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 - 17 de 17

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Análise da metodologia para definição dos limites de continuidade dos conjuntos elétricos das distribuidoras de energia elétrica no Brasil
(Universidade Federal do Pará, 2024-10-10) OLIVEIRA, Loreddana Monteiro Bandeira de; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
The definition of continuity indicator limits for electrical network sectors in electricity distribution companies represents the primary regulatory aspect of electricity supply quality, directly impacting consumer tariffs and investment decisions made by electric companies in electricity distribution systems. In the context of electricity sector regulation, maintaining continuity indices at appropriate levels is crucial to improving supply for consumers and ensuring tariff accessibility. This study presents the Brazilian regulation of collective continuity indicators for electricity supply, developed by the National Electric Energy Agency (ANEEL), from its implementation to the present, analyzing how each regulatory change has influenced the performance and development of the Brazilian electricity sector, with particular emphasis on the State of Pará. Pará exhibits unique continuity indicators compared to other states due to its concession area characteristics, including access challenges, long distances, and low population density. ANEEL uses benchmarking among distribution companies’ electrical sectors to establish performance targets at the end of each tariff cycle; however, the current method for setting regulatory limits does not account for factors that directly impact operational management or specific regional characteristics. This dissertation aims to analyze the current methodology for defining continuity limits for the electrical network sectors of electric companies in Brazil.
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)
Análise de estabilidade transitória em geradores distribuídos: considerações sobre a proteção 78PS.
(Universidade Federal do Pará, 2024-09-09) HERINGER, Wesley Rodrigues; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
This dissertation aims to present the transient stability analysis in Distributed Generators, considering the performance of 78PS protection, against loss of synchronization. In this context, the studies developed in this work will be considered For two distinct real cases of two cogeneration plants with synchronous generators of different powers, being a sugar-alcohol plant, which will soon be connected to An extensive rural feeder of Equatorial Energia’s Paragominas 34.5 kV substation, being in the second case analyzed a fruit pulp industry that uses biomass Resulting from the processes as fuel for the steam boiler, which connects to the a turbine, to drive a generator. In turn, this system will be interconnected in a predominantly urban feeder, in a distribution substation of 13.8 kV at Castanhal in the interior of Pará. The analyses are carried out by means of complete simulation in the time domain through software Anatem© , considering two modes of voltage control of synchronous machines: 1) without voltage control; and 2) with voltage control. The studies provide the margins of transient stability of the machines and considerations on the protection against the loss of timing of synchronous generators. The results indicate that the use of the voltage control mode of the automatic voltage regulator and the coordination between the protection of the internal feeders of the industrial consumer and the protection of the plant are fundamental to ensure the maintenance of the timing of distributed generation.
Acesso aberto (Open Access)
Avaliação de algoritmos evolucionários multiobjetivo para o problema de alocação de bancos de capacitores na presença de harmônicos
(Universidade Federal do Pará, 2017-08-10) KATAOKA, Vitor da Silva; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
The rapid growth of urban areas bring, as a consequence, an increase in the amount of loads connected to the distribution grids. Furthermore, the increase in the demand implies in equal raise in reactive loads, which are known to cause losses in the network. Thus, the utilities have a great challenge ahead, as the dynamics of the load require a greater effort in terms of expansion and improvements of the grid. In an attempt to mitigate the problems caused, the allocation of capacitor banks can become a practical, economical and technically robust solution. Nevertheless, it is extremely important to analyze the sizing and positioning of the banks, in order to achieve the best possible outcome. In parallel, the increasing use of nonlinear loads cause harmonics to appear in the system. When in conjunction with capacitor banks, it is possible to develop the far more dangerous phenomenon of resonance, where the amplitude of some of the harmonics goes beyond acceptable limits, resulting in undesirable effects. In this context, this work proposes a comparison between two multiobjective optimization tehcniques, NSGA-II and SPEA2, to solve the problem of sizing and placement of capacitor banks in electric energy distribution grids, considering the effects of harmonics produced by nonlinear loads.
Acesso aberto (Open Access)
Avaliação dos impactos da recarga de veículos elétricos na vida útil de transformadores de distribuição
(Universidade Federal do Pará, 2023-10-30) BARROS, Amanda Monteiro Pinto; AFFONSO, Carolina de Mattos; http://lattes.cnpq.br/2580696185627481
The objective of this dissertation is to provide a comparative assessment of the impacts caused by charging practices of short-range and long-range electric vehicles under different power levels on life expectancy of distribution transformers. This research is based on the use of real data of residential energy consumption collected from the region of East Midlands, United Kingdom, as well as electric vehicle charging data collected through an experimental project also conducted in the United Kingdom. This study examines transformer hottest-spot temperature and evaluates the transformer accelerated aging factor that influences the equipment's lifespan according to the thermal model presented in IEEE Standard C57.91. As a result, this study reveals that the effects caused by long-range vehicles are more pronounced, as they charge at higher power level and the charging process is longer. As the penetration level of electric vehicles increases, transformer load and hottest-spot temperature increases, especially during winter season, where residential demand escalates. In the case of vehicles with 75 kWh, penetration levels starting from 30% already causes severe violations on transformer hottest-spot temperature, contributing to a reduction in the equipment's lifespan.
Acesso aberto (Open Access)
Contribuição da geração solar fotovoltaica na certificação de edificações públicas pelo RTQ-C e em edifícios de energia zero: laboratório de ensino da Universidade Federal do Pará
(Universidade Federal do Pará, 2020) SILVA, Hosaías Alves dos Prazeres; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
This work presents the contribution of solar photovoltaic generation as a renewable source in the methodology for obtaining Level A Label in Energy Efficiency certification and for the transformation into a Zero Energy Building, being applicable to buildings and public teaching laboratories. The methodology step-by-step essentially consists of two stages: the first, through an energetic diagnosis of the building analyzed, following the guidelines established in the Technical Regulation on Quality in Commercial, Service and Public Buildings - RTQ-C (in portuguese), resulting in a proposal of energetic, financial and environmental improvement processed with the aid of the RETScreen® software; and the second, dimensioning a photovoltaic solar generation system, based on local measurement data and the Meteonorm® software, as a bonus for obtaining the Level A Label of the RTQ-C levels and with energy production capacity that makes the energetic balance of the building as positive, making it a Zero Energy Building. In order to contextualize the relevance of the work and update the reader in the state of the art applicable to the methodology, a bibliographic review is presented, directed to the benefits of Energy Efficiency in public buildings and to the RTQ-C; to the current scenario, application and contribution of Solar Photovoltaic Energy in sustainable development, in obtaining nationally and internationally recognized classifications for public buildings; and the concepts currently used by the academic community to characterize Zero Energy Buildings. The bibliographic review and methodology were applied in a case study of the Laboratory of Electrical and Computer Engineering – LEEC (in portuguese), located at the Campus Guamá of the Federal University of Pará, with presentation of the energetic, financial and environmental results, showing that it is a solution to be applied in public institutions and buildings that have available space and similar infrastructure to that of the LEEC.
Acesso aberto (Open Access)
Detecção de faltas de alta impedância em redes aéreas de distribuição: testes experimentais em laboratório e análises no domínio do tempo e da frequência
(Universidade Federal do Pará, 2023-07-04) SOUSA, Ádrea Lima de; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
The present work deals with the analysis of high impedance faults (HIFs) in overhead distribution networks. A comprehensive and in-depth study is conducted on this type of fault, as well as on some existing methods to detect HIFs. Next, the laboratory developed for experimental testing of HIFs is explained, which replicates the three-phase, three wire medium voltage distribution network with solidly grounded system at the primary substation typically used in Brazil. From the laboratory, 127 tests were performed in 18 different scenarios, including shunt faults and series shunt faults on the source side. In order to perform a comparative analysis with the existing literature on high impedance fault detection based on harmonics, the harmonic spectrum was evaluated, based on even harmonics, odd harmonics (especially the third order), and the angle of the third harmonic, obtained through the Fast Fourier Transform (FFT). The main contribution of this work lies in evaluating the peculiarities of the harmonic spectrum of voltage and current signals obtained from experimental laboratory tests for different soil topologies and tree branch configurations, and their correlation with the signal in the time domain. This provides an important foundation for the development of HIF detection algorithms. The results obtained in the analysis revealed that shunt and series shunt high impedance faults exhibit distinct behaviors in the harmonic spectrum and time domain, and a large portion of the tests performed does not fall within the thresholds established in the literature. Furthermore, it should be noted that the evaluation of the harmonic spectrum of voltage was carried out, which is usually not considered in HIF detection algorithms.
Acesso aberto (Open Access)
Diagnóstico de eficiência energética com base no INI-C e RTQ-C: estudo de caso da envoltória do Clube de Ciências da UFPA
(Universidade Federal do Pará, 2022-02-09) GOMES, Raphaele Samua Barata; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
Save energy is an emergency and it is just cut costs. Worldwide that theme has been mentioned and discussed through agreements made among countries since 1970 forward reducing the impacts of energy consume and also focused on constructions that consume about 60% of global electricity according to United Nations Environment Programme (UNEP). From here on programs and boosts came up for this sector. In 2001 in Brazil, the program called Brazilian Labeling Program (PBE) of National Institute of Metrology, Standardization and Technology (INMETRO) was created to try and to classify household appliances, electronics, vehicles and others in a group of 24 categories about their energetic efficiency. The national methodology of labeling buildings specify the technical requirements, guidelines classification of energetic sustainable construction based on a regulatory document for commercial buildings, public and services, and another for residential buildings (BRAZIL, 2010). The Technical Normative of Quality for Energetic Efficiency Level of Commercial Constructions Services and Public (RTQ-C) has standards and methods for evaluation and classification commercial, service and public constructions as well as their energetic efficiency with the objective of labeling them. The INMETRO approved on March 9th of 2021 a new Normative instruction for Energetic Efficiency of Commercial, Services and Public Constructions (INI-C) that improves the RTC-C. In this Science Club of UFPA was evaluated according to simplified method from INI-C and prescriptive method from RTQ-C of in order to compare their results and identify the differences on update regulations.
Acesso aberto (Open Access)
Iluminação pública com medição ponto a ponto e gerenciamento remoro: uma evolução tecnológica smart
(Universidade Federal do Pará, 2022-02-26) RAMOS, Ricardo Guedes Accioly; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
The concept of smart city, refers to the availability of technology for sustainable development, respect for the environment and improving the quality of life. For the implementation of a technology with such scope, you can do use of a structure existing public lighting, transforming a system used for night lighting, on a platform dynamic, providing a connection with other systems, offering services such as public safety, pollution sound, air quality, among others. This work proposes, a technology of low cost and losses, presenting as objective, the development of a prototype of a data acquisition system for point-to-point measurement, contemplating the communication with a general management system of municipal Public Lighting for the monitoring, reduction of costs with operation and maintenance, contributing to a possible discussion of the decrease in the value of the Contribution to the Cost of Public Lighting (COSIP). It is technology he can change the COSIP billing, which is calculated based on estimation of energy consumption of Public Lighting, being able to generate economy to the consumer. the search specifies the prototype capable of measuring _ parameters electric make _ communication between the measurement module and the processor and make the information available in a Wi-Fi network, capable of being acquired by a server, which processes data and sends the command back to actions. This resource is analyzed through an experiment and the _ results are treaties to conclusions finals about the topic.
Acesso aberto (Open Access)
Impacto de geradores conectados via inversores na coordenação da proteção em redes de distribuição de energia elétrica
(Universidade Federal do Pará, 2017-08-11) CORDEIRO, Murillo Augusto de Melo; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
Despite its many benefits, the Distributed Generation (DG) can adversely affect some aspects related to the operation performance of electrical power systems, especially a no so deeply explored point: the interaction between the protection systems and inverter-based power generation units. In this dissertation, the impact of inverter-based DGs units on the fuse-recloser coordination schemes used in distribution networks is thoroughly studied. The simulations were conducted using the software package DIgSILENT Power Factory through several single-phase and three-phase short circuits along the distribution network, considering different fault locations, penetration levels of DGs, operating conditions, and other aspects that impact over the protection miscoordination in an IEEE real test distribution system of 34 busbars. The contribution to the short-circuit current of inverter-based generators is also investigated through simulations on electromagnetic transients models available in the software. The simulation results shows that significant inverter-based DG penetration levels on distribution feeders increase the short-circuit current that passes through the fuse and make it operate faster than the recloser in a fault condition, leading to loss of fuse-recloser coordination in a time frame base. A general discussion of the results is performed, identifying some recommended corrective actions that should be considered in order to maintain the coordination and selectivity between the distribution system protection devices located throughout the network.
Acesso aberto (Open Access)
Impacto dos harmônicos de tensão na temperatura e desempenho de motores elétricos classes IE2, IE3 E IE4.
(Universidade Federal do Pará, 2020-02-19) MUÑOZ TABORA, Jonathan; MATOS, Edson Ortiz de; http://lattes.cnpq.br/0241051151153034; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
The introduction of new technologies as well as the improvement of materials and processes has contributed to accelerate the growth in the efficiency of the electric induction motors (IM). Currently in the market it is possible to observe the operation of IM classes IE3 and IE4, as well as minor efficiencies, in the same way proposals for IM class IE5 are being developed. This work aims to show the impact of 2nd, 3rd, 5th and 7th order voltage harmonics on the temperature and performance of IE2, IE3 and IE4 induction motor classes, the latter being a hybrid motor of permanent magnets and squirrel cage (Line Start Permanent Magnet Motor, LSPMM's). The measurements were divided into two stages, first feeding each of the motors with undistorted voltages and then entering each of the harmonics individually and in combination in percentages of 2% until reaching 25%. Considerable improvements in temperature, noise and consumption are notable in the case of the class IE4 hybrid motor, however, this motor also shows some weaknesses in its response compared to classes IE2 and IE3, mainly in the presence of harmonics. It is also presented as the presence of individual harmonics in electric motors, results in the appearance of other harmonics, according to the percentage of distortion present. Finally, in order to predict the variation of temperature in relation to the percentage of distortion, models representing this behavior were created, which represent good estimates of the temperature variation and the percentage of distortion inserted in the motor.
Acesso aberto (Open Access)
Implantação de uma middleware IoT escalável para aplicações de mobilidade elétrica multimodal.
(Universidade Federal do Pará, 2022-02-25) LOBATO, Elen Priscila de Souza; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; ROSÁRIO, Dênis Lima do; http://lattes.cnpq.br/8273198217435163
This work will present the implementation of the Dojot platform in a scalable and customized way, such as the Internet of Things (IoT) middleware of a Research and Development (R&D) Project of Multimodal Electric Mobility in the Amazon Region. Two environments were implemented with Dojot, being a development environment with Docker Compose, in only one machine, and a production environment in a Kubernetes cluster, with a master machine, two worker machines and a load balancer. To verify the consumption of CPU and memory metrics, in both environments, simulations were performed of several electric mobility devices receiving data simultaneously in Dojot. Thus, it was observed that there was a lower CPU consumption in the development environment, lower memory consumption in the production environment and the environment that best responded to the scalability issue (with the increase in the number of devices receiving data) was production. In conclusion, the implementation of Dojot in the production environment, in a Kubernetes cluster, is more advantageous in terms of scalability
Acesso aberto (Open Access)
Mitigação de variações de tensão em uma indústria cervejeira usando banco de capacitores fixos e chaveados
(Universidade Federal do Pará, 2020-06-04) SILVA JÚNIOR, Luiz Cláudio Lobo da; VIEIRA, João Paulo Abreu; : http://lattes.cnpq.br/8188999223769913
Fixed capacitor banks are equipment commonly used in industrial plants to correct power factor and/or mitigate undervoltage in their distribution networks. At heavy load levels, capacitor banks play an important role for reactive power compensation in industrial plants. On the other hand, during light load levels, the reactive power injection from capacitor banks can cause overvoltage in distribution circuits of industrial plants. The voltage variation problem in an industrial plant can adversely affect the useful life of its equipment. The combined use of fixed and switched capacitor banks is an alternative solution for mitigating steady-state voltage variation problems in industrial plants. This master dissertation proposes and investigates a technique to mitigate steady-state voltage variations in low voltage distribution circuits of a beer plant, located in the city of Benevides, PA. The proposed method is based on the reactive power compensation supplied fixed and switched capacitor banks. In recent years, the voltage quality problem has been observed in the above-mentioned beer plant, causing a drastic reduction in the useful life of its equipment. A set of real measurement data from the beer plant site was used in time-series load flow simulations, using OpenDSS software, to evaluate the proposed mitigation technique.
Acesso aberto (Open Access)
Previsão da irradiação solar utilizando método ensemble para seleção de atributos e algoritmos de aprendizado de máquina
(Universidade Federal do Pará, 2023-06-20) MEJIA, Edna Sofia Solano; AFFONSO, Carolina de Mattos; http://lattes.cnpq.br/2228901515752720
Accurate forecasting of solar irradiance is essential for effective management of power systems with significant photovoltaic generation. Machine learning algorithms, which leverage historical data and patterns to make predictions, play a crucial role in this task. One key aspect is the use of ensemble models that combine the predictions of multiple algorithms to improve forecast accuracy and reliability. In this study, ensemble models are utilized to enhance the forecasting performance by aggregating the predictions of different algorithms. Moreover, the paper proposes an ensemble feature selection method, which involves identifying the most relevant input parameters and their related past observations. This approach aims to optimize the input features used by the machine learning algorithms, ensuring that only the most pertinent information is considered for accurate solar irradiance forecasts. By leveraging the strengths of multiple algorithms and selecting the most informative features, the ensemble approach offers a robust framework for improving the accuracy of solar irradiance predictions. The performance of several machine learning algorithms, including ensemble models, is compared for solar irradiance forecasting on days with different weather patterns using endogenous and exogenous inputs. The algorithms considered are AdaBoost, SVR, RF, XGBT, CatBoost, VOA, and VOWA. The proposed ensemble feature selection relies on the RF, IM, and Relief algorithms. The forecast accuracy is evaluated based on several metrics using a real database of the city of Salvador, Brazil. Different weather forecasts are considered: 1 hour, 2 hours, 3 hours, 6 hours, 9 hours, and 12 hours in advance. Numerical results show that the proposed ensemble feature selection improves forecast accuracy, and that the VOWA model selected with the best-performing algorithms presents forecasts with higher accuracy than the other algorithms at different forecast time horizons. This research demonstrates the effectiveness of ensemble models and feature selection techniques in enhancing solar irradiance forecasting, providing valuable insights for efficient power system management.
Acesso aberto (Open Access)
Proteção de sistemas de carregamento de veículos elétricos contra descargas atmosféricas
(Universidade Federal do Pará, 2022-06-13) NARDI, Igor Rodrigues de; LEAL, Adônis Ferreira Raiol; http://lattes.cnpq.br/4099411616990036
As electric vehicles and renewable energy expand, there is also a need to investigate new methods of lightning protection for these new technologies. This work aims to evaluate the performance of electric vehicle charging systems against lightning during their transitory regime. Models of two charging stations, one connected to the AC power network and the other disconnected, were used for the analysys. Additionally, a voltage surge model caused by lightning were used. The results of this paper showed the changes in the voltage waveforms at the input and output of the circuits, making it possible to assess which points are more vulnerable, requiring a better protection. In addition, this work evaluates if two electric vehicle charging stations of the Center of Excellence in Energy Efficiency of the Amazon – CEAMAZON – are adequately protected against atmospheric discharges. For this, it was based on studies carried out in Asia, Europe and the Brazilian standard. It was found that, despite the CEAMAZON building having an adequate LPS, the electric vehicle charging stations may be susceptible to damage, mainly due to the indirect effects caused by lightning strikes in the vicinity of them.
Acesso aberto (Open Access)
Qualidade da energia elétrica de uma nanorrede de distribuição em corrente contínua sob diferentes condições operacionais
(Universidade Federal do Pará, 2023-02-13) FONSECA, Arthur Corrêa da; GALHARDO, Marcos André Barros; http://lattes.cnpq.br/6672470707462259
This work presents an experimental study of electric power quality in a Direct Current Distribution Nanogrid (DCDN) implemented in the testing area of the Grupo de Estudos e Desenvolvimento de Alternativas Energéticas (GEDAE) building at the Universidade Federal do Pará (UFPA), Guamá campus, city of Belém-Pará. Power quality events are identified through tests carried out on the DCDN and classified based on the recommendation of the Institute of Electrical and Electronic Engineers (IEEE) - Recommendation Practice for Monitoring Electric Power Quality - Std 1159, 2019. The characteristics of the DCDN and the load banks subjected to the tests are presented, using commercial loads available on the market, as well as the instrumentation used for electrical and environmental measurements and data acquisition. Among the identified power quality events, long-term variations, transient events during the start operation of DC-DC converters, voltage elevations and sags with the operation and output of loads, and voltage ripple along the DCDN are evaluated. As an additional case study, interruption events are also evaluated in a DCDN located in Onças Island, in the municipality of Barcarena. Thus, in view of the tests and measurements carried out, power quality events present in the DCDN supplied by dispersed photovoltaic generators and battery banks are evidenced, highlighting the influence of these events on different loads connected along the distribution network and under different operational condition
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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