Electrical and Electronic Engineering, General Materials Science
55
Scopus Publications
Scopus Publications
Monitoring ZnO surge arresters using convolutional neural networks and image processing techniques combined with signal alignment Bruno Vinicius Silveira Araujo, Gustavo Aragão Rodrigues, Johnny Herbert Paixão de Oliveira, George Victor Rocha Xavier, Ulisses Daniel Enes de Souza Lebre, Charles Antony Cordeiro de Araujo, Eduardo Oliveira Freire, Estácio Tavares Wanderley Neto, Tarso Vilela Ferreira Measurement Journal of the International Measurement Confederation, 2025 • Consistent detection and segmentation of thermal anomalies in ZnO Surge Arresters. • Method robust to environmental influences and fluctuations in distance and angle. • Identifies defects through temperature analysis, predicts evolution, enables alerts. • Enhances maintenance and safety, identifies anomalies in various high-voltage gear. • Thermal Profile Alignment for Improved Monitoring of Electrical Equipment. Monitoring and preemptive maintenance of high-voltage electrical equipment play a crucial role in preventing breakdowns and ensuring the seamless operation of power systems. Infrared monitoring stands out due to its convenience, safety protocols, and utilization of temperature as a key indicator for assessing the structural integrity and component health of equipment. This paper introduces a method for monitoring ZnO lightning arresters by analyzing their thermal profiles. The approach involves employing a convolutional neural network and computer vision processes to detect, segment, and extract thermal data from these devices. An alignment algorithm facilitates comparison and classification of operational integrity. The method provides an accurate and comprehensive evaluation of ZnO lightning arresters, enabling continuous monitoring and efficient diagnosis. By analyzing thermal imaging data from a 500 kV substation and conducting laboratory tests on both healthy and intentionally defective equipment, the detection algorithm achieves favorable precision rates (0.861), recall (0.855), mAP50 (0.903), and mAP50:95 (0.615), ensuring precise detection and segmentation. Despite variations caused by thermal imager measurement errors, distance fluctuations, angle deviations, and environmental factors, the algorithm consistently identifies both normally operating and faulty equipment. Notably, when assessing healthy and intentionally defective equipment, the method achieves excellent accuracy in anomalies and its locations.
Electrical Properties of Silver-Silicone Rubber Nanocomposites for High-Voltage Outdoor Insulators Lívia C. dos Passos Araújo, Maria E. Leyva, Estácio T. Wanderley Neto, Alvaro A. A. de Queiroz IEEE Transactions on Dielectrics and Electrical Insulation, 2024 Currently, the selection of high temperature vulcanizing silicone rubber (HTVSiR) formulations resistant to the growth of microorganisms and which suitable electrical properties plays an important role in the manufacture of the polymeric high voltage outdoor insulators (HVOI) with high lifetime. In this work, silver-HTVSiR nanocomposites (AgHTVSiR) formulations are prepared and their electrical and antimicrobial properties are presented. Ag nanoparticles were electrochemically synthesized and characterized by scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), UV-visible (UV-Vis) and X-ray (XRD) spectroscopies. Thermogravimetric (TG/DTG) analysis is undertaken with the purpose of determining the thermal behavior of AgHTVSiR. The complex impedance analyses were conducted to investigate the electrical conduction mechanism of the AgHTVSiR nanocomposites via impedance spectroscopy (EIS) within a frequency range from 0.1 Hz to 0.1 MHz. XRD revealed Ag nanoparticles of 50 nanometers in diameter size. The images of SEM-EDS evinced the homogeneity of Ag nanoparticles dispersion into the HTVSiR matrix. The incorporation of silver nanoparticles does not change the thermal stability of the AgHTVSiR nanocomposite as compared to neat HTVSiR. The AgHTVSiR nanocomposites have maximal values for real part (Z’) at low frequencies. The Z’ is found to decrease as the frequency of the applied alternating electric field increases. Furthermore, there is an improvement in the permittivity values for the AgHTVSiR nanocomposites with an increase in the concentration of 0.1-0.3 wt.% of the Ag nanoparticles. Also, the AgHTVSiR shows excellent antimicrobial efficacy against <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Trichoderma spp</i> fungus. The impedance characteristics of the AgHTVSiR nanocomposite along with its high dielectric permittivity and excellent antimicrobial property make it suitable for application in HVOI.
Probing the Epoxy Insulation of Smoothing Reactors with Graphene Ink Gabriel Henrique de Faria, Lívia C. dos Passos Araújo, Gustavo P. Lopes, Estácio T. Wanderley Neto, Maria Elena Leyva, Alvaro A. A. de Queiroz IEEE Transactions on Dielectrics and Electrical Insulation, 2024 Electrically conductive inks (ECIs) are up to now a growing research field, to create flexible circuits for power engineering. As a result, research into screen printing of conductive electrodes onto fiberglass-epoxy-reinforced laminates (FGERLs) has emerged. In this study, an ECI based on reduced graphene oxide (rGO) is proposed for screen printing of conductive electrodes on FGERL used in insulation of the high-voltage direct current smoothing reactors (HVDCSRs). The electrically conductive reduced graphene oxide ink (ECrGOI) was fabricated by mixing rGO, hyperbranched polyglycerol (HPGL) as an adhesion promoter, and poly (vinyl alcohol) (PVA) as a binding agent. The ECrGOI electrodes exhibited adhesion strength of 3.7 ± 0.3 N/mm2 and conductivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.2.10^{\text {-4}}$ </tex-math></inline-formula> S/cm at percolation threshold starting at less than 7.5 wt.% of rGO. The thermogravimetric analysis (TGA) indicates that ECrGOI exhibited good thermal stability at 400 °C. The attractive electric, thermal, and adhesive properties, combined with the ease of preparation and solution-processing capability, indicate that ECrGOI may have great potential applications in analysis of insulation produced by FGERL used in encapsulation of smoothing reactors.
Measurement of Partial Discharges in Distribution Transformers Immersed in Insulating Liquids Thallia F. D. Fagundes, Estàcio T. W. Neto, Gustavo P. Lopes 2024 IEEE International Conference on High Voltage Engineering and Applications Ichve 2024 Proceedings, 2024 In distribution networks, one of the most common and important equipment is the oil-insulated transformer, which can suffer irreparable damage to the system under load if it presents any failure, especially in the insulation. One of the factors involved in this type of defect is partial discharge (PD), which can cause degradation of the paper and insulating oil, causing inoperability and reducing the useful life of the transformer. Therefore, it is essential to carry out a study on the types of partial discharges present in the transformer and the methods for detecting this phenomenon. In this sense, this work proposes carrying out tests using the electrical method to detect PD in a set of five samples of oil-insulated distribution transformers. To this end, a specific procedure was adopted to carry out the test, as there is no method in Brazil described in standards for distribution transformers immersed in insulating liquids with a voltage lower than or equal to 72.5 kV. In this sense, after the test, it was possible to identify partial discharges in the internal insulation of some transformer samples, in addition to recognizing the need to carry out periodic inspections and predictive maintenance on this equipment.
Development of a Ferroresonance Testing System for Instrument Voltage Transformers: Experimental Investigation in Laboratory and EMTP Modeling Brenno Torres A. Rodrigues, Estácio T. Wanderlay Neto, Thiago A. Nogueira, William T. Agostinho Nascimento 2024 IEEE International Conference on High Voltage Engineering and Applications Ichve 2024 Proceedings, 2024 Ferroresonant oscillations involving voltage transformers (VTs) have become a growing phenomenon, especially in wind parks. The pursuit of practical analysis of ferroresonance has motivated the development of a specialized testing system, combining computational simulations and laboratory tests to explore different aspects of the phenomenon. During the tests, the effects of varying shunt and series capacitances in the circuits were observed, identifying critical values for the occurrence of the phenomenon in each VT. The results demonstrated the testing system's ability to reproduce ferroresonance under laboratory conditions, reflecting real situations in the Electric Power System. The simulation model developed in the Electromagnetic Transients Program (EMTP) proved effective in qualitatively predicting possible modes of ferroresonance, provided that the system parameters are known or estimated.
Development and Testing of Self-Triggering System for Laboratory Impulse Voltage Generators Matheus Pereira, Thiago Silio, Gustavo Lopes, Gabriel Faria, Jansen Villibor, Estácio Wanderley Neto 2024 IEEE Electrical Insulation Conference Eic 2024, 2024 Insulation systems must be designed to withstand lightning overvoltages of different waveforms and should pass through evaluation in high-voltage laboratories. In this context, a lightning impulse voltage generator (Marx generator) became extremely important to check the equipment insulation system. The LAT-EFEI High Voltage Laboratory has the expertise to develop and build its own testing equipment for routine and type tests of distribution transformers. In the past decade, a four-stage Marx impulse generator was successfully designed and built to operate with 400 kV and 20 kJ. Nowadays, laboratory personnel are developing a low-cost triggering system capable of achieving a high repetitiveness triggering and this work presents an evaluation of the prototype chopping time and its durability, as though as the stability of the output voltage to evaluate any alterations.
Higher Electrical Conductivity of Functionalized Graphene Oxide Doped with Silver and Copper (II) Ions Nelson Gustavo Alves Pereira, Maria Elena Leyva Gonzaléz, Alvaro Antonio Alencar de Queiroz, Adhimar Flávio Oliveira, Estácio Tavares Wanderley Neto Energies, 2023 This study presents a new methodology for graphene oxide (GO) synthesis through electrochemical exfoliation of graphite, followed by phthalic anhydride functionalization (PhA-GO) and doping with Cu2+ and Ag+ ions. The synthesis of GO involved the use of an electrochemical cell with H2SO4 as the electrolyte, with a gradual increase in potential from 2.3 V to 10 V. Extensive characterization techniques confirmed the successful incorporation of oxygen-containing functional groups, verifying the oxidation of graphite. PhA-GO functionalization was confirmed by thermogravimetric analysis, Differential Scanning Calorimetry, Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDX), which confirmed the presence of Cu2+ and Ag+ ions. The Scherrer equation determined a grain size of 75.85 nm for GO. The electrical properties exhibited semiconductor and semimetal behavior, particularly in PhA-GO/Ag+ composites, making them suitable for electronic devices over a wide temperature range, presenting a promising pathway for advanced materials in electronic applications.
Technological Development of a Composite Insulator for High Voltage Transmission Line Monitoring Tarso V. Ferreira, Gabriel S. Bolacell, Mauro A. da Rosa, Edson G. da Costa, George R. S. Lira, Jose F. Pissolato, Filipe L. M. Andrade, Regelii S. A. Ferreira, Estacio T. Wanderley Neto, Roberto P. Francisco IEEE Electrical Insulation Magazine, 2023 This article presents an instrumented polymeric insulator with sensors applied to monitor high voltage transmission lines. Practical developments are presented from the laboratory stage until the real transmission line tests.
Partial Discharge Spectrogram Data Augmentation based on Generative Adversarial Networks Lucas de Paula Santos Petri, Emanuel Antonio Moutinho, Rondinele Pinheiro Silva, Renato Massoni Capelini, Rogério Salustiano, Guilherme Martinez Figueiredo Ferraz, Estácio Tavares Wanderley Neto 2019 International Conference on Electrical and Computing Technologies and Applications Icecta 2019, 2019
Feasibility for the utilization of 5 kA distribution arresters Estacio T. Wanderley Neto, Manuel Luis B. Martinez, Aellfcleniton M. M. Diniz, Credson de Salles, Juliano A. Pallaro, Hermes R. P. M. Oliveira 2011 International Symposium on Lightning Protection Xi Sipda 2011, 2011
Core losses profit in rural monophase transformers by means of percent impedance optimization Proceedings International Symposium Modern Electric Power Systems Meps 10, 2010
Economical profits in medium voltage networks obtained by rearrangement of installed transformers Proceedings International Symposium Modern Electric Power Systems Meps 10, 2010
Economical analysis for efficient transformers projects Proceedings International Symposium Modern Electric Power Systems Meps 10, 2010
Monitoring and diagnosis of ZnO arresters Estacio Tavares Wanderley Neto, Edson Guedes da Costa, Ronimack Trajano de Souza, Euler Cassio Tavares de Macedo, Marcelo Jose de Albuquerque Maia IEEE Latin America Transactions, 2006
Electro-thermal simulation of ZnO arresters for diagnosis using thermal analysis 2004 IEEE Pes Transmission and Distribution Conference and Exposition Latin America, 2004
