Engenharia Elétrica

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http://repositorio.ufes.br/handle/10/17617

Programa de Pós-Graduação em Engenharia Elétrica

Centro: CT
Telefone: (27) 4009 2663
URL do programa: https://engenhariaeletrica.ufes.br/pt-br/pos-graduacao/PPGEE

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Agora exibindo 1 - 8 de 8

Controle parcial de potência em sistemas de energia através de um transformador de estado sólido híbrido
(Universidade Federal do Espírito Santo, 2024-06-10) Del Piero, Fádua Cozac Gonçalves; Co-orientador1; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador3; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador4; ID do co-orientador4; Lattes do co-orientador4; Orientador1; https://orcid.org/; http://lattes.cnpq.br/; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; 1º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 2º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 3º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 4º membro da banca; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
In recent years, there has been an increasing focus in science on engineering to optimize components and systems, driving advances in semiconductor technology in power electronics. This has enabled the use of higher switching frequencies, reduced volume, and increased efficiency. Within this context, microgrids, which rely on transformers and converters to integrate sources, loads, and systems, are gaining prominence. With the growing adoption of distributed energy sources, especially renewables, the use of efficient converters to control voltage, current, and power flow becomes crucial. However, the limitations of conventional transformers, such as limited voltage control and large volume, restrict system optimization. An alternative is the Solid-State Transformer, which offers advantages such as reactive power compensation, voltage regulation, and reduced size. Despite these benefits, the implementation of the Hybrid Solid State Transformer faces challenges, such as higher cost and lower efficiency. To overcome these difficulties, a hybrid topology is proposed that combines the conventional transformer with the Solid-State Transformer. In this work, a hybrid system was developed that uses the Solid-State Transformer for partial energy control, while the conventional transformer performs most of the transformation. Additional functionalities such as parallel and series active filters, reactive compensator, and dynamic voltage regulator were implemented. The system was analyzed under various load and supply profiles to validate the proposed topology and control, thereby demonstrating the feasibility of the configuration for a real-world situation
Detecção de eventos de obstrução em válvula no processo de lingotamento contínuo com uso de aprendizado de máquinas
(Universidade Federal do Espírito Santo, 2024-05-25) Diniz, Ana Paula Miranda; Co-orientador1; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador3; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador4; ID do co-orientador4; Lattes do co-orientador4; Orientador1; https://orcid.org/; http://lattes.cnpq.br/; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; 1º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 2º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 3º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 4º membro da banca; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
The continuous casting process, used in the manufacture of steel plates, is currently the most economical and efficient way of production within the industry. Although continuous casting is a widely used process, some problems associated with the process have not yet been resolved, one of them being the obstruction of the Submerged Entry Nozzle (SEN), which controls the flow of steel between the tundish and the mold. This obstruction, also called clogging, not only impairs the quality of the product but also results in lower process yield, resulting in losses. Thus, clogging detection is of fundamental importance, because control actions can allow the system to operate for a longer time. In this work, methodologies based on Machine Learning and Deep Learning are presented and compared to detect the occurrences of clogging from historical data of process variables. In general, the performance of the classifiers achieved very promising results in real data with unbalanced classes. In particular, the method employing spatiotemporal analysis, using four process variables, obtained a remarkably superior performance when compared to the others, reaching averages of Precision and Recall, respectively, of 95.53% and 97.33%. To reduce the false positive and negative rates, a post-processing heuristic was implemented and applied to the model output, achieving a Precision and a Recall, respectively, of approximately 98% and 99%. To the best of our knowledge, these results have never been found in the literature. Although a detailed comparison is unfeasible due to the differences between the datasets and their inaccessibility, the modeling proposed here reached higher performance levels when compared to the results found in the literature to solve this industry’s problem. The high and unprecedented results obtained in this work, therefore, will contribute both to the improvement of the quality of the final product and to the reduction of costs associated with steel production, since the more effective classification of clogging occurrences can help operators in the corrective action planning
Development of multifunctional structures for measuring temperature, strain, angle, and vibration frequencies using additive manufacturing techniques
(Universidade Federal do Espírito Santo, 2024-04-17) Pires Junior, Robertson Wesley Monteiro; Frizera Neto, Anselmo ; https://orcid.org/0000-0002-0687-3967; http://lattes.cnpq.br/8928890008799265; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador3; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador4; ID do co-orientador4; Lattes do co-orientador4; Leal Junior, Arnaldo Gomes ; https://orcid.org/0000-0002-9075-0619; http://lattes.cnpq.br/7246557168481527; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/0000-0002-4670-9651; http://lattes.cnpq.br/4171039583783036; Rodríguez Díaz, Camilo Arturo ; https://orcid.org/0000-0001-9657-5076; http://lattes.cnpq.br/2410092083336272; Marques, Carlos Alberto Ferreira; https://orcid.org/; http://lattes.cnpq.br/; 3º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 4º membro da banca; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
This Master Dissertation presented the development of different multifunctional structures embedded with fiber Bragg gratings (FBGs). Additive manufacturing techniques were used to manufacture these structures. The manufactured multifunctional structures consist of an artificial tendon capable of monitoring deformation parameters, temperature, and curvature angle; a temperature sensor capable of measuring it in different environments; and a frequency meter in the form of a cantilever beam. The artificial tendon was manufactured by pouring polyurethane resin (PU) into a mold made with polylactic acid (PLA) filament so that the resin coated the FBGs. The temperature sensor was manufactured with light-cured resin and the FBG was embedded in an aperture in the structure. Two accelerometers were manufactured by FFF using filaments of nylon and 17-4 PH, which is stainless steel but in the form of a filament aggregated with polymeric particles. The materials used to manufacture the structures were characterized by static and dynamic mechanical tests. In static tests, it was noted that Young’s modulus (E) increases as a function of the increase in the cross-section of the specimen, which was modified by varying the infill and wall thickness of the body. However, the mechanical resistance of the optical fiber predominated over these constructive characteristics after embedding in the test specimens. This impact is more noticeable in the results of the fiber embedded in PU since the test specimen’s E with the fiber embedded is almost 10 times greater than that with raw PU. In dynamic tests, the amorphous polymer chains of nylon embedded with fiber cause the material to present different E during its transition to the rubbery plateau, which is only reached from 60 ℃, while 17-4 PH shows no difference notable in E when the vibration frequency varies. The artificial tendon was characterized for strain showing different sensitivities between the FBGs positioned in the center and close to the tendon wall. Furthermore, the tendon presented an average sensitivity of 9.06 pm/℃ for characterization between 0 ℃ and 30 ℃ and a root mean square error of 3.25 ° when the curvature angle varied from 0° to 90°. The 17-4 PH accelerometer cantilever showed sensitivity of 1.79 pm/V in the range from 0.5 V to 2.0 V when the shaker was set to 10 Hz and 3.61 pm/V for 100 Hz. Therefore, in future works, the intention is to apply the multifunctional structures developed, with the artificial tendon being used in the actuation of robotic parts, and the accelerometers in predictive vibration analysis, for example
Estudo da viabilidade técnico-econômica preliminar de um sistema térmico híbrido PTC-RSU para a geração de energia elétrica no Estado do Espírito Santo
(Universidade Federal do Espírito Santo, 2024-06-27) Sant’Ana, Brunella Bermudes Prati; Santos, José Joaquim Conceição Soares ; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador3; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador4; ID do co-orientador4; Lattes do co-orientador4; Fardin, Jussara Farias ; https://orcid.org/; http://lattes.cnpq.br/; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; Rocha, Helder Roberto de Oliveira; https://orcid.org/; http://lattes.cnpq.br/; Faria, Pedro Rosseto de; https://orcid.org/; http://lattes.cnpq.br/; 3º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 4º membro da banca; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
The growing concern about rising global temperatures has sparked debate in various sectors of society. In the context of electricity generation, the transition to more sustaina ble energy sources is becoming an urgent necessity, given the importance of electricity in all spheres of modern life. This study aims to analyze the technical and economic feasibi lity of implementing a thermosolar-biomass plant in the state of Espírito Santo, with the aim of providing a clean and sustainable source of energy for both the state and the regio nal distribution network. The proposed system consists of a combination of technologies, including a solar generation plant with parabolic trough collectors (PTC) together with the combustion of locally generated Municipal Solid Waste (MSW) in order to mitigate the intermittency of the solar source. The methodological approach of the research pre sented involves localization studies using road routes for transporting the MSW, research into solar irradiation in the location of the plant, simulations using IPSEPro software to thermodynamically analyze the plant and determine electricity generation, as well as preliminary economic feasibility studies, considering basic investment costs and return. The results of the research indicate that it is possible to achieve a generation capacity of between 28MW and 78MW of gross electrical power, depending on the configuration of the hybrid plant. For maximum electricity generation, the plant’s solar field is made up of 88 collectors, each 1.50 meters long, installed over an area of approximately 7.2 hectares. To guarantee continuous energy generation, it was estimated that a logistical quantity of 27.04kg/s of MSW could be delivered to the site identified in the studies as ideal for installing the plant, located in Cariacica, where the waste is incinerated and the heat from combustion is used to heat the solar field fluid at night. Economically, the project has a maximum initial investment of around R$522,000,000.00, with a return of up to 7 years (considering attenuation scenario of 60% of revenue), which demonstrates the viability of the project. However, an initial investment of this size is only feasible with the support of public policies to encourage the use of renewable sources and low interest rates for financing. The investment and development of this hybrid power plant initiative represents a significant step forward in the state’s renewable energy sector, contributing to the reduction of greenhouse gas emissions and the diversification of the regional electricity matrix
Methodologies to improve one-class classifier performance applied to multivariate time series
(Universidade Federal do Espírito Santo, 2024-04-05) Machado, André Paulo Ferreira; Ciarelli, Patrick Marques ; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador3; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador4; ID do co-orientador4; Lattes do co-orientador4; Munaro, Celso José ; https://orcid.org/; http://lattes.cnpq.br/; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; Vargas, Ricardo Emanuel Vaz ; https://orcid.org/; http://lattes.cnpq.br/; Serra, Ginalber Luiz de Oliveira ; https://orcid.org/; http://lattes.cnpq.br/; Coelho, Leandro dos Santos ; https://orcid.org/; http://lattes.cnpq.br/; Lima Netto, Sergio ; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
This work proposes novel methodologies to improve the performance of one-class classifiers applied to multivariate time series data. The main method is through clustering of multivariate time series. Datasets arising from real processes come from the available sensors and are affected by many factors, such as aging of the process, changes in the operation region, and equipment malfunction. Despite that, one expects that the classes represented by such diverse data can be unveiled via trained classifiers. This work hypothesizes that the overall performance can be improved by training sets of one-class classifiers with subsets of data clustered by similarity, obtained by DTW Barycenter Averaging (DBA) which is used to measure the similarity between the time series and each cluster. The proposed method is applied to one class classifiers since they are trained only with the target class, which is clustered based on time series similarity using Dynamic Time Warping and k-means. Additionally, a second approach is proposed, called time-shift of labels, to improve the differentiation between normal and faulty data. This method is applied during the training phase and focuses on particular situations involving the transition from normality to faulty data, where the boundaries are difficult to differentiate (overlapping data). The time-shift results show a mitigation of the effect of overlapping data. The advantages of the techniques are illustrated through their application to two public datasets one from the oil industry with instances characterizing eight classes of data represented by five time series (3W dataset), and another from a hydraulic system for the study of typical hydraulic system failures with five classes and seventeen time series (Condition monitoring of hydraulic systems - ICM dataset). For the 3W dataset, seven classes are selected to train Long Short Term Memory (LSTM) classifiers using the variables and instances clustered using time series clustering algorithms. The results demonstrate that increasing the similarity of training data tends to improve the performance of the LSTM classifier, achieving an increase of 10% in the overall performance on the 3W dataset. In a specific case, where the clustering model raised the similarity by 84%, the classification performance improved by 21%. For condition monitoring of hydraulic system data, the proposed method achieved a significant performance improvement of over 40% compared to the baseline model. Notably, in the specific case of leakage fault, the classification performance improvement rises by 64%
Performance evaluation of a 5G-based hybrid visible light and radio frequency communication system
(Universidade Federal do Espírito Santo, 2024-04-15) Peterle, Augusto Cesar Federici; Rocha, Helder Roberto de Oliveira ; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador3; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador4; ID do co-orientador4; Lattes do co-orientador4; Silva, Jair Adriano Lima ; https://orcid.org/; http://lattes.cnpq.br/; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; Segatto, Marcelo Eduardo Vieira; https://orcid.org/; http://lattes.cnpq.br/; Pohl, Alexandre de Almeida Prado; https://orcid.org/; http://lattes.cnpq.br/; 3º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 4º membro da banca; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
The development of 5G is an ongoing process and annually release are published by 3GPP considering fundamental aspects such as network’s physical layer, numerology, bandwidth, modulation, among others. For new releases, a rapid prototyping is valuable for experimental demonstrations and proof-of-concepts. The usage of the Software-Defined Radio (SDR) technology is advantageous as it allows the implementation of modulation and demodulation procedures in software, enabling performance evaluations in various physical mediums, for instance both optical and Radio Frequency (RF). Besides the prototyping need, the growing congestion and limitation of the RF spectrum have led to exploring alternative communication mediums. Visible Light Communication (VLC) technology has emerged as a solution, utilizing an unlicensed optical spectrum without substantial communication competition. The rise in popularity of Light Emitting Diodes (LEDs) for residential and commercial lighting supports this idea, as LEDs can be controlled and employed as information transmitters and its low power consumption. To this aim, studies regarding optical communication and Orthogonal Frequency Division Multiplexing (OFDM), as well as an in-depth explanation of 5G New Radio (NR) numerol ogy were conducted. Therefore, a prototype was prepared and assembled for 5G NR signals generation for downlink via VLC, and for uplink via RF. The experimental results indicated that the coding techniques outlined by 5G NR integrate well with VLC, enabling the use of modulation levels up to 64-QAM. This outcome facilitated error-resistant communication for the transmitted data volume, showcasing a robust hybrid VLC/RF system capable of successfully supports relatively high data rates
Projeto fuse sensor para melhora da qualidade da continuidade de energia elétrica a partir da diminuição do indicador DEC
(Universidade Federal do Espírito Santo, 2024-05-27) Prazeres, Helder Batista de Boa Esperança dos; Co-orientador1; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador3; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador4; ID do co-orientador4; Lattes do co-orientador4; Orientador1; https://orcid.org/; http://lattes.cnpq.br/; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; 1º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 2º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 3º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 4º membro da banca; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
The electrical power distribution systems play a crucial role in social well-being and economic development, providing the foundation for essential services and business sus tainability. However, many components of these systems face technological obsolescence, contributing to power supply failures at critical moments. This situation is further exacer bated in Brazil due to the predominance of bare conductors in its distribution networks and the limited presence of underground networks, making them susceptible to failures caused by external factors. It is observed, however, that these failures in the electrical system can take time to be detected and located, leading to a deterioration in power quality, specifically in the system interruption time, which increases the financial compensation paid by utilities to consumers. To address these challenges, this dissertation presents the Fuse Sensor project, developed in partnership with the company SEVEN (Seven Science Systems Ltda), as an innovative solution incorporating the concepts of Smart Grids and IoT (Internet of Things) technology for the faster location and repair of faults, thus enabling improvements in the efficiency and reliability of electrical systems. The Fuse Sensor is designed to meet the present and future needs of the electrical system, focusing on reducing the SAIDI (System Average Interruption Duration Index), and providing significant gains in compensations. The master’s project approach is structured into three distinct stages: in the first stage, the conception and construction of the Fuse Sensor project are presented, along with the testing procedures; in the second stage, validations of the Fuse Sensor project are conducted, including a comparison of the effectiveness of the communication technologies LoRa, SigFox, and FSK; and finally, in the third stage, an economic analysis is carried out, considering not only the acquisition costs of the innovative equipment but also its economic feasibility for the utilities. By addressing these aspects comprehensively, the Fuse Sensor project aims not only to mitigate the repair time of power supply interruptions but also to promote significant improvements in the quality and reliability of the electrical service. Combining technological innovation and detailed economic analysis, the project seeks not only to meet the current demands of the electrical sector but also to pave the way for a more efficient and sustainable future
Sensores de nível de interface água-óleo em fibra óptica baseados em grades de Bragg
(Universidade Federal do Espírito Santo, 2020-05-27) Ludke, Fabio Giesen; Co-orientador1; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador3; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador4; ID do co-orientador4; Lattes do co-orientador4; Orientador1; https://orcid.org/; http://lattes.cnpq.br/; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; 1º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 2º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 3º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 4º membro da banca; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
This Master Thesis presents the study of fiber Bragg grating (FBG) sensors applied in the measurement of water and oil interface level. Using industrial rubber diaphragms, which has a fiber Bragg grating installed inside, it is possible to measure the level of interface water-oil. The measurement is performed by monitoring the pressure change on each diaphragm caused by the variation in the interface level. The FBG sensors are non-conductive, resistant to electromagnetic interference (EMI) and they are intrinsically safe to be installed in explosive environments. Techniques of FBG inscription known as phase mask and plane-by-plane have been used to manufacture the fiber sensors. Using a spectrometer, the coupled light propagating through the fiber sensor can be interrogated. The analyzes are performed searching for the central wavelength for each FBG used. The stress on the FBG causes a shift in the central wavelength proportional to the level of the interface between the different fluids, for example water and oil. Thus, as water and oil have different densities and depending on the amount of material that is inside the tank, the diaphragms with FBG undergoing higher or lower deformation and causing a proportional wavelength shift variation of the FBG peak. The main materials used in the production of the FBG sensors are silica optical fiber, thermoplastic polyurethane and nitrile rubber. Nitrile rubber corrosion resistant, including use in the oil industry. A methodology was developed for production of FBG sensors with diaphragms printed on the 3D printer and using the nitrile rubber vulcanization. The sensor developed through the vulcanization of nitrile diaphragms with FBG inside was produced using a press system with temperature control. The influence caused by the variation in the diaphragm thickness is observed in the tests with diaphragms produced on 3D printer. This variation doesn’t change the linearity of the system, but change its sensitivity. The measured sensitivities were 7.5 pm/kPa and 5.2 pm/kPa for the diaphragm of 1.2 mm and 2 mm, respectively. The operating range of this interface level sensor varies from 0 to 78 cm. The resolution of the system is approximately 0.01 cm. For interface levels ranging from 0 cm to 78 cm, the standard deviation varied from 0.13 to 0.28, respectively. The average differences calculated for interface levels varying between 0 cm and 78 cm, resulted in standard deviation ranging from 1.09 to 0.43, respectively. It was possible to identify the oil and water interface level in the tests with nitrile diaphragms. As a result, an equation was obtained, where it is possible to determine the interface level through the diaphragm deformation, showing this system has potentiallity to evolve to a product in the near future

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