical. "The numerical prediction of strain distribution in sheet metal forming operations." Ottawa, 1993.
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Bournival, Pierre. "Head losses and water distribution in a sandy loam soil with a subirrigation system." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64034.
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Ma, Chenije [Verfasser]. "A novel evaluation framework for energy losses in low voltage distribution grids / Chenije Ma." Kassel : kassel university press c/o Universität Kassel - Universitätsbibliothek, 2020. http://d-nb.info/1228829284/34.
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Strandet, M. L., A. Weiss, J. D. Vieira, Breuck C. de, J. E. Aguirre, M. Aravena, M. L. N. Ashby, et al. "THE REDSHIFT DISTRIBUTION OF DUSTY STAR-FORMING GALAXIES FROM THE SPT SURVEY." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621235.
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We use the Atacama Large Millimeter/submillimeter Array (ALMA) in Cycle 1 to determine spectroscopic redshifts of high-redshift dusty star-forming galaxies (DSFGs) selected by their 1.4 mm continuum emission in the South Pole Telescope (SPT) survey. We present ALMA 3 mm spectral scans between 84 and 114 GHz for 15 galaxies and targeted ALMA 1 mm observations for an additional eight sources. Our observations yield 30 new line detections from CO, [CI], [NII], H2O and NH3. We further present Atacama Pathfinder Experiment [CII] and CO mid-J observations for seven sources for which only a single line was detected in spectral-scan data from ALMA Cycle 0 or Cycle 1. We combine the new observations with previously published and new millimeter/submillimeter line and photometric data of the SPT-selected DSFGs to study their redshift distribution. The combined data yield 39 spectroscopic redshifts from molecular lines, a success rate of >85%. Our sample represents the largest data set of its kind today and has the highest spectroscopic completeness among all redshift surveys of high-z DSFGs. The median of the redshift distribution is z = 3.9 +/- 0.4, and the highest-redshift source in our sample is at z = 5.8. We discuss how the selection of our sources affects the redshift distribution, focusing on source brightness, selection wavelength, and strong gravitational lensing. We correct for the effect of gravitational lensing and find the redshift distribution for 1.4 mm selected sources with a median redshift of z = 3.1 +/- 0.3. Comparing to redshift distributions selected at shorter wavelengths from the literature, we show that selection wavelength affects the shape of the redshift distribution.
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Jeganathan, Selva. "Improving the Distribution and Retention of Drug Released From In Situ Forming Implants." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1582297937287646.
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Wallis, Kirsty K. "Investigating the ecology, diversity and distribution of cord-forming fungi in Great Britain." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:d7de00b0-74fa-473b-ac6a-c3ae61f6ac27.
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Cord-forming fungi (CFF) are an assemblage of saprotrophic fungi which can use complex foraging organs of longitudinally arranged hyphae to join up disparate substrates in a patchy resource environment. Their importance to woodlands lies, mainly, in their ability to modify nutrient cycling and soil structure. Therefore, in order to enable woodlands to continue to thrive in terms of their health and ecosystem function, it is necessary to understand the factors contributing to the establishment, success and diversity of this group. Whilst work to date on CFF has focussed on their physiology and interactions in laboratory conditions, little work has been carried out on their taxonomy and establishment/presence in the field. The work in this thesis begins to address these crucial unanswered questions in CFF ecology. By carrying out investigations at a range of scales, from phylogenetic analysis to UK wide Species Distribution Modelling, this thesis reaches a number of surprising results with potentially important implications for woodland management. This is most evident in Chapter 3 where our hypothesis that fungal communities develop over time in plantations of different woodland ages was disproved, illustrating that even 13 years after planting, fungal communities in plantations on ex-agricultural land had not begun to reach those in established ASNW. These unexpected results continue into Chapter 4, where the thesis demonstrates that dominant canopy species has a greater impact on community composition than any other woodland factor. Chapter 5 continues this theme, by showing that removal of invasive species is not always beneficial for the cord-forming fungal communities, especially if it involves removing the woody substrate. The work described, detailed and analysed in this thesis has initiated further investigations, proposed changes to woodland management practices and laid the foundations for future work relating to CFF and their role and function in British woodlands.
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Hood, L. L., N. C. Richmond, E. Pierazzo, and P. Rochette. "Distribution of crustal magnetic fields on Mars: Shock effects of basin-forming impacts." AMER GEOPHYSICAL UNION, 2003. http://hdl.handle.net/10150/623390.
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Crustal magnetic fields on Mars are inhomogeneously distributed with the strongest fields occurring over the southern highlands in a longitude sector between approximately 130°E and 240°E. Using analytic approximations and empirical scaling laws, it is estimated that much of the weakly magnetized southern highlands (i.e., that between 110°W and 130°E) was shocked to pressures exceeding 1–2 GPa during the Hellas and Argyre impacts. Possible primary remanence carriers in the martian crust include iron oxides and iron sulfides (pyrrhotite). If pyrrhotite is the main remanence carrier, extensive demagnetization of crustal regions (∼90%) may occur at shock pressures of 2 GPa or more. Thus, at least for this remanence carrier, impact shock demagnetization can potentially explain the distribution of crustal fields in the southern highlands.
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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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Trevizan, Rodrigo Daniel. "Detecção e identificação de perdas comerciais em sistemas de distribuição : metodologia baseada em floresta de caminhos ótimos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/118824.
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O sistema elétrico brasileiro possui atualmente níveis de perdas elétricas da ordem de 15%. Destes, aproximadamente a metade são provenientes das chamadas perdas comerciais (PC) que ocorrem nos sistemas de distribuição. As PC são a soma de toda energia não faturada pelas distribuidoras, á exceção das perdas técnicas. As suas causas mais frequentes são os furtos de energia elétrica, fraudes e defeitos em medidores. Os custos provenientes dessas perdas são normalmente repassados pelas distribuidoras aos consumidores regulares. No entanto, novas regulamentações do regulador brasileiro do sistema elétrico, a Agência Nacional de Energia Elétrica (ANEEL), impõem limite a esse repasse, o que cria nas concessionárias um maior incentivo para o seu combate. Entre as metodologias empregadas para a mitigação de PC, tem sido destacadas na literatura aquelas baseadas na análise das bases de dados de clientes das empresas distribuidoras com o objetivo de reconhecer padrões de clientes irregulares. Neste contexto, neste trabalho é proposto e desenvolvido um sistema de combate a PC baseado no classificador supervisionado Floresta de Caminhos Ótimos (Optimum-Path Forest, OPF). São propostas a utilização de dados categóricos e a normalização de dados como modificações nos métodos encontrados na literatura. Os testes com o sistema desenvolvido são aplicado a uma base de dados sintetizada a partir de clientes residenciais, diferentemente de trabalhos em que se utilizaram dados de consumidores comerciais e industriais. Os resultados mostram que as modificações propostas podem melhorar o desempenho do OPF. O comparativo com outros métodos de classificação reafirma a eficiência do OPF mas contesta alguns resultados presentes na literatura.The Brazilian electric power system has about 15% of losses. About a half of this amount is due to the so called commercial losses. The commercial losses are the sum of the unbilled energy less the technical losses. The commercial losses are mainly caused by electricity theft, frauds in electricity meters and electricity meter failure. The financial costs caused by these losses are included in the electricity bill, paid by the regular consumers. New regulations approved by the Brazilian regulatory agency for the electric system create a limit for this, which stimulates the investments in commercial loss mitigation by distribution companies. Among the methods used to mitigate commercial losses, those based on pattern recognition of irregular consumers within electric companies’ clients’ databases are some of the most promising. In this work, a system for commercial losses mitigation based on the supervised classifier Optimum-Path Forest (OPF) is studied and developed. Categorical data and data normalization are proposed as methods for improving classifier performance. In order to check the system performance, tests are conducted on a database derived from residential consumer data found in the literature, differently from other works which proposed data classification for commercial and industrial consumers only. The results show that using categorical data and normalization may improve OPF performance. Comparing this method with other classifiers confirms OPF’s efficiency but contests some results shown in the literature.
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SANCHEZ, VICTOR DANIEL ARMAULIA. "METHOD TO ESTIMATE THE ELECTRIC LOSSES BASED ON THE LOAD PARAMETER ALLOCATION IN MEDIUM VOLTAGE DISTRIBUTION SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=25711@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Em sistemas de distribuição de energia elétrica, um dos maiores desafios para as distribuidoras é a estimação das perdas técnicas. De acordo com a bibliografia, as perdas elétricas nas redes de distribuição em diferentes países podem variar aproximadamente de 3 porcento e 25 porcento da energia fornecida à rede, o que pode significar grandes impactos nos custos do sistema. Especificamente no Brasil, a adequada avaliação das perdas elétricas fornece informação importante para que o regulador estabeleça as tarifas de distribuição de energia elétrica. Na literatura há diversos métodos para a estimação das perdas técnicas de energia, mas devido à dificuldade na modelagem dos equipamentos do sistema, assim como a falta de informação da energia consumida pelas cargas, as estimações podem acarretar em grandes erros. Para tratar este problema, esta dissertação propõe um novo método baseado em um modelo de carga polinomial modificado para estimar as perdas elétricas, considerando medições de tensão e potência na subestação e, quando disponíveis, medições de tensão e potência demandadas pelas cargas. A contribuição principal do método proposto é o uso da informação da topologia da rede e a correlação entre a potência consumida pelas cargas e as grandezas medidas na subestação. Para detalhar e analisar o desempenho do método proposto são utilizados três sistemas elétricos. Os resultados das estimações são comparados com os resultados obtidos por outros métodos de referência encontradas na literatura e em aplicações práticas.
In electrical distribution systems, one of the greatest challenges for utilities is the estimation of technical losses. According to the literature, energy losses throughout the world s electric distribution networks may vary from country to country approximately between 3 percent and 25 percent of the electricity provided, which may cause great impacts on the electrical system costs. Specifically in Brazil, the appropriate evaluation of the energy losses provides valuable information for the regulator to establish the energy distribution tariffs. In literature, there are different ways for estimating energy losses, but due to the difficulty for modeling precisely the equipment of the system, as well as the lack of information regarding the energy consumed of each load, the energy losses estimation may lead to huge errors. To deal with this problem, it is proposed a new method based on a modified load model, taking into account the measurements of voltages and power at the substation and, when available, the measurements of voltages and power demanded by loads with meters installed. The main contribution of the proposed method is the use of the network information and the correlation between the power consumed by the loads and the voltage and power supplied by the substation. In order to detail and analyze the performance of the proposed method, three electric systems are used. The results of the estimations given by the proposed method are compared to those obtained with other methods found in literature and in practical applications.
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Holmqvist, Claes. "Mechanical modelling of blade forming and drainage of flocculated suspensions." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141.
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Ainah, Priye. "Coordinated active power reduction strategy for voltage rise mitigation in LV distribution network." Thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/28351.
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Integration of renewable energy systems by the utility, customers, and the third party into the electric power system, most especially in the MV and LV distribution networks grew over the last decade due to the liberalization of the electricity market, rising energy demand, and increasing environmental concern. The distributed rooftop PV system contributes to relieve the overall load, reduce losses, avoid conventional generation upgrade, and better matching of demand on the LV distribution network. Originally, the LV distribution network is designed for unidirectional current flow, that is from the substation to customers. However, a high penetration of rooftop solar PVs (with power levels typically ranging from 1 – 10 kW) may lead to the current flowing in the reverse direction and this could result in a sudden voltage rise. These negative impacts on the network have discouraged the distribution network operators (DNOs) to allow increased PV penetration in the LV distribution network because some customers load, and equipment are sensitive to voltage perturbation. Presently, the most applied voltage rise mitigation strategy for high rooftop solar PV penetration is the total disconnect from the LV distribution network when the voltage at the point of common coupling (PCC) goes above statutory voltage limits. However, the sudden disconnection of the PV system from the grid can cause network perturbation and affect the security of the network. This action may also cause voltage instability in the network and can reduce the lifetime of grid equipment such as voltage regulators, air conditioner etc. Due to this negative impact, different voltage rise mitigation strategies such as the active transformer with on load tap changers (OLTC), distributed battery energy storage system and reactive power support (D-STATCOM, etc.) have been used to curtail voltage rise in the distribution network. However, the implementation of D-STATCOM device on a radial LV distribution network results in high line current and losses. This may be detrimental to the distribution network. Therefore, in this thesis, a coordinated active power reduction (CAPR) strategy is proposed using a modified PWM PI current control strategy to ramp down the output power and voltage of a grid-tied voltage source inverter (VSI). In the proposed strategy, a reactive reference is generated based on the measured voltage level at the PCC using a threshold voltage algorithm to regulate the amplitude of the modulating signal to increase the off time of the high frequency signal which shut down the PV array momentary in an extremely short time and allow the VSI to absorb some reactive power through the freewheeling diode and reduce voltage. The proposed CAPR strategy was designed and simulated on a scaled down simple radial LV distribution network in MATLAB®/Simulink® software environment. The results show that the CAPR can ramp down the PV output power, reduce reverse power flow and reduce the sudden voltage rise at the point of common coupling (PCC) within ±5% of the standard voltage limit. The study also compares the performance of the proposed CAPR strategy to that of the distributed static compensator (D-STATCOM) and battery energy storage system (BESS) with respect to response time to curtail sudden voltage rise, losses and reverse power flow. The investigation shows that the D-STATCOM has the faster response time to curtail voltage rise. However, the voltage rise reduction is accompanied by high current, losses and reverse active power flow. The introduction of the BESS demonstrates better performance than the D- STATCOM device in terms of reverse power flow and losses. The CAPR strategy performs better than both D-STATCOM and BESS in terms of line losses and reverse power flow reduction.
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Calance, Marius Alexandru. "Energy Losses Study on District Cooling Pipes : Steady-state Modeling and Simulation." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-18490.
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Distributionsförluster är en viktig faktor i fjärrenergisystem. Genom att optimera förluster i sådana system, kan både ekonomiska och miljömässiga aspekter uppfyllas. Tyvärr finns det ringa information om rörförluster i fjärrkylasystem. Föreliggande studie fokuserar på förluster i ett fjärrkylanät genom att både använda ett R-nätverk och FEM simuleringsmodeller. Ett R-nätverksmodell bestående av termiska konduktanser har utvecklats genom analytiska ekvationer och simuleringar med FEM har utfört för validering av modellen. Därefter har ett fjärrkylanätverk som konstrueras i Gävle, analyserats. Undersökningen omfattar 15 olika rördiametrar i tre utföranden (dubbelrör med två symmetriska och en osymmetrisk värmeisolering) och i tre förläggningsdjup (0,8; 2 och 4 meter) för en säsong om 7 månader (April t o m Oktober). Särskilt utreds ökningen av temperaturen hos framledningsmediet, där matningsrören förlagts i en å mitt i staden om en sträcka av 1 km. Den maximala förlusten under säsongen, bland alla rörkonfigurationer, motsvarar 2 % av den totala levererade energin. Slutligen konstateras att kombinationen av isolerad framledningsrör och oisolerade returrör verkar som en gångbar investering, ekonomiskt och tekniskt, men kan inte användas i hela nätet eftersom stora delar har redan byggts med oisolerade plaströr. R-nätverksmodellen, som visades vara effektiv och pålitlig i undersökningen, kan som beräkningsverktyg, framförallt för dimensionering och för att uppskatta energiförluster.Distribution losses are a very important factor in district energy systems. By optimizing the losses in such a system, both economical and environmental aspects can be fulfilled. Unfortunately, there is few information regarding losses for district cooling systems. This study focuses on losses in district cooling networks by using both R-network and FEM simulation models. A R-network model composed of thermal conductances has been developed through analytical equations and simulations have been performed for validation. Afterwards, an in-progress construction project of a district cooling network from the city of Gävle, Sweden, is analyzed. The assessment consists of 15 pipe diameters in three configurations (two symmetric cases and one asymmetric), at three ground laying depths (0.8, 2 and 4 meters) for a duration of 7 months (April to October). A particular case in which the main distribution pipes from and to the plant are submerged in the city’s river for a distance of 1 km is investigated in order to estimate the temperature increase of the supply water. A maximum cooling loss below 2% of the total delivered energy during the season for any network configuration resulted from the calculation. Finally, the mixed pipes array seems to be a feasible investment both economically and technically but it cannot be used for the entire network spread since a part of the network has been already built with the non-insulated plastic pipes. The R-network model proved to be effective and reliable in the analysis which provides confidence that it can serve as a solid foundation for a calculation tool - primarily for design purposes and also for estimating energy loss.
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Shrestha, Pratigya. "Inverter-based Control to Enhance the Resiliency of a Distribution System." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/93764.
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Due to the increase in the integration of renewable energy to the grid, there is a critical need for varying the existing methods and techniques for grid operation. With increased renewable energy, mainly wind and photovoltaics, there is a reduction in inertia as the percentage of inverter-based resources is increasing. This can bring about an issue with the maintenance and operation of the grid with respect to frequency and voltage. Thus, the ability of inverters to regulate the voltage and frequency becomes significant. Under normal operation of the system, the ability of the inverters to support the grid frequency and voltage while following the grid is sufficient. However, the operation of the inverters during a resiliency mode, under which there is an extended outage of the utility system, will require the inverter functionality to go beyond support and actually maintain the voltage and frequency as done by synchronous machines, acting as the grid-forming inverter. This project focuses on the operation of grid forming sources based on the virtual synchronous generator to regulate the voltage and frequency in the absence of the grid voltage through decentralized control of the inverters in the distribution feeder. With the most recent interconnection standard for the distributed generation, IEEE-1547 2018, the inverter-based generation can be used for this purpose. The simulations are performed in the Simulink environment and the case studies are done on the IEEE 13 node test-feeder.Master of Science
With the increase in the renewable energy sources in the present grid, the established methods for the operation of the grid needs to be updated due to the changes that the large amount of renewable energy sources bring to the system. Due to the While the conventional resources in the power system was mainly synchronous generators that had an inherent characteristic for frequency support and regulation due to the inertia this characteristic can be lacking in many of the renewable energy sources that are usually inverter-based. At present, the commonly adapted function for the inverters is to follow the grid which is suitable in case of normal operation of the power system. However, during emergency scenarios when the utility is disconnected and a part of the system has to operate independently the inverters need to be able to regulate both the voltage and frequency on their own. In this project the inverter-based control, termed as the virtual synchronous generator, has been studied such that it mimics the well-established controls for the conventional generators so that the inverter-based renewable resource appears similar to the conventional generator from the point of view of the grid in terms of the electrical quantities. The utilization of this type of control for operation of a part of the feeder with each inverter-based resource controlling its output in a decentralized manner is studied. The controls try to mimic the established controls for conventional synchronous machine and use it for maintain operation of the system with inverters.
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Freitas, Luiz Eduardo MagalhÃes de. "Operational risks - an application of the method of distribution of aggregate losses: a study of case in financial institution." Universidade Federal do CearÃ, 2005. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1830.
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Universidade Federal do CearÃThis paper demonstrates the application of stochastic process Aggregate Loss Distribution Approach for measure of operational risk in a financial institution in according with the minimal requirement of Basel New Adequacy Capital Framework. The mesure uses the historical behaviour of specific operational losses wich happened in the period from 2001,jan to 2004, dec, caused by frauds in and out the company. The process involves the probability distributions fit to frequency and severity historic loss data, the adjustment validation through the application statistical tests and the compound of frequency and severity distributions for production of aggregate yearly loss distribution using Monte Carlo simulation. It approaches either a backtest model for result validation and the stress scenarios development for impacts verification in the capital allocation. This paper clarifies the application of Aggregate Loss Distribution Approach to mesure operational risks, with objective features of validation at every process stages as well as its use as a tool of evaluation from the extreme risk efects and focus in risks mitigation actions through the development scenarios for stresstesting.
Esta dissertaÃÃo demonstra a aplicaÃÃo do processo estocÃstico MÃtodo de DistribuiÃÃo de Perdas Agregadas para mensuraÃÃo de riscos operacionais em uma instituiÃÃo financeira, segundo os requisitos mÃnimos do Novo Acordo de Capital da BasilÃia. A mensuraÃÃo tem por objeto o comportamento histÃrico de perdas operacionais especÃficas, ocorridas no perÃodo de jan/2001 a dez/2004 e decorrentes de fraudes de origem interna e externa à empresa. O processo envolve o ajuste de distribuiÃÃes de probabilidade aos dados de perdas histÃricas, freqÃÃncia e severidade, a validaÃÃo do ajuste mediante a aplicaÃÃo de testes estatÃsticos e a composiÃÃo de distribuiÃÃes de freqÃÃncia e severidade para geraÃÃo da distribuiÃÃo das perdas anuais agregadas, atravÃs de simulaÃÃo de Monte Carlo. Aborda, ainda, um modelo de backtest para validaÃÃo dos resultados e o desenvolvimento de cenÃrios de stress para verificaÃÃo de impactos na alocaÃÃo de capital. Evidencia-se, nesse trabalho, a aplicabilidade do MÃtodo de DistribuiÃÃo de Perdas Agregadas na mensuraÃÃo de riscos operacionais, com caracterÃsticas objetivas de validaÃÃo em todas as etapas do processo, e a sua utilizaÃÃo como instrumento de avaliaÃÃo dos efeitos de riscos extremos e de direcionamento de aÃÃes mitigadoras de riscos â atravÃs do desenvolvimento de cenÃrios para teste de stress.
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Andersson, Oscar. "Influence of primary precipitate shape, size volume fraction and distribution in PM tool steels on galling resistance." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-37813.
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In sheet metal forming (SMF), the major failure reason is galling. Galling is a process of different wear stages that leads to destruction of both the forming tool and the sheet metal working piece and is, because of that, of big economic importance for the SMF industries. Therefore, investigations and researches about how tool steels microstructure affect the tool steels galling resistance is of high priority. In the present work, different carbide properties were studied to find out how their properties affected the tool materials galling resistance. The investigated carbide properties were: Shape and size of the carbides Carbide volume fraction Carbide distribution in the microstructure The investigation included three tools, all made of the PM tool steel S390, that were heattreated differently in order to achieve different carbide properties but still maintain the same hardness. The tools were galling tested in a slider-on-flat-surface (SOFS) tribometer to determine their galling resistances. In a scanning surface electron microscope (SEM) the tools galling marks were analyzed to find explanations for the SOFS tribometer results and the connection to the tools different carbide properties. The investigations most galling resistant tool was the tool that had the microstructure with largest carbides which were distributed at grain boundaries and the second highest carbide volume fraction among the investigated tools.
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Jensen, Maria Louise Strandet [Verfasser]. "The redshift distribution and dust properties of dustz star-forming galaxies at high redshift / Maria Louise Strandet Jensen." Bonn : Universitäts- und Landesbibliothek Bonn, 2018. http://d-nb.info/1160594287/34.
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Méffe, André. "Metodologia para cálculo de perdas técnicas por segmento do sistema de distribuição." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-19032002-131948/.
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Este trabalho tem por objetivo propor uma nova metodologia para o cálculo das perdas técnicas de energia e demanda por segmento do sistema de distribuição. As perdas técnicas foram divididas em oito segmentos: medidor de energia, ramal de ligação, rede secundária, transformador de distribuição, rede primária, subestação de distribuição, sistema de alta tensão e outros. Neste último segmento, foram incorporadas as parcelas referentes a equipamentos (capacitores, reguladores de tensão, etc), perdas em conexões, corrente de fuga em isoladores, etc. Desenvolveu-se um sistema computacional, para uso em microcomputador, que conta com dois módulos principais. O primeiro módulo destina-se ao cálculo das perdas técnicas em redes específicas. O cálculo é feito de forma hierárquica, por exemplo, selecionada uma subestação específica, são calculadas as perdas na subestação e em todos os componentes a jusante (redes primárias, transformadores de distribuição, redes secundárias, ramais de ligação e medidores de energia). As perdas técnicas, em termos de energia e demanda, são obtidas por meio de cálculo elétrico específico para os segmentos envolvidos, com a utilização dos dados cadastrais da rede, dados de faturamento e curvas de carga típicas por classe de consumidor e tipo de atividade desenvolvida. Com a aplicação deste módulo para todo o sistema da empresa, ou para uma parcela representativa, obtém-se um índice percentual de perda de energia para cada segmento. Estes índices são transferidos para o segundo módulo, que tem por objetivo efetuar o balanço de energia do sistema. A partir dos dados de energia nos pontos de suprimento, da energia total faturada mensalmente e dos índices de perdas por segmento, são obtidos os montantes de energia de perdas em cada segmento do sistema e uma avaliação das perdas não técnicas. O trabalho ainda apresenta um exemplo de aplicação, em sistema de distribuição real, mostrando os resultados obtidos, e termina apresentando as principais vantagens da metodologia. Os resultados obtidos com a nova metodologia são comparados com os resultados obtidos com outras metodologias.This work focuses on the development of a new methodology for calculating technical losses within the different segments of the electric distribution system. In order to evaluate technical losses the electrical system was divided into eight segments: energy meter, customer connections, secondary feeder, distribution transformer, primary feeder, distribution substation, high voltage system and another segment that represents other technical losses. The latter comprises losses in equipment such as capacitors and voltage regulators as well as losses in electric connections, isolators, etc. A computational system was developed and it comprises two modules. The first one is intended to calculate technical losses in specific networks. The calculation is made in a hierarchical manner. If a distribution substation is selected for the calculation, the losses in that substation and the losses in all components downstream are calculated. The technical losses, in terms of energy and demand, are obtained by utilizing network topological data, consumed energy data and typical load curves per customer class and activity type. An energy losses index, calculated as a percentage of the supplied energy, is obtained for each segment by applying this module to the entire utilitys power system or in a representative part of it. These values are transferred to the second module, which has the objective of determining the overall energy balance. Technical and non-technical losses, in terms of energy, in each segment are obtained by utilizing the total amount of energy supplied to the system, energy consumed and energy losses indices per segment. This work shows the results obtained by applying the computational tool to a real distribution system. Such results are compared with the ones obtained by using other methodologies, and the main advan ages of this new methodology are outlined.
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Pfunder, Monika. "Genetic variation, spatial distribution, and reproductive biology of pseudoflower-forming rust fungi (Uromyces pisi and relatives) on Euphorbia cyparissias /." [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13331.
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Jones, Mackenzie L., Ryan C. Hickox, Christine S. Black, Kevin N. Hainline, Michael A. DiPompeo, and Andy D. Goulding. "THE INTRINSIC EDDINGTON RATIO DISTRIBUTION OF ACTIVE GALACTIC NUCLEI IN STAR-FORMING GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621376.
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An important question in extragalactic astronomy concerns the distribution of black hole accretion rates of active galactic nuclei (AGNs). Based on observations at X-ray wavelengths, the observed Eddington ratio distribution appears as a power law, while optical studies have often yielded a lognormal distribution. There is increasing evidence that these observed discrepancies may be due to contamination by star formation and other selection effects. Using a sample of galaxies from the Sloan Digital Sky Survey Data Release 7, we test whether or not an intrinsic Eddington ratio distribution that takes the form of a Schechter function is consistent with previous work suggesting that young galaxies in optical surveys have an observed lognormal Eddington ratio distribution. We simulate the optical emission line properties of a population of galaxies and AGNs using a broad, instantaneous luminosity distribution described by a Schechter function near the Eddington limit. This simulated AGN population is then compared to observed galaxies via their positions on an emission line excitation diagram and Eddington ratio distributions. We present an improved method for extracting the AGN distribution using BPT diagnostics that allows us to probe over one order of magnitude lower in Eddington ratio, counteracting the effects of dilution by star formation. We conclude that for optically selected AGNs in young galaxies, the intrinsic Eddington ratio distribution is consistent with a possibly universal, broad power law with an exponential cutoff, as this distribution is observed in old, optically selected galaxies and X-rays.
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Shane, William T. "Persistence of Spore Forming Bacteria on Drinking Water Biofilm and Evaluation of Decontamination Methods." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1205164893.
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Penin, Carlos Alexandre de Sousa. "Combate, prevenção e otimização das perdas comerciais de energia elétrica." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-14082008-092248/.
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As perdas de energia elétrica devidas a furtos e fraudes, também chamadas de Perdas Não-Técnicas (PNT) ou Perdas Comerciais, têm sido matéria prioritária das empresas concessionárias de distribuição de energia elétrica, bem como dos órgãos reguladores, tanto pelo seu crescimento nos últimos anos quanto pelo seu impacto no sistema elétrico brasileiro. As formas de fraude são as mais variadas possíveis, o que gera enormes dificuldades para as concessionárias. Este trabalho tem como objetivo o estudo do problema das PNT utilizando-se de uma abordagem multidisciplinar, que analisa a experiência tanto de concessionárias no Brasil como no exterior. O trabalho discute as melhores práticas para mitigação das mesmas e propõe melhorias nos processos de combate e de prevenção, e nos procedimentos legais para recuperação de receitas, apoiados sobre uma cuidadosa contextualização regulatória. Chamase a atenção para a diversidade sócio-econômica nacional, compara-se com diversos exemplos internacionais, e propõe-se identificar os aspectos mais relevantes a serem considerados na regulação sobre o tema, discutindo procedimentos e metodologias para o equacionamento do montante de recursos a serem aplicados pelas companhias distribuidoras para a adequada redução dessas perdas de energia. Observa-se que grande parte das PNT tem origem em questões de cunho social. O Estado pode e deve estabelecer políticas para resolver tais questões, possibilitando a universalização do acesso e subsidiando o fornecimento de energia elétrica. Não fez parte dessa pesquisa discutir se estes instrumentos são suficientes ou devem ser aprimorados, mas sim analisar amplamente a questão das PNT com base nos condicionantes regulatórios atuais, que obrigam as concessionárias a reduzir estas perdas visando entre outros a modicidade tarifária dos consumidores regulares.The electric power losses due to thefts and frauds, also called Non technical Losses (NTL), have been priority matter for concessionary companies of electric power distribution, as well as for government regulatory agencies, not only due to rapid growth over the past years but also due to its impact on Brazilian electrical system. There is a wide range of possible types and methods of frauds, causing enormous difficulties to licensed companies. The objective of this work is to study the problem of NTL using a wide approach, analyze the experience of dealerships in Brazil and abroad, discuss the best practices for mitigation of those losses and propose improvements in the combat and prevention processes, and the legal procedures for recovery of incomes, leaning on a careful regulatory context. This study draws attention to Brazil\'s socioeconomic diversity, comparing it to various international examples, and intends to identify the most relevant aspects that must be considered on the theme, discussing procedures and methodologies for the equation of the amount of resources to be applied by distributing companies to achieve the appropriate reduction of NTL. A large part of the commercial losses has its origin in issues of social stamp. The State owes and can establish policies to solve such issues, making possible the access to electric power supply for all consumers. It was not part of this research to discuss if these instruments are enough, but to analyze the issue of the commercial losses thoroughly based in the regulatory policies that push dealerships to reduce NTL objecting reasonable regular consumers\' tariff.
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Zavadzkis, Lukas. "Skirstomųjų tinklų galios nuostolių skaičiavimo metodų palyginimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050614_162126-59320.
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Calculation methods of electric power loss in 10 kV distribution network were analyzed in this study. It was examined what influence to power loss calculations has the cable resistance dependency on temperature and cable load. Voltage losses dependency on step-down transformer load, active and reactive power coefficients cosφ and sinφ was also an object of this research. It was intended to analyze comparative power loss dependences for various cross-section 10 kV cables too. Electric power loss calculations according to average load current are made for the real distribution network.
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Dresch, Rodolfo de Freitas Valle. "Análise do efeito da modelagem da carga nas estimativas de perdas elétricas em sistemas de distribuição." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/103754.
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As perdas elétricas, que no Brasil giram em torno de 14,4%, são prejudiciais ao desempenho técnico e financeiro das concessionárias de energia elétrica, principalmente em um cenário de uma eminente crise energética e alta regulação. A mitigação das perdas elétricas está diretamente relacionada com sua correta estimação. Para operar um sistema de energia elétrica, é de fundamental importância definir a correta modelagem dos elementos do sistema. As metodologias de estimação das perdas de energia, para sistemas de distribuição, vigentes não levam em conta possíveis erros na correta modelagem das cargas conectadas. Desta forma, este trabalho tem o objetivo de analisar a influência causada pela utilização dos modelos de carga, na estimação das perdas elétricas em sistemas de distribuição. Esta análise abrange as metodologias de fluxo de carga backward-forward sweep por soma de corrente, por soma de potência e Newton-Raphson. A perda de energia é calculada pela diferença entre a energia injetada no sistema, menos a energia entregue. O estudo de caso é realizado em um sistema de distribuição teste de 13 barras da IEEE. No caso proposto, são realizados cálculos das perdas de energia para o sistema de distribuição, considerando diferentes modelos de carga. Desta maneira, o trabalho estimou a diferença no cálculo das perdas para cada tipo de modelo de carga, em relação a perdas calculadas com o padrão original das cargas. Outro ponto analisado foi o desempenho das metodologias de fluxo de carga, frente à alteração dos modelos de carga. Os resultados demonstram que a alteração dos modelos de carga influência a estimação das perdas elétricas nos sistemas de distribuição, e o desempenho dos fluxos de carga.Electrical losses, which in Brazil are around 14.4%, are harmful to the technical and financial performance of electric utilities, especially in a scenario of an imminent energy crisis and high regulation. Mitigation of electrical losses is directly related to its correct estimation. To operate an electric power system, it is of fundamental importance to define the correct model of the system elements. The methodologies for estimating energy losses, for the existing distribution systems, do not take into account possible errors in the correct model of connected loads. Thus, this study aims to examine the influence caused by the use of different load models, in the estimation of electrical losses in distribution systems. This analysis covers the backward-forward sweep load flow methodologies by the sum of current, by the sum of power and Newton-Raphson. The energy loss is calculated by the difference between the energy injected into the system, minus the energy delivered. The case study is performed on the IEEE 13 Node Test Feeder. In the proposed case, calculations of energy losses in the distribution system are performed considering different load models. Therefore, the study has estimated the difference in the calculation of energy loss for each type of load model, for the losses calculated with the original pattern of loads. Another point discussed is the performance of load flow methodologies, related to the change of load models. The results have shown that the change in load models influence the estimation of electrical losses in distribution systems and in the performance of load flows.
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Holmqvist, Claes. "Modelling of the pressure distributions in twin-wire blade formers." Licentiate thesis, KTH, Mechanics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1490.
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During papermaking, the internal structure of the fibrenetwork constituting the paper is to a dominating extentdetermined in the forming zone of the paper machine. Thisthesis is aimed at studying the pressure distribution in bladeforming sections, which is commonly considered to be a keyquantity of the process.
Previous work has provided insight into the physics ofdifferent devices employed in blade forming. However, there hasbeen a lack of models enabling studies of the effects of theinteraction between different components on the pressuredistribution. In the thesis, a model is presented for a genericblade forming section consisting of three blades. The positionsof two of the blades are fix, and in between them is located asuction box. The third blade is applied by a prescribed forceto the opposing wire, in a position facing the suction box. Themodel admits the study of the interaction between the pulsesfrom the different blades in the blade/counterbladeconfiguration, and between the pulses and one-sidedsuction.
The wires are modelled as tensioned and perfectly flexibleEuler-Bernoulli beams of negligible mass. The suspension istreated like an inviscid fluid. Consideration is taken to theinfluence of fibre deposition on the permeability of thefabrics. By assuming the ratio between the length scales in thethickness direction and the machine direction to be small, aquasi one-dimensional model is obtained.
For maximum flexibility, the model domain is divided intomodules. Each module is solved individually using a finitedifference based discretisation. The solutions for thedifferent modules are matched with each other iteratively.
A comparison with published results for a single bladeindicates that the model can be used to obtain qualitativelycorrect predictions of the pressure distribution. New resultsinclude a series of calculations showing the non-trivialinteraction between the pressure pulses when the blades arepositioned successively closer together, the effects of suctionon the pressure pulse generated by a blade applied to theopposing wire, and how blades of modest curvature do notnecessarily stay in contact with the fabric along their fullwidth and the implication of this on the pressure gradient.
Descriptors:fluid mechanics, blade forming, pressuredistribution, suction, interaction, permeable fabric,modules
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Bazzi, Ali, and Andreas Angelou. "Simulation of the anisotropic material properties in polymers obtained in thermal forming process." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Produktutveckling, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-40792.
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In an attempt to improve the quality in finite element analysis of thermoformed components, a method for predicting the thickness distribution is presented. The strain induced anisotropic material behaviour in the amorphous polymers of concern is also taken into account in the method. The method comprises of obtaining raw material data from experiments, followed by a simulation of the vacuum thermoforming process where hyperelastic material behaviour is assumed. The theory of hyperelasticity that was applied was based on the Ogden model and implemented in the FE-software LS-DYNA. Material behaviour from thermoformed prototypes is examined by experiments and implemented together with the mapped results from the thermoforming simulation in a succeeding FE-model. For the latter, the three-parameter Barlat model was suggested, giving the possibility to account for anisotropic material behaviour based on an initial plastic strain.
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Lucini, Filipe Rissieri. "Método para identificação de quedas de consumo atípicas em unidades consumidoras de energia elétrica." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/26533.
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Esse trabalho tem por objetivo aprimorar a principal atividade das empresas de distribuição no que diz respeito ao combate às perdas comerciais: as inspeções em campo às unidades consumidoras (UCs). Para tanto, é feita a proposição de um método para identificar quedas de consumo atípicas dentro do universo de faturamento de UCs de uma concessionária de energia elétrica. A proposta está fundamentada na análise dos registros históricos de consumo, de modo que os dados considerados atípicos possam ser indicados e as UCs ranqueadas de acordo com a prioridade para as inspeções em campo. Para tanto, propõe-se a utilização combinada de técnicas de previsão de demanda e de estatísticas robustas. A validade do método foi verificada através de um estudo de caso em uma empresa de distribuição de energia elétrica do sul do Brasil. Através do estudo de caso, concluiu-se que o método é capaz de identificar quedas de consumo atípicas, tendo identificado satisfatoriamente 89,38% dos casos avaliados. Ao final do trabalho, são apresentadas sugestões de estudos complementares, de modo a aperfeiçoar o desempenho do método.This study aims to enhance the main business of distribution companies regarding to the efforts to avoid non-technical losses, that means, field inspections at the consumer units (CUs). For that, the proposition of an algorithm to identify atypical consumption falls within the universe of PAs billing of an electric facility is made. The proposal is based on the analysis of historical records of consumption, so that the data which are considered atypical can be indicated and the CUs ranked according to their priority for inspections in the field. Combined techniques of demand forecasting and statistics robust are proposed. The validity of the algorithm was verified through a case study in an electric power distribution facility in southern Brazil. Through the case study, it was concluded that the algorithm is able to identify atypical consumption falls, and satisfactorily 89.38% of the cases was identified. At the end of this paper, suggestions for further studies in order to improve the performance of the algorithm are presented.
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Blasi, Bronson Richard. "DC microgrids: review and applications." Kansas State University, 2013. http://hdl.handle.net/2097/16823.
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Master of ScienceDepartment of Architectural Engineering and Construction Science
Fred Hasler
This paper discusses a brief history of electricity, specifically alternating current (AC) and direct current (DC), and how the current standard of AC distribution has been reached. DC power was first produced in 1800, but the shift to AC occurred in the 1880’s with the advent of the transformer. Because the decisions for distribution were made over 100 years ago, it could be time to rethink the standards of power distribution. Compared to traditional AC distribution, DC microgrids are significantly more energy efficient when implemented with distributed generation. Distributed generation, or on-site generation from photovoltaic panels, wind turbines, fuel cells, or microturbines, is more efficient when the power is transmitted by DC. DC generation, paired with the growing DC load profile, increases energy savings by utilizing DC architecture and eliminating wasteful conversions. Energy savings would result from a lower grid strain and more efficient utilization of the utility grid. DC distribution results in a more reliable electrical service due to short transmission distances, high service reliability when paired with on-site generation, and efficient storage. Occupant safety is a perceived concern with DC microgrids due to the lack of knowledge and familiarity in regards to these systems. However, with proper regulation and design standards, building occupants never encounter voltage higher than 24VDC, which is significantly safer than existing 120VAC in the United States. DC Microgrids have several disadvantages such as higher initial cost due, in part, to unfamiliarity of the system as well as a general lack of code recognition and efficiency metric recognition leading to difficult certification and code compliance. Case studies are cited in this paper to demonstrate energy reduction possibilities due to the lack of modeling ability in current energy analysis programs and demonstrated energy savings of approximately 20%. It was concluded that continued advancement in code development will come from pressure to increase energy efficiency. This pressure, paired with the standardization of a 24VDC plug and socket, will cause substantial increases in DC microgrid usage in the next 10 years.
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Palo, Paulo Rogério. "Avaliação da eficácia de modelos de simulação hidráulica na obtenção de informações para diagnóstico de perdas de água." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-27092010-104217/.
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Atualmente a avaliação das perdas de água, nos sistemas de distribuição, é feita com base em equações empíricas, que utilizam informações, agrupadas e totalizadas, de uma área. Isto torna necessária sua subdivisão em frações cada vez menores, na busca da fração mais crítica. Neste trabalho, é apresentada uma avaliação da eficácia do uso de modelos de simulação hidráulica na obtenção das informações necessárias para a elaboração de um diagnóstico de perdas de água, com uma metodologia prática para o uso de modelos com este objetivo. Apresenta uma classificação dos trechos de rede em três categorias A, B e C, que facilita a priorização dos trechos mais críticos facilitando a análise por meio de gráficos de pareto e mapas temáticos. Demonstra que a adoção da simulação hidráulica no estudo das causas de perdas de água, nos sistemas de abastecimento, é uma ferramenta eficaz e permitirá às empresas de saneamento, uma melhoria na gestão operacional, que garante a sustentabilidade da empresa, a economia dos recursos humanos, econômicos, e principalmente, os hídricos.Currently water losses evaluation in distribution systems, is based on empirical equations using information, grouped and totaled, covering whole area. Thus, becomes necessary to subdivide the area into smaller and smaller fractions, searching for the most critical part. This study presents, the effectiveness evaluation of the hydraulic simulation models, use to obtain the information necessary in elaboration diagnosis of water losses, with a practical methodology for using models for this purpose. Shows a pipe classification in three categories A, B and C, its began possible analyses with pareto graphics and thematic maps. Demonstrates that hydraulic simulation adoption is an effective tool in the study of water loss in supply systems. It will allow companies an operational management improvement, ensuring the sustainability of the business and economics of human, financial, and especially, water resources.
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Silva, Cleyton Oliveira da. "Modelagem de rede de distribuição de água com ênfase no controle de perdas." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/5527.
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The present study aims dissertative modeling and calibration of a real distribution system water, with emphasis on the identification of water losses. The case study was the supply system of Juatama community in Quixadá, located in the central region of the state of Ceará. The distribution network under study was recently installed and is operating with stability, which enabled the development of a model that successfully describes the real system. The calibration process was carried out through LenhsCalibra application, which uses an optimization algorithm based on the technique of genetic algorithms. The program allowed multivariate calibration, including how to search the demand variables and the roughness of pipes, whose values were adjusted using simulations from the actual flow levels and pressures. The calibrated model system showed satisfactory results, and identify the record of discharges used for cleaning of the network and network points higher than those with demands effectively, are consumed by customers.
O presente estudo dissertativo tem por objetivo a modelagem e calibração de um sistema de distribuição de água real, com ênfase na identificação das perdas de água. O estudo de caso foi o sistema de abastecimento da comunidade de Juatama, em Quixadá, localizada na região central do Estado do Ceará. A rede de distribuição em estudo foi instalada recentemente e vem operando com estabilidade, o que possibilitou o desenvolvimento de um modelo que descreve satisfatoriamente o sistema real. O processo de calibração foi realizado por meio do aplicativo LenhsCalibra, que utiliza um algoritmo de otimização baseado na técnica de algoritmos genéticos. O programa possibilitou a calibração multivariada, incluindo como variáveis de busca a demanda e a rugosidade das tubulações, cujos valores foram ajustados através de simulações a partir dos níveis de vazão e pressões reais. O modelo calibrado do sistema apresentou resultados satisfatórios, além de identificar o registro de descargas utilizadas para limpeza da rede e pontos na rede com demandas superiores às que, efetivamente, são consumidas pelos clientes.
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Петровський, Михайло Васильович, Михаил Васильевич Петровский, Mykhailo Vasylovych Petrovskyi, and М. О. Сокольнікова. "Формування моделі для розрахунку втрат електроенергії на базі програмного комплексу АСКОЕ." Thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/67907.
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Останнім часом через ряд причин як технічних, так і економічних, втрати електроенергії в розподільчих мережах є досить істотними і це незважаючи на загальну тенденцію до зниження електроспоживання. Виходячи з цього, з’явилася нагальна потреба в формуванні моделі для розрахунку втрат електроенергії саме в розподільчих мережах.
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Mužila, Martin. "Náhrada parovodu horkovodem v systému centrálního zásobování teplem teplárny Martinská teplárenská, a.s." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231255.
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The work is focused on area of exchanging steam distribution net for hot water one, in central distribution net of Martin’s heating plant. The main subject, which talks about pros and cons in this exchange process, is determination of heat losses which are created on heat distribution net during different operating status. These heat losses are calculated and on their basis some conclusions are concluded. Moreover, new heat exchanger is designed for certain conditions and also mathematical model of distribution net is created, which is suitable for checking different operating status. As a result of the work is technic’s and economic’s analysis of this project.
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Іваніцький, Сергій Борисович. "Моделювання режиму роботи розподільної електричної мережі з джерелами розосередженої генерації." Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2019. https://ela.kpi.ua/handle/123456789/28482.
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Дипломна робота складається з пояснювальної записки та графічної частини. Пояснювальна записка виконана на 74 сторінках формату А4, яка включає в себе 33 рисунки, 13 таблиць, 16 джерел використаної літератури. Графічна частина містить 3 аркуші технічних креслень форматом А1. Ця робота присвячена вивченню впливу розосередженої генерації на режимні параметри мережі. В роботі також розглянуто проблеми функціонування розподільних електричних мереж з джерелами розосередженої генерації. Проведено розробку методу для визначення оптимального місця підключення джерел розосередженого генерування до електричної мережі та визначення оптимальної потужності генерації.
Режими роботи електричної мережі розраховано в програмному середовищі «PowerFactory», що використовує модифікований метод Ньютона-Рафсона для виконання розрахунку усталених режимівThesis consists of an explanatory note and graphical part. Explanatory note made 74 pages of A4, which includes 33 figures, 13 tables and 16 sources of literature. The graphical part contains 3 sheets of A1 technical drawings.The paper is dedicated to the exploring of the effects of distributed generation on the network parameters. The problems of functioning of distributed electric networks with distributed generation sources are also considered. A method has been developed to determine the optimal location for connecting sources of distributed generation to the electrical network and to determine the optimal generation power. Modes electrical network designed software environment in «PowerFactory», using a modified Newton-Raphson method for calculating the steady performance
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Dahmen, Volker [Verfasser], George [Akademischer Betreuer] Iliakis, and Jürgen [Akademischer Betreuer] Thomale. "I-125-labeled Triplex-Forming-oligonucleotides : Studies on intracellular distribution, cytotoxicity and on gene expression alterations of target genes / Volker Dahmen. Gutachter: Jürgen Thomale. Betreuer: George Iliakis." Duisburg, 2013. http://d-nb.info/1042899649/34.
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Vanet, Emmanuelle. "Distribution de l'intelligence et approche hétérarchique des marchés de l'énergie distribués dans les Smart Grids." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT112/document.
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En lien étroit avec le projet européen DREAM, le sujet de thèse s’intègre dans les évolutions opérationnelles des réseaux de distribution de demain intégrant de larges quantités d'énergies renouvelables. Un contrôle centralisé de l'ensemble des acteurs est, certes globalement optimal mais complexe et peu fiable. L'étude porte sur la faisabilité d'un contrôle distribué, auto-adaptatif et temps réel des ressources locales et des composants du réseau. La piste principale explorée correspond à des agents autonomes qui peuvent construire des structures collaboratives ad-hoc suivant les besoins du réseau. Ces structures collaboratives adresseront divers modes de fonctionnement, du marché de l'énergie J-1 à infraday au marché d'ajustement (services systèmes) et au contrôle local (fréquence et auto-cicatrisation)In close relationship with the European project DREAM, this doctoral thesis focus on operational evolutions in tomorrow’s distribution networks wich will integrate a larger amount of distributed renewable resources. A centralized control of all the entities (from controllable loads to embedded generators) is overall optimal but complex and not so reliable. This study addresses the feasibility of a distributed control, autonomous, self-learning and real time operation of local resources and network’s components. The main concern to explore will be the creation of ad-hoc federations of agents that will flexibly adjust their hierarchy to current needs. These collaborative structures will use different coordination strategies ranging from market-based transactions, to balancing optimization market (ancillary services) and to local control (frequency control and self-healing)
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Fiala, Martin. "Elektrické sítě využívající stejnosměrné napětí do 1000 V." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241980.
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This master´s thesis deals with the proposal of DC low voltage network at a voltage level of 1000 V DC in Praskolesy u Mrakotina village. Direct distribution will be realized only at the terminal, which will power the village. Next part of this thesis is theoretical and its main focus is description of both DC and AC distribution systems. The proposed DC grid will use existing distribution grid. The thesis further describes the problems of long terminals in low voltage distribution systems and electrical installation in buildings. The result of this work is a comparison of the losses between AC and the proposed DC system. The last part deals with economical evaluation and technical solution for the proposed network variant, including their advantages and disadvantages.
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Gladkikh, Egor. "Optimisation de l'architecture des réseaux de distribution d'énergie électrique." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT055/document.
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Pour faire face aux mutations du paysage énergétique, les réseaux de distribution d'électricité sont soumis à des exigences de fonctionnement avec des indices de fiabilité à garantir. Dans les années à venir, de grands investissements sont prévus pour la construction des réseaux électriques flexibles, cohérents et efficaces, basés sur de nouvelles architectures et des solutions techniques innovantes, adaptatifs à l'essor des énergies renouvelables. En prenant en compte ces besoins industriels sur le développement des réseaux de distribution du futur, nous proposons, dans cette thèse, une approche reposant sur la théorie des graphes et l'optimisation combinatoire pour la conception de nouvelles architectures pour les réseaux de distribution. Notre démarche consiste à étudier le problème général de recherche d'une architecture optimale qui respecte l'ensemble de contraintes topologiques (redondance) et électrotechniques (courant maximal, plan de tension) selon des critères d'optimisation bien précis : minimisation du coût d'exploitation (OPEX) et minimisation de l'investissement (CAPEX). Ainsi donc, les deux familles des problèmes combinatoires (et leurs relaxations) ont été explorées pour proposer des résolutions efficaces (exactes ou approchées) du problème de planification des réseaux de distribution en utilisant une formulation adaptée. Nous nous sommes intéressés particulièrement aux graphes 2-connexes et au problème de flot arborescent avec pertes quadratiques minimales. Les résultats comparatifs de tests sur les instances de réseaux (fictifs et réels) pour les méthodes proposées ont été présentésTo cope with the changes in the energy landscape, electrical distribution networks are submitted to operational requirements in order to guarantee reliability indices. In the coming years, big investments are planned for the construction of flexible, consistent and effective electrical networks, based on the new architectures, innovative technical solutions and in response to the development of renewable energy. Taking into account the industrial needs of the development of future distribution networks, we propose in this thesis an approach based on the graph theory and combinatorial optimization for the design of new architectures for distribution networks. Our approach is to study the general problem of finding an optimal architecture which respects a set of topological (redundancy) and electrical (maximum current, voltage plan) constraints according to precise optimization criteria: minimization of operating cost (OPEX) and minimization of investment (CAPEX). Thus, the two families of combinatorial problems (and their relaxations) were explored to propose effective resolutions (exact or approximate) of the distribution network planning problem using an adapted formulation. We are particularly interested in 2-connected graphs and the arborescent flow problem with minimum quadratic losses. The comparative results of tests on the network instances (fictional and real) for the proposed methods were presented
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Zamboni, Lucca. "Otimização da topologia de circuitos de distribuição de energia elétrica usando algoritmos inspirados no comportamento de formigas." Universidade Presbiteriana Mackenzie, 2007. http://tede.mackenzie.br/jspui/handle/tede/1452.
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Previous issue date: 2007-03-19Ant colonies can be considered a multi-agent system, where each agent (ant) works independently by simple rules. Algorithms based on the behavior of ant colonies have been used to solve optimization problems, because in the search for food ants tend to create the shortest (optimum) path between the nest and the food source. In this work, ant inspired algorithms are used in the optimization of the topology of electric energy distribution networks. The algorithm performance is investigated in function of its parameter values. Experiments in hypothetical and actual distribution systems are performed.
Colônias de formigas podem ser consideradas um sistema multi-agente, em que cada agente (formiga) opera independentemente por regras simples. Algoritmos baseados no comportamento de colônias de formigas têm sido usados para resolver problemas de otimização, pois, na procura por alimento, as formigas tendem a estabelecer a rota mais curta (ótima) entre o formigueiro e a fonte de alimento. Neste trabalho, usam-se algoritmos inspirados em formigas na otimização da topologia de circuitos de distribuição de energia elétrica. O desempenho do algoritmo é investigado em função dos valores dos seus parâmetros. Realizam-se experimentos em sistemas de distribuição hipotéticos e realistas.
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Michel, André Bernardes. "Alocação de bancos de capacitores e reguladores de tensão usando otimização por metas considerando geração distribuída." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/118829.
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Sistemas de Distribuição de Energia Elétrica (SDEE) estão, pelas próprias condições de funcionamento, sujeitos a perdas de energia e quedas nos níveis de tensão. Uma das formas de reduzir as perdas e ao mesmo tempo melhorar o perfil de tensão do SDEE consiste na utilização de bancos de capacitores e reguladores de tensão ao longo dos alimentadores. Para isto a alocação ótima destes equipamentos torna-se de fundamental importância, logo este trabalho tem por objetivo a utilização de um método quadrático de programação por metas multiobjetivo para a ótima alocação desses equipamentos visando a redução de perdas (meta 1) com o menor custo de investimento (meta 2) sujeito a restrições do fluxo de potência, limites técnicos de operação, mudança no controle dos capacitores chaveados e dos taps dos reguladores de tensão. O constante aumento na penetração da geração distribuída traz novos desafios para o controle e a operação dos SDEE. A metodologia proposta considera os efeitos destas fontes de geração e os seus impactos na alocações ótima dos bancos de capacitores e reguladores de tensão. Com o intuito de resolver o problema de otimização em programas comerciais como Gurobi e Cplex uma metodologia linear de cálculo de fluxo de potência é utilizada. Os algoritmos foram desenvolvidos no software Matlab, e posteriormente foi realizada a conversão para linguagem GAMS (Generic Algebraic Modeling System) para utilização dos solvers na plataforma NEOS (Network Enabled Optimization System).Power distribution systems (DS) are susceptible to energy loss and voltage drops, mainly because of the way that they are operated and built. One way to minimize system loss and improve the voltage profile of DS is with the use of capacitor banks and voltage regulators (VRs) along the distribution feeders. In this scenario, the optimal placement of these devices becomes crucial. In this paper, a quadratic multi objective goal programming method is proposed to obtain the optimal placement of these devices, where the goals are energy loss (goal 1) and the total investment cost (goal 2). The model is subject to system operation constraints, such as power flow demands, limits of voltages and currents, number of stages of switched capacitors and the tap control of VRs. The increase of distributed generation penetration brings new challenges for control and operation of DS. The proposed methodology considers the effects of these power sources and their impact on optimal allocations of capacitors and VRs. With the aim of solving the optimization problem in commercial programs, a linear power flow is used. The algorithms were developed with Matlab software and the conversion was made to a General Algebraic Modeling System (GAMS) language and solved in the NEOS (Network Enabled Optimization System) platform.
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Яценко, Олексій Валерійович. "Оптимізація процесів розподілу енергії в системах з локальними джерелами генерування та акумулювання." Master's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/40797.
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Магістерська дисертація присвячена розробці алгоритму, згідно якого,з метою зниження втрат активної потужності буде здійснюватися у реальному часі реконфігурація розподільної мережі, в складі якої є джерела розподіленої генерації. Для прийняття рішень по зміні топології мережі розроблено модель адаптивного прогнозування, яка на кожному кроці прогнозування обирає модель, що показала найкращу точність на попередньому кроці і яка враховує наявної інформації відносно електричного навантаження.
Методика вибору оптимальної конфігурації мережі була розроблена на основі класичної задачі вибору місць розмикання, але окрім мети керування режимом в режимі реального часу було враховано наявність в мережі джерел розподіленої генерації. В якості моделей прогнозування було обрано методи машинного навчання (для випадку достатньої інформаційної забезпеченості) і метод нечітких часових рядів (для випадку недостатньої інформаційної забезпеченості).
В результаті досліджено було визначено, що застосування алгоритму реконфігурації позитивно впливає на зниження втрат потужності і електричної енергії в мережі і він може використовуватисяоперативним персоналоменергетичних компаній.
Очікується, що результати досліджень суттєво сприятимуть подальшому розвитку задачі управління режимами розподільних мереж в реальному часі.The master's thesis is devoted to the development of an algorithm according to which the real-time distribution network will be reconfigured, which includes distributed generation sources in order to reduce active power losses. To make decisions on changing the network topology, an adaptive forecasting model has been developed, which at each step of forecasting selects the model that showed the best accuracy and which takes into account the degree of information security according to the electrical load. The method of selecting the optimal network configuration was developed on the basis of the classical problem of selecting break points, but for the real-time control problem, the availability of distributed generation sources was taken into account. Machine learning methods (for the case of sufficient information security) and the method of fuzzy time series (for the case of insufficient information security) were chosen as forecasting models. As a result, it was investigated that the application of the reconfiguration algorithm has a positive effect on reducing power losses in the network and can be used for control personnel of substations. It is expected that the results of the research will significantly contribute to the further development of the task of managing the modes of distribution networks in real time.
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Domes, František. "Výpočet ztrát v závislosti na konfiguraci distribuční sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221206.
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This master‘s thesis deals with the calculation of losses depending on the configuration of the distribution network. The first part focuses on the general theory regarding some used calculation methods of steady operation. The next part is theoreticly dedicated to the technical losses, possibilities of their influencing and their calculation. In the practical part is carried out the choice of calculation method of steady operation. This method is implicated into the proposed program in programming environment MATLAB.Furthermore, on the basis of a partial measurement in the distribution network and using the proposed program are determined the sizes of offtakes of mesh network. For the existing mesh network is designed its radial operation. In the last part are calculated the losses of this network for both of these mentioned operations.
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Faria, Lucas Teles de [UNESP]. "Estimação espaço-temporal das perdas não técnicas no sistema de distribuição de energia elétrica." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/137834.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Neste trabalho o espaço geográfico é incorporado ao estudo das perdas não técnicas. Os trabalhos avaliados em perdas comumente não consideram a localização espacial das mesmas de forma explícita. No entanto, o estudo das características do lugar onde elas ocorrem pode trazer informações imprescindíveis para melhor compreensão do problema. O espaço é incorporado via técnicas de análise espacial de dados geográficos. A saber: análise espacial de padrões de pontos e análise espacial de dados agregados por áreas. A localização das perdas é obtida através de dados de inspeções reais georreferenciados obtidos a partir de uma concessionária de energia elétrica. Os atributos socioeconômicos do censo demográfico e da rede de distribuição de energia do lugar onde ocorrem as perdas são considerados via técnicas de regressões espaciais. São elas: modelo aditivo generalizado (GAM) e regressão geograficamente ponderada (GWR). Esses atributos são as variáveis independentes das regressões espaciais e auxiliam na explicação da disposição das perdas no espaço geográfico do município em estudo. Essas regressões são combinadas com as cadeias de Markov para produção de mapas de probabilidades de perdas. Esses mapas indicam as subáreas do município que são mais vulneráveis às perdas em termos probabilísticos. Por meio deles, estima-se a evolução das perdas não técnicas no espaço geográfico do município ao longo do tempo. Os mapas de probabilidade de perdas são uma ferramenta gráfica, de fácil interpretação e que auxiliam no planejamento de uma série de ações de prevenção e combate às perdas. Este estudo foi realizado em um município de porte médio do interior paulista com aproximadamente 81 mil unidades consumidoras, sendo que os resultados das simulações foram comparados com dados reais de inspeções em campo. A taxa de acerto para estimação das áreas vulneráveis às perdas via modelo aditivo generalizado (GAM) e cadeias e Markov foi superior a 80%.
In this work the geographic space is incorporated into the study of non-technical losses. Studies on non-technical losses do not often consider the spatial location of them explicitly. However, the study of the characteristics of the place where they occur can provide essential information to better understanding of the problem. The space is incorporated via spatial analysis techniques of geographical data; to know: spatial analysis of point patterns and spatial analysis of data aggregated by areas. The location of the losses is determined via georeferenced inspections data obtained from an electrical power utility. Socioeconomic attributes of the census and the distribution network of energy of the place where the losses occur are considered using the spatial regressions techniques; namely: generalized additive model (GAM) and geographically weighted regression (GWR). These attributes are the independent variables of spatial regressions and assist in the provision of the explanation of the losses in the geographical space of the city under study. These regressions are combined with Markov chains to produce the loss probability maps. These maps show the city subareas that are more vulnerable to losses in probabilistic terms. Through them, the evolution of non-technical losses in the geographical area of the city over the time is estimated. The loss probability maps are a graphical tool, easy to interpret and to assist in planning a series of actions to prevent and combat to losses. This study was conducted in a medium-sized city of São Paulo with about 81,000 consumer units, and the simulation results were compared with real data obtained in field inspections. The hit rate for the estimation of areas vulnerable to losses via generalized additive model (GAM) and Markov chains surpasses 80%.
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Bueno, Edilson Aparecido. "Redução de perdas tecnicas atraves de reconfigurações de redes de distribuição de energia eletrica sob demandas variaveis." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261734.
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Orientadores: Christiano Lyra Filho, Celso CavellucciDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Este trabalho apresenta uma nova visão para o problema de redução das perdas técnicas em sistemas de distribuição de energia elétrica, através de reconfiguração de redes. A principal inovação consiste em abordar o problema com a consideração explícita das variações de demandas, mas impondo-se a restrição de que as configurações devem permanecer fixas ao longo do período de planejamento. Esta característica abre a perspectiva de que a metodologia venha a ser usada na operação diária dos sistemas de distribuição. No entanto, leva a um problema de otimização bem mais complexo do que o caracterizado pela visão tradicional. Formulações para demandas fixas e variáveis são desenvolvidas. Duas metodologias distintas para abordagem do novo problema são elaboradas. A primeira utiliza a metodologia denominada Busca Menor Energia, inspirada na técnica de Abertura Seqüencial de Chaves. A segunda técnica, denominada Árvore de Aproximação, faz uso das idéias de árvore geradora de custo mínimo. Ambas são combinadas com uma busca local, denominada Troca de Ramos Generalizada, baseada na técnica de Troca de Ramos. Explora-se também uma extensão da metodologia Árvore de Aproximação caracterizada por associação com conceitos do método GRASP (Greedy Randomized Adaptive Search Procedure). Estudos de casos ilustram a aplicação das metodologias em redes de cidades brasileiras
Abstract: This work presents a new point of view for the technical losses reduction problem in electric power distribution systems, through network reconfigurations. The main innovation is the explicit consideration of demand variations and the use of a fixed configuration during the planning period. This last characteristic makes the methodology able to be used in the daily operation of distribution systems. However, it leads to an optimization problem more complex than approaches without demand variations. Formulations for fixed and variable demands are created. Two distinct methodologies for the resolution of the new problem are elaborated. The first one uses the Minimum Energy Losses methodology, inspired by the ¿Sequential Switch Opening¿ technique. The last one, called Approximation Tree, is based on algorithms for the minimum spanning tree problem. Both of them are combined with a local search procedure, called Branch Exchange by Energy, based on the ¿Branch Exchange¿ technique. An extension of the Approximation Tree methodology is proposed by using concepts of the well-known GRASP method (Greedy Randomized Adaptive Search Procedure). Case Studies demonstrate the application of the methodologies in Brazilian cities¿ networks
Mestrado
Automação
Doutor em Engenharia Elétrica
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Cambraia, Mario Sergio. "Automação da redução de perdas técnicas nos sistemas reticulados de distribuição utilizando redes neurais artificiais em redes inteligentes (smart grid)." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-05032018-102829/.
Full textAbstract:
Este trabalho apresenta a metodologia, o desenvolvimento e testes de um sistema de automação independente, baseado em Redes Neurais Artificiais, para redução de perdas técnicas em redes de distribuição subterrâneas reticuladas por meio do controle ótimo dos bancos de capacitores presentes na rede. A metodologia proposta contempla funcionalidades típicas de Redes Inteligentes, incluindo soluções práticas para o posicionamento de sensores de corrente em redes subterrâneas, coleta de medições de campo e transmissão para o Centro de Operação da Distribuição e controle em tempo real dos equipamentos de campo (bancos de capacitores). Portanto este trabalho consiste na implementação da solução através de baixo custo de investimento na mitigação do controle do fator de potência nos pontos de entrega ao consumidor, sendo que com isto ocorrem melhorias nos indicadores de qualidade e confiabilidade atendendo aos requisitos regulamentares e contratuais de fornecimento das distribuidoras. Para validação da metodologia proposta, foram utilizados os dados da concessionária de energia AES Eletropaulo sobre a Rede de Distribuição Subterrânea Reticulada do centro da cidade de São Paulo. As etapas da metodologia proposta e os principais aspectos do desenvolvimento do sistema são também descritos, bem como os testes realizados para comprovação dos resultados e validação do sistema.This work presents the methodology, development and testing of an independent automation system, based on Artificial Neural Networks, to reduce technical losses in reticulated underground distribution networks by means of the optimal control of the capacitor banks present in the network. The proposed methodology includes typical functionalities of Intelligent Networks, including practical solutions for the positioning of current sensors in underground networks, collection of field measurements and transmission to the Distribution Operation Center and real-time control of field equipment (capacitors banks). Therefore, this work consists in the implementation of the solution through a low cost of investment in the mitigation of the control of the power factor in the points of delivery to the consumer, and with this there are improvements in the indicators of quality and reliability taking into account the regulatory and contractual requirements of supply of the distributors. The energy concessionaire AES Eletropaulo had great participation in this research project, providing the necessary data of the Reticulated Underground Distribution Network of the city center of São Paulo. The steps of the proposed methodology and the main aspects of system development are also described, as well as the tests performed to prove the results and validate the system.
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Бондар, Р. В., and В. В. Ленько. "Організаційно-технічні заходи зниження витрат електроенергії в розподільних електричних мережах АТ "Чернігівобленерго"." Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/25274.
Full textAbstract:
Бондар, Р. В. Організаційно-технічні заходи зниження витрат електроенергії в розподільних електричних мережах АТ "Чернігівобленерго" : випускна кваліфікаційна робота : 141 "Електроенеретика, електротехніка та електромеханіка" / Р. В. Бондар, В. В. Ленько ; керівник роботи А. В. Красножон ; НУ "Чернігівська політехніка", кафедра електричної інженерії та інформаційно-вимірювальних технологій. – Чернігів, 2021. – 75 с.Об'єкт – електричні мережі 10/0,4 кВ АТ «Чернігівобленерго». Мета – знизити обсяг втрат електричної енергії на її розподіл в мережах АТ «Чернігівобленерго» шляхом впровадження відповідних заходів. У дипломному проекті проведено аналіз електроенергетичного балансу АТ «Чернігівобленерго», наведено проблематику рівня втрат електричної енергії на її розподіл мережами та цільову динаміку втрат відповідно до вимог чинного законодавства в сфері електроенергетики. Здійснено опис наявних засобів безоблікового споживання електричної енергії, та заходи боротьби з ними. Наведено приклади заходів по зниженню втрат електричної енергії на її розподіл мережами. Здійснено розрахунок економічного ефекту від впровадження даних заходів. Розглянуті питання охорони праці під час виконання робіт з боротьби з безобліковим споживанням електричної енергії. РОЗПОДІЛ
The object is 10/0.4 kV networks of JSC "CHERNIHIVOBLENERGO". The purpose is to reduce the amount of electricity losses for its distribution in the networks of JSC "CHERNIGIVOBLENERGO" by implementing appropriate measures. The diploma project analyzes the electricity balance of JSC "CHERNIHIVOBLENERGO", presents the issue of the level of electricity losses for its distribution through networks and the target dynamics of losses in accordance with the requirements of current legislation in the electricity sector. A description of the available means of unaccounted electricity consumption and measures to combat them. Examples of measures to reduce electricity losses for its distribution by networks are given. The calculation of the economic effect of the implementation of these measures. The issues of labor protection during the work on combating unaccounted consumption of electricity are considered.