Dissertações em Engenharia Elétrica (Mestrado) - PPGEE/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2316

O Mestrado Acadêmico inicou-se em 1986 e pertence ao Programa de Pós-Graduação em Engenharia Elétrica (PPGEE) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).

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Agora exibindo 1 - 15 de 15

Acesso aberto (Open Access)
Análise de Desempenho de Meta-heurísticas Aplicadas ao Problema de Restauração de Redes de Distribuição.
(Universidade Federal do Pará, 2020-02-20) BATISTA, Vítor dos Santos; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
In the last years, several meta-heuristics have been used to solve the problem of restoring distribution systems efficiently. Among them, the Multiobjective Evolutionary Algorithm with Node-depth encoding (MEAN) stands out, which together with Node-Depth Encoding (NDE) makes a great advance in the field. All this because the NDE makes changes on the topology of the distribution system without losing radiality and reestablishing the power supply for all disconnected loads after the fault. Due to the lack of exploration of other meta-heuristics that use NDE as a data structure, this work aims to evaluate a performance analysis comparing MEAN with three other meta-heuristics, Tabu Search, Artificial Bee Colony and Evolutionary Strategies. The analysis was performed in three distribution systems the84-bus, 119-bus and 135-bus.s
Acesso aberto (Open Access)
Cálculo de perdas técnicas e não técnicas nas redes de distribuição de energia elétrica usando a definição de impedância equivalente de perdas
(Universidade Federal do Pará, 2018-10-17) PAYE, Juan Carlos Huaquisaca; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
This work presents a new concept called Loss Equivalent Impedance (LEI), which is characterized by being a practical and economical method that allows calculating technical and non-technical losses in electricity distribution networks with good accuracy, for which it uses the data that any electric utility has, such as the user's electricity bills, the grid's electrical parameters and the measurements of power and currents at the substation coupling point. To show the application of this method, this document covers the data processing and description of the software used to simulate the operation in the test systems IEEE 13 and 37 buses networks, considering that they present technical and non-technical losses. In addition, these systems are evaluated with different operational conditions, including the incorporation of a photovoltaic plant. The cases evaluated in this work show that the method can be used to plan and monitor the electricity distribution networks, considering the separation of technical and non-technical losses, so that in future reduction actions concerning these losses can be managed, since of unmanaged electricity losses is translated into considerable economic losses for both the utility and customers and indirectly for the country. The results presented in this dissertation, regarding the application of the Equivalent Operational Impedance to the calculation of technical and non-technical losses, have demonstrated the effectiveness of the proposed methodology, so that it is foreseen a great potential for the application of the proposed procedure in the electrical sector mainly in the distribution utilities.
Acesso aberto (Open Access)
Desenvolvimento de um simulador de redes elétricas para estudos da propagação de harmônicos
(Universidade Federal do Pará, 2016-08-23) LIMA, Diorge de Souza; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
The electricity sector in Brazil has faced many changes due to the modernization of electrical equipment, especially when it refers to residential consumers. This has provided a considerable increase in the level of harmonic distortion in the electric distribution networks, which can be explained by the large use of devices based on power electronics in an attempt to make them more efficient and compact. Therefore, it becomes necessary execute analysis of the levels of harmonic distortion in the power systems. Monitoring by power quality analyzer is the best way to collect data of the electrical system; however, the computer simulation is an efficient tool capable of reproducing the disturbances and behavior of the electric networks for different operating modes. Thus, this paper aims to present a computational environment that helps the harmonic propagation studies in electrical systems. For this, it was used the software ATP (Alternative Transient Program) for modeling the electrical system, the harmonic behavior of a nonlinear load is represented by effective values of harmonic currents in function of time. The measurements were obtained through power quality analysis of a distribution network in the North Region of Brazil. Thus, for this set of measures, a set of simulations was performed, providing for the users the values of harmonic voltages for all buses of the electrical system. Therefore, with the simulator of electrical networks it is possible perform harmonic propagation studies in several electrical systems, and it can work as a strategic planning tool for the use of mitigating measures or for the strategic control of harmonic distortion, from evaluations of most critical moments of harmonic distortion at all points of the network. To demonstrate its use, the industrial system of 13 bar was used as a test system for analysis in this dissertation.
Acesso aberto (Open Access)
Gestão de armazenamento de energia integrado com fontes renováveis e intermitentes
(Universidade Federal do Pará, 2023-07-13) MORAES, Wuanda Letícia da; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
This work address the configuration of energy storage integrated to intermittent renewable sources, especially photovoltaic systems, connected to the electricity distribution network. This is the result of the Research and Development Project, “Multimodal Electric Mobility Intelligent System (R&D) Applied in the Amazon Region (SIMA)”, developed at the Amazon Energy Efficiency Center (CEAMAZON), where there is a mini electric network with photovoltaic generation, diesel generation, electric vehicles charging stations, energy storage and coupling point with the CA network of the university city Prof. Dr. José da Silveira Netto, of Federal University of Pará. The mini electric network management is accomplished by a hybrid inverter associated with a load controller, capable of informing and managing the power that is being generated by the FV arrangements, the charging state of the battery bank, which also has its own management, through the BMS (Battery Management System); and the power being injected into the AC bus. With the case study, management strategies were defined through demand-side energy management, time shift, with a 55% reduction in the total cost of the 2022 annual bill for the CEAMAZON building. In addition, an economic feasibility analysis was presented through the tip load factor (FCp) with PDE 2032 VLP , arriving at a positive and justifiable result for application. Finally, a carbon exchange analysis arrived at a sustainability equivalent of 11 trees typical of the Amazon rainforest cultivated for the total emissions avoided in 2022 in the university city; and a carbon credit 298.43 tCO2, corresponding to R$ 131,902.4 for the carbon market.
Acesso aberto (Open Access)
Manutenção preditiva em sistemas elétricos de potência utilizando registros de dispositivos eletrônicos inteligentes (IEDS)
(Universidade Federal do Pará, 2019-11-08) SILVA, Vanderson Geraldo Aranha da; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
Today, electricity generation and transmission utilities are paid for the availability of their transmission functions (FTs) and no longer for what is generated and transmitted in the National Interconnected System (SIN). In this context, more and more efforts are made by the electric energy generation and transmission transmitting utilities so that untimely disconnections do not occur or be avoided. In addition to the loss of revenue when unplanned outages occur in the system, regulators agents, such as the National System Operator and the National Electric Energy Agency, subject utilities to a rigid oversight process. Investments in technology are allowing new directions for the operation and maintenance of power equipment, since high-capacity data-processing devices are enabling optimized predictive maintenance techniques based on the protection, control and monitoring of electrical quantities of the electrical system, as well as guaranteeing the speed and security of information. Intelligent Electronic Devices (IEDs) are multiprocessor systems with hardware and software that continuously work with electrical quantity measurements, protection, command, control, monitoring and have robust memories to record lists of events and waveforms of the analog signals in real time. In this work, real cases will be presented in which FTs shutdowns were avoided with the analysis of the lists of events and waveforms of the IEDs that form the Eletronorte (Pará) substation protection system. This data analysis technique allows the company to perform predictive maintenance of their power equipment in anticipation of the problem, to have useful information to better decision making, as well as to become possible to significantly reduce their financial losses in the operation and maintenance of its electrical system.
Acesso aberto (Open Access)
Mapeamento de oportunidades de negócios a partir de laboratórios de pesquisa e desenvolvimento: estudo de caso CEAMAZON
(Universidade Federal do Pará, 2014-11-28) PEREIRA, Márcio Roberto do Carmo; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
This is work focuses on innovation and technology as a differentiating factor and generation of Business Technology Based Projects from the Research and Development Center of Excellence in Energy Efficiency in the Amazon - CEAMAZON, to identify and rank potential projects arising from Projects R&D Labs in this energy center. It is used the methodology of radar of technology and business innovation (Ranti) togather and to generate a portfolio of businesses in energy, and the potential for Innovation of CEAMAZON for society to make use of the knowledge generated from this research center, the creation of companies and businesses by entrepreneurs, investors and / or entrepreneurs in order to create jobs, more technology and multiply the capacity of CEAMAZON to create more projects with R&D interface with the market.
Acesso aberto (Open Access)
Metodologia para cálculo de perdas técnicas e não técnicas de alimentadores de distribuição via estudos de fluxo de carga pelo Método Somatório de Potência Modificado
(Universidade Federal do Pará, 2017-04-04) OLIVEIRA, Rafael Cavalcante de; NUNES, Marcus Vinicius Alves; http://lattes.cnpq.br/9533143193581447; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
Fundamental to economic activity the electric energy sector in Brazil is regulated by the relevant agency, ANEEL. Which regulates and supervises the production, transmission / distribution and commercialization of electric energy in accordance with the policies of the federal government. Among other functions, ANEEL defines the tariff values to be charged by the concessionaires through tools such as Tariff Reviews. The non-technical losses (or commercial losses) of the electric power company are part of the energy tariff composition, being passed on to the final consumer, within a pre-established limit. Therefore reducing commercial losses is a fundamental issue for energy distributors, as it increases the profitability of the company and decreases energy costs to the end user. This work, being the result of a research project carried out in partnership between the power distribution utility of the state of Pará, CELPA, and the Federal University of Pará, UFPA, aims to develop a new methodology in the scope of operational planning, including technical loss information and techniques in load flow studies using modified Power Summation Method. Initially, an analysis of the scenario of the Brazilian electric sector is presented, with emphasis on the frauds and thefts of energy, considering the impacts of this reality from the financial point of view for both the energy concessionaires and the clients, as well as the impacts on the services to these consumers. Afterwards a new methodology, able to more assertively determine the actual operating state of the distribution network is showed, taking into account the commercial losses of energy, together with real measurements of active and reactive power injected in the feeders, in the point of common coupling with the substation. The method developed using both an IEEE 13-bus test feeder and an urban feeder of the Belém metropolitan network belonging to the Pará power utility CELPA, is applied and the results obtained are then presented and analyzed.
Acesso aberto (Open Access)
Mineração de dados baseada em inteligência computacional: uma aplicação à determinação da tipologia de curvas de cargas
(Universidade Federal do Pará, 2011-09-13) ALVES, Elton Rafael; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
The energy utilities, for ensure that your network be reliable, need to perform a procedure for study and analysis based in your functions of delivery of energy in the points of the consumption. This study, generally called of systems planning of electric power distribution, is essential for ensure that variations in the energy demand doesn’t affect the system performance, that should whether keep operating of technique manner and viable economically. In these studies are generally analyzed, demand, typology of load curves, load factor and other aspects of the existing loads. Considering then the importance of the determining of the typologies of load curves for utilities in their planning process, the Electricity Company of Amapá (CEA) conducted a campaign of measures of load curves of the distribution transformers that were utilized for obtainment of the typologies of load curves that characterize your consumers. In this paper presents the satisfactory results obtained as from the utilization of Data Mining based in Computational Intelligence (Self-Organizing Maps of Kohonen) for selection of the typical curves and determination of the typologies of load curves of residential and industrial consumers for the city of Macapá, located in the state of Amapá. The self-organizing map of Kohonen is a type of artificial neural network that combines operations of projection and clustering, allowing the realization of exploratory data analysis, with the goal of producing summarized descriptions of large data sets.
Acesso aberto (Open Access)
Otimização do processo de montagem de componentes eletrônicos de superfície utilizando ferramenta multicritério
(Universidade Federal do Pará, 2015-10-30) CASTRO, Anderson de Oliveira; LEITE, Jandecy Cabral; http://lattes.cnpq.br/8299626651681733; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
The optimization problems of industrial process attracted many researches since the early 90's of the last century. The production volume increase, market competition increase and technological advances pushed the industries to seek for low cost and quick implementation solutions. One of the processes that became the core reason for increasing the sales volumes was the surface mount technology composed by printing, automated chip mounting and reflow oven which replaced the through hole technology. This research formulated a new point of view for optimization of modular chip mounters based on the already known feeder assignment problem and assembly head motion problem applying the global optimization using the non sorting dominance genetic algorithm the NSGAII in regard of the total cycle time reduction. The modeling of the fitness functions was presented and the multi criteria optimization tool was described using the machine functions and constraints. The same method could be applied to describe other type of machines to support future research.
Acesso aberto (Open Access)
Otimização multicritério para despacho econômico e ambiental de usinas térmicas utilizando enxame de partículas
(Universidade Federal do Pará, 2015-03-27) AZEVEDO, Raimundo Edney dos Santos; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
One of the main objectives in the generation of electricity in thermal systems is to minimize fuel consumption through optimal allocation of power generation for each generating unit via the economic dispatch, maintaining pollutant emissions within the limits of environmental licensing, whose integrated solution is subject to a set of equality and inequality constraints. Due to environmental concerns that were developed from the emissions produced by power plants that use fossil fuels, the economic dispatch that minimizes only the total fuel cost can no longer be considered a suitable option of dispatch. This paper therefore proposes a strategy based on mathematical models to solve the problem of load dispatch considering the economic problems and the emission of pollutants, whose premises are combined into an objective function and several electrical and emission constraints using the LabView software environment. The results achieved with the application of the procedures proposed here to a thermal power plant in the city of Manaus AM, appear quite positive towards providing dispatch solutions that proved sustainable with regard to the economic and environmental aspects considered.
Acesso aberto (Open Access)
Sistema de apoio à tomada de decisão para atribuição de responsabilidade por perda de qualidade devido à variação de tensão de curta duração
(Universidade Federal do Pará, 2009-03-13) FONSECA, Maria da Conceição Pereira; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
The electromagnetic environment surrounding the planet Earth has a fundamental role in the preservation and development of the living creature, and perhaps the last frontier of human knowledge to be dominated completely, before we ventured to the space outside in search of new opportunity outside. This environment is only now being tamed and best known, and this endeavor has as lynch pin the use of appropriate sensors that can detect and quantify these electrical effects, to serve as a basis for the generation of theories, to explain the underlying phenomena, including in this, the sensors of atmospheric electricity. This work intends to make a comprehensive analysis of these sensor’s systems of atmospheric electricity in use today, evaluating their models of operation, its limitations and its intelligence, and producing a summarized basic specifications for development of better sensors and setting standards for metric types of the variables to be measured, to cope with the currents and future demands in this field of knowledge. Additionally, the processes involved in the calibration of these sensors will be addressed with a review of computational model based on the method of moments (MoM) and other that my be used for evaluation of electromagnetic fields emitted by remote charges patterns and electrical currents, which serve to support and basis for these calibrations.
Acesso aberto (Open Access)
Sistema de aquisição de dados para monitoramento de malha de terra energizada
(Universidade Federal do Pará, 2015-11-18) SOUSA, Kleiber Tenório de; TOSTES, Maria Emilia de Lima; http://lattes.cnpq.br/4197618044519148; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
The good performance of grounding system in substations and generating plants is an essential condition for their operation according with established quality standards. Therefore a continuous monitoring system for grounding grid is an important tool to aid technical teams to identify failed zones that depreciate the Power Systems operation. Some traditional measuring methods in grounding grids need the power system shutdown. However the concession contracts allow penalties for the unavailability of generation and transmission facilities. Therefore the constant adoption of grounding grid evaluation without the plant shutdown is important. Having these specifications as target this Dissertation presents an embedded system development for voltage and current measurement. Another proposed system component is the software to manage the measuring network and organize the collected information in a database to produce grounding system operation reports. An important aspect of the system is the adoption of wireless network technology to data transfer between each measuring instrument and a web server installed in the power plant operation center. The experimentally obtained results reinforce the system contribution and encourage new developments.
Acesso aberto (Open Access)
Uso de árvore de decisão para avaliação da segurança estática em tempo real de sistemas elétricos de potência
(Universidade Federal do Pará, 2014-09-12) RODRIGUES, Benedito das Graças Duarte; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
The techniques used to Static Security Assessment in power systems depend on the implementation of a large number of cases of load flow for various topologies and system operating conditions. In real-time operation environments, this practice is difficult to implement, especially in large systems where the execution of all cases of load flow needed, requires high time and computational effort even for the current resources available. Data Mining techniques such as decision tree have been used in recent years and have achieved good results in the applications of static and dynamic security assessment of electrical power systems. This work presents a methodology for static security assessment in real-time of electrical power systems using the decision tree, where off-line load flow simulations, performed by software ANAREDE (CEPEL), has been generated an extensive labeled database related to the state of the system for various operating conditions. This database was used for induction of decision trees, providing a model for fast and accurate prediction that classifies the state of the system (secure or insecure) for real time application. This methodology reduces the use of computers in the on-line environment, since the processing of the decision tree requires only checking some if-then logical instructions of a limited number of numerical tests in the binary nodes for the attribute value definition that satisfies the rules, because these tests are performed in a same number of hierarchical levels of the decision tree, which is usually reduced. With this simple computational processing, the task of the static security evaluating will be able to be performed in a fraction of the time required to perform by faster traditional methods. To validate the methodology, a case study based on a real power system was performed, where for every contingency classified as insecure a corrective control action was executed from the decision tree information on the critical attribute that affects the security. The results showed the methodology is an important tool for static security assessment in real time for use in a center's operation system.
Acesso aberto (Open Access)
Uso de técnicas de mineração de dados para a extração de indicação de falha na operação de hidrogeradores a partir de medidas de descargas parciais
(Universidade Federal do Pará, 2016-06-17) PARDAUIL, Ana Carolina Neves; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
By studies conducted by CIGRE in 2009, it was found that the main source of hydro generator failures is correlated to the machine electrical insulation. Due to this fact, monitoring the stator winding conditions became an important supervising procedure. A very used practice to accomplish this supervision is through the measurement and analysis of partial discharges (PDs), being this practice one of the most effective and secure methods for analysis of generator stator insulation. However, although PDs have well-defined standards, it is not trivial to classify the obtained PDs signals in these patterns, mainly due to the large number and variety of PDs occurrences. Today, the significant increase in the amount of PDs data available was due to improvements in equipment and software for PDs monitoring, as for example the system IMA-DP, which has contributed to better planned and more frequent measurement campaigns. So, this work proposes the use of an intelligent tool to facilitate the process of identification and diagnosis of partial discharges, based on data mining techniques using decision trees (DT), which is a solution for analyzing large amount of data. In the specific case presented in this dissertation it was used 2,435 measurements obtained for phase A of a hydro generator of the Tucurui Hydro Plant, which was essential to validate the proposed method, because they represent real data obtained from the Hydro Plant operation. A hybrid approach (supervised/unsupervised) was used to identify and rank PDs patterns among the well-known forms of DPs. A fast and very satisfactory PDs classification procedure was achieved, especially when converting data from statistical maps into amplitude histograms, thus, obtaining well-defined clusters and a created decision tree that achieved global indices of accuracy above 98%.
Acesso aberto (Open Access)
Utilização de métodos ativos na transformação de um prédio em um edifício de energia zero: estudo de caso da biblioteca central da Universidade Federal do Pará
(Universidade Federal do Pará, 2020-05-06) ALBUQUERQUE, Bruno Santana de; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
This dissertation proposes an energetic evaluation of a University Building transformation into a Zero Energy Building (ZEB), by using active methods such as Lighting System (LS), Photovoltaic System (PV) and Storage System (SS), and presents its application in the form of a case study. The purpose of this study is to analyze the energy balance between the UFPA Central Library, the implementation of the LS, the PV, the distribution system and the SS, aiming at the load autonomy. Satisfactory results were obtained for different scenarios created by the load variability, according to the university calendar, and the photovoltaic generation intermittency. The proposed LS reduced the building consumption by 44%. Using the PV system generates enough energy to supply most of the building load, however only 53% of this energy benefits the building, the energy surplus supplies other university loads. However, the SS integration allows the building to benefit 77% of the generated energy. Therefore, the proposed systems provide the ZEB concept to the study case building.

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