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Littérature scientifique sur le sujet « Transformers oils »

Auteur : Grafiati

Publié le 1 février 2025

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Articles de revues sur le sujet "Transformers oils"

Ponomarenko, Serhii. « Comparative analysis of oil ageing intensity in 110 kV transformers and 330 kV autotransformers ». Bulletin of the National Technical University "KhPI". Series : Energy : Reliability and Energy Efficiency, n^o 2 (3) (30 décembre 2021) : 124–36. http://dx.doi.org/10.20998/2224-0349.2021.02.06.

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The results of transformer oil ageing intensity analysis in 110 kV transformers and 330 kV autotransformers are presented. Using a mathematical model of variance linear regression analysis (covariance analysis model), applied to the results of periodic tests on 231 transformers of 110 kV and 49 autotransformers of 330 kV, several statistical hypotheses have been tested to estimate the intensity of drift of oil indicators during long-term operation of transformers. The following hypotheses were tested as statistical hypotheses: the hypothesis of a significant systematic drift in the values of oils during long-term operation, which allows assessing the presence of transformer oil ageing processes. The hypothesis of equality of partial angular coefficients for regression models based on test results for each of the oil in individual transformers (regression lines are parallel), which allows estimating the differences in the ageing intensity of oils in individual transformers. The hypothesis that the group averages lie on a straight line, that is, the drift of the oil in the different transformers occurs at the same rate. The hypothesis of equality of partial free terms for regression models based on test results for each of the oil indicators in individual transformers, which allows assessing the presence of differences in the values of oil indicators at the time of commissioning of transformers, that is, the actual presence of differences in the quality of the poured oil. The results of the analysis for both 110 kV transformers and 330 kV autotransformers showed not only an additive and multiplicative bias between individual series of oil parameters, but also a significant systematic component, indicating the aging of transformer oils in the analysed transformers. It was found that the intensity of drift of oil indicators in 110 kV transformers and in 330 kV autotransformers significantly differs, which should be taken into account when building models for the early recognition of the condition of transformer oils by the results of periodic tests.

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Ahmed, Usman Omeiza, Yekini Suberu Mohammed et Nasiru Audu. « Potential Characterization of Bush Mango Oil for Application in Transformer Insulation ». Asian Journal of Engineering and Applied Technology 12, n^o 1 (29 juin 2023) : 51–54. http://dx.doi.org/10.51983/ajeat-2023.12.1.3685.

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In recent times, the suitability of some oils from edible fruits as a replacement for mineral oils used in transformers has been proven in different literature. The use of edible oils as transformer insulation fluid gives rise to the concept of green insulation in transformers. Research in the use of edible oil in the production of transformer oil has been one of the major researches in high voltage engineering. The existence of paucity of knowledge on the use of bush mango oil as dielectric fluid in transformers led to the idea of this research work. Therefore, this study focuses on the investigation of the suitability of using Irvingia Gabonensis Oil (IGO) for insulation in power transformers. From the series of analyses conducted, it has been established that the Irvingia Gabonensis (Bush Mango) oil is not suitable for transformer insulation oil. This is because the biobased green oil produced presented characteristics that are not suitable to match the standards recommended by the International Electrochemical Commission (IEC) and the American Society for Testing and Materials (ASTM).

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Serhii, Zaitsev, et Kishnevsky Victor. « IMPROVEMENT OF THE METHOD OF DIAGNOSTICS OF HIGH-VOLTAGE TRANSFORMERS VOLTAGE BASED ON THE RESULTS OF CHROMATOGRAPHIC ANALYSES OF TRANSFORMER OILS ». Collection of scholarly papers of Dniprovsk State Technical University (Technical Sciences) 2, n^o 43 (25 décembre 2023) : 100–111. http://dx.doi.org/10.31319/2519-2884.43.2023.11.

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The relevance of the work is due to the need to improve methods for diagnosing high-voltage oil-filled voltage transformers with paper-oil electrical insulation, which makes it possible to solve the problems of monitoring the technical condition, finding the place and determining the causes of failure (malfunction), and predicting the technical condition of this equipment on the basis of appropriate diagnostic software. The aim of the work is to ensure the reliability of operation of high-voltage oil-filled voltage transformers with paper-oil electrical insulation by improving the method of their diagnosis based on the results of analyses of samples of mineral transformer oils by gas chromatography. In accordance with the research objective, the following tasks were solved: 1. Determine the content of such dissolved diagnostic components in samples of mineral transformer oils from high-voltage oil-filled voltage transformers of NKF-110, NKF-220, NKF-330 types as gases H2, CH4, C2H6, C2H4, C2H2, CO, CO2, O2, N2; additive "Ionol"; furan compounds (2-furyl alcohol; 2-furfural; 2-acetylfuran; 5-methyl-2-furfural) and the sum of their concentrations. 2. The basic procedures for diagnosing high-voltage oil-filled voltage transformers based on the results of analyses of mineral transformer oil samples with the determination of the content of dissolved diagnostic components in them were improved. For the diagnosis of high-voltage oil-filled voltage transformers based on the results of gas chromatographic analyses of samples of mineral transformer oils from this equipment, it is recommended to use the following methods: "Limit level of concentrations", "Tabular method", "Graphic images of defects", "ETRA", "Duval triangle", "Visual inspection after disassembly of high-voltage oil-filled voltage transformers". To determine the degree of danger of the development of the identified probable defects, the method of determining the "Relative growth rate of dissolved gas concentrations" can be used. The prospect of practical application of the results of the work is to ensure the reliability of operation of high-voltage oil-filled voltage transformers by improving the method of their diagnosis based on the results of analyses of samples of mineral transformer oils with simultaneous determination of the content of dissolved gases, the additive "Ionol", furan compounds by gas chromatography.

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Ghani, Sharin Ab, Mohd Shahril Ahmad Khiar, Imran Sutan Chairul et Muhammad Imran Zamir. « Effect of repeated electrical breakdowns on mineral and natural ester insulating oils ». Bulletin of Electrical Engineering and Informatics 10, n^o 6 (1 décembre 2021) : 2989–96. http://dx.doi.org/10.11591/eei.v10i6.3258.

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Transformer insulating oils are exposed to repeated electrical discharge or breakdowns inside power transformers. Durability tests are conducted to analyze the ability of oil to resist decomposition due to such high electrical stresses. With the increasing demand for alternative insulating oils for oil-immersed transformers, it is worthy to compare the performance of different types of insulating oils (conventional mineral-based insulating oil and natural ester-based insulating oil) under repeated electrical breakdown. In this paper, the AC breakdown voltage of different mineral-based and natural ester-based insulating oils is reported. Durability tests were conducted based on the AC breakdown voltage behavior of insulating oils after 50 electrical breakdown shots. The AC breakdown voltage of each insulating oil sample was assessed according to the ASTM D1816 standard test method. Based on the results, it can be concluded that the dissimilarity in chemical composition of the insulating oils has a significant effect on the AC breakdown voltage behavior of these oils under repeated electrical breakdowns.

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M.Jamail, N. A., N. A. Azali, E. Sulaiman, Q. E. Kamarudin, S. M. N. S. Othman et M. S. Kamarudin. « Breakdown Characteristic of Palm and Coconut Oil with Different Moisture ». Indonesian Journal of Electrical Engineering and Computer Science 12, n^o 1 (1 octobre 2018) : 363. http://dx.doi.org/10.11591/ijeecs.v12.i1.pp363-369.

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<p>Oils acts as insulation and cooling agent in the transformer. Petroleum-based oils are widely used in transformers due to their qualified properties as good insulation materials. Unfortunately, the used of petroleum-based oils has adverse effects on environment in the event of any failure to transformers such as tank leakage or explosions. Therefore, researchers have been studied and have found environmentally friendly oil that is suitable as substitutes in transformer. Thus, breakdown voltage tests using direct current and alternating current with the addition of different water content were performed to identify the potential of palm oil and coconut oil in the transformer isolation system. Refined, Bleached and Deodorized oil (RBDPO) and coconut oil samples were selected to be test in this study. The oil samples were test by varies the gap distance of test cell electrode and the level of water content. As a conclusion, RBDPO oil has greater breakdown voltage test under DC breakdown voltage test in term of increment of the gap distance.</p>

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Prasad, D., et S. Chandrasekar. « EFFECT OF NANO-SiO2 PARTICLES ON PARTIAL DISCHARGE SIGNAL CHARACTERISTICS OF FR3 TRANSFORMER OIL ». JOURNAL OF ADVANCES IN CHEMISTRY 13 (7 février 2017) : 6208–17. http://dx.doi.org/10.24297/jac.v13i0.5687.

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Liquid insulation for high voltage transformer applications based on natural esters derived from abundantly available vegetable oils are becoming popular in recent times. Since these natural ester based oils have environmental advantages and superior thermal performance, electrical utilities are slowly replacing the conventional mineral oils with natural ester based vegetable oils. FR3 oil, which is a soya based natural ester oil with superior dielectric and thermal characteristics, is becoming popular as an alternate insulating medium for high voltage transformers. With recent developments in nanotechnology field, it is possible to enhance the dielectric performance characteristics of natural ester based oils, which is a major constraint for high voltage transformer applications. However few research reports are only available in the area of nanofluids based on natural esters for high voltage insulation applications. In depth analysis and collection of large data base of insulation performance of natural ester based vegetable oils is important to improve the confidence level over nano-fluids based on natural esters. Considering these facts, in the present work, partial discharge characteristics of nano-SiO2 modified FR3 oil at different electrode configurations are investigated at different %wt filler concentrations. Important parameters such as partial discharge inception voltage, stable PD formation voltage, partial discharge amplitude at different voltage magnitude and PD signal frequency characteristics are evaluated. From the results, it is observed that the partial discharge performance of FR3 oil is significantly improved with the addition of nano-SiO2 filler. Since in recent times FR3 oil is commercially used in many transformers, these results will be useful for enhancing the dielectric strength of high voltage transformers.

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Ab Ghani, Sharin, Zulkarnain Ahmad Noorden, Nor Asiah Muhamad, Hidayat Zainuddin et Mohd Aizam Talib. « A Review on the Reclamation Technologies for Service-Aged Transformer Insulating Oils ». Indonesian Journal of Electrical Engineering and Computer Science 10, n^o 2 (1 mai 2018) : 426. http://dx.doi.org/10.11591/ijeecs.v10.i2.pp426-435.

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Power transformers are the backbone of electricity transmission and distribution systems throughout the world. The price of power transformers is exorbitant (costing millions of dollars per unit) and therefore, frequent maintenance is necessary to ensure that these systems are highly reliable during their operation. The service life of mineral insulating oils is typically 30 to 40 years for power transformer applications. However, all insulating oils (regardless of their type) are subjected to thermal, electrical and chemical degradation, which will deteriorate the oil-paper insulating system and consequently reduce the capability of the oil as an electrical insulator. For these reasons, service-aged insulating oils are treated by two types of processes (i.e. reclamation and reconditioning) in order to prolong the service life of these oils. Reclamation (regeneration) is used to treat insulating oils with high levels of acidity and sludge. In this paper, a brief review on the reclamation technologies used to treat service-aged insulating oils is presented, covering various aspects such as the standard test methods that need to be complied with, the types of adsorbents used to reduce acidity and sludge of the used insulating oils, as well as the findings of several key studies related to the evaluation of the effectiveness of the reclamation process. This review will indeed benefit researchers and practitioners in this field since it provides an overall picture of the recent progress in reclamation technologies for service-aged transformer insulating oils

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Vysogorets, S. P., A. N. Nazarychev et A. A. Pugechov. « METHOD FOR EXPERIMENTAL DETERMINATION OF THE LIQUID DIELECTRIC RESOURCE AND MEASURES FOR ITS RESTORATION ». Kontrol'. Diagnostika, n^o 254 (2019) : 36–41. http://dx.doi.org/10.14489/td.2019.08.pp.036-041.

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The theoretical foundations of changes in the transformer oil quality characteristics, depending on the aging degree, are presented. The introduction of a new indicator of the exploitational transformer oils quality – “stability against oxidation” – is substantiated as a way of solving the scientific and technical problem of assessing the resource characteristics of a transformer insulating system. In order to select the best measures to maintain the quality of power transformers insulating oils, a newly developed “Method for the Experimental Determination of the Luquid Dielectric Resource and Measures for its Restoration” is presented.

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Zdanowski, Maciej. « Streaming Electrification Phenomenon of Electrical Insulating Oils for Power Transformers ». Energies 13, n^o 12 (22 juin 2020) : 3225. http://dx.doi.org/10.3390/en13123225.

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The subject matter of this study was the problem of the ECT (electrostatic charging tendency) of mineral insulation oils during their flow. The electrostatic charges generated may lead to partial discharges, and as a consequence, to the breakdown of a power transformer insulation system. In this study, the results of the ECT of mineral oils used in transformers were compared. The method of streaming electrification of insulation liquids using a flow-through system was used. The influence of flow speed, temperature, and the pipe material on the values of the electrification current and volume charge density qw were analyzed. The results obtained in this study should be taken into account regarding the operation of power transformers.

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Boukounacha, Ahmed Yassine, Boubakeur Zegnini, Belkacem Yousfi et Tahar Seghier. « Factors affecting the thermal conductivity of dielectric nanofluids for use as alternative fluids in power transformers ». South Florida Journal of Development 5, n^o 9 (2 septembre 2024) : e4314. http://dx.doi.org/10.46932/sfjdv5n9-001.

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The high heat transfer capabilities of dielectric fluids used in power transformers are considered one of the most important properties responsible for increasing the efficiency of these devices, as these oils transfer the heat generated from the internal parts of the transformer to the external environment. The application of nanotechnology in liquid insulators will increase the heat transfer rates through the thoughtful incorporation of nanoparticles (NPs) in these insulating media. Nanofluids (NFs) have higher thermal conductivity compared to conventional insulating oils found in power transformers, which nominates them as promising alternatives in the field of high voltage. This paper focuses on the thermal conductivity capabilities of dielectric nanofluids as well as the analysis of different factors affecting thermal conductivity. It also presents some theoretical models to determine the thermal conductivity of NFs with the possibility of applying these dielectric nanofluids to improve the heat transfer performance of power transformer.

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Plus de sources

Thèses sur le sujet "Transformers oils"

Phillips, Lyndal, University of Western Sydney, of Science Technology and Environment College et of Science Food and Horticulture School. « Analysis of polychlorinated biphenyls in transformer oils ». THESIS_CSTE_SFH_Phillips_L.xml, 2002. http://handle.uws.edu.au:8081/1959.7/766.

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Polychlorinated Biphenyls (PCBs) were seen as a significant engineering advance when first commercially produced in 1929. They were used as insulators and cooling fluids in electrical transformers and capacitors. There are 209 PCB congenors that are chemically and thermally stable with low inflammability and reactivity. However,they are also highly toxic, suspected carcinogens and bioaccumulate in the food chain. Due to these characteristics they are listed by the United Nations as one of the sixteen worlds persistent organic pollutants POPs). By international agreement, undertaken by the UN, the production of PCBs has been banned and gradually their use will be phased out. Several tests and procedures are discussed in some detail in this research.
Master of Science (Hons)

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Martin, Daniel. « Evaluation of the dielectric capabilities of ester based oils for power transformers ». Thesis, University of Manchester, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694702.

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Khan, Imad Ullah. « Assessment of the performance of ester based oils in transformers under the application of thermal and electrical stress ». Thesis, University of Manchester, 2009. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:189512.

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Soares, Valdeir Ribeiro. « Requisitos e restrições do uso do óleo vegetal de tungue como líquido isolante para transformadores elétricos de distribuição de média tensão ». Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/3192.

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Devido à necessidade de se desenvolver um líquido isolante renovável em alternativa ao uso de óleo mineral em transformadores, a comunidade cientifica e empresas do segmento de energia buscam desenvolver óleos vegetais para essa aplicação. Sendo que, atualmente os óleos vegetais utilizados de forma comercial em transformadores possuem base vegetal que competem com a indústria alimentícia. Dessa forma o presente trabalho tem como objetivo verificar a possibilidade do óleo de tungue ser utilizado em transformadores de distribuição, face sua alta capacidade produtiva e o mesmo não competir com a alimentação humana. Para isso, foi utilizado como referência, as características físico-químicas da norma NBR 15422 – Óleo vegetal isolante para equipamentos elétricos, que é a norma responsável para uso também em transformadores. Visando reduzir a acidez do óleo de tungue para níveis normatizados, foi realizado processo de adsorção dos componentes polares através de Terra Fuller. O tratamento com Terra Fuller se mostrou ineficaz para o óleo de Tungue bruto, sendo assim, foi realizado um processo industrializado para refino do óleo para reduzir sua acidez. Para verificação das características do óleo de Tungue, foi construído um protótipo de transformador e realizado os ensaios dielétricos de rotina conforme norma NBR 5356, sendo que não foram detectadas falhas elétricas e ainda, foram obtidos níveis de resistência de isolamento próximos aos obtidos em transformadores que utilizam óleos isolantes mineral e vegetal comercializados para equipamentos elétricos.
Due to the need to develop a renewable insulating liquid alternative to mineral oil used in transformers, the scientific community and energy sector companies look for to develop vegetable oils for this application. Whereas, now the vegetable oils used in transformers in a commercial way have vegetable based competing with human food. Thus, the present work aims to verify the possibility of tung oil be used in distribution transformers, given its high production capacity and it does not compete with human food. For this, was used as a reference, the physicochemical characteristics of the NBR 15422 - vegetable insulating oil for electrical equipment, which is the standard responsible for use also in transformers. Aiming to reduce the acidity of tung oil at standardized levels was performed adsorption process of polar components through Fuller Earth. Treatment with Fuller Earth was ineffective for raw tung oil, therefore, an industrial process for oil refining was carried out to reduce its acidity. For verification of tung oil characteristics, a transformer prototype has been built and performed routine dielectric tests according to NBR 5356, with electrical faults were not detected and also were obtained resistance of isolation levels close to those obtained in transformers use vegetable and mineral insulating oils marketed for electrical equipments.

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Khelifa, Hocine. « Propriétés diélectriques des nanofluides : tenue diélectrique, électrisation statique, décharges partielles et décharges surfaciques ». Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2024. http://www.theses.fr/2024ECDL0048.

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Cette thèse explore le développement, la préparation et la caractérisation des nanofluides (NFs) pour améliorer la performance diélectrique des liquides d'isolation couramment utilisés dans les transformateurs de puissance, y compris les esters synthétiques, les esters naturels et les huiles minérales en incorporant différents types de nanoparticules (NPs). Ces dernières sont conductrices (Fe3O4, C60, et Gr), semiconductrices (ZnO et CuO) et isolantes (Al2O3, ZrO2, SiO2 et MgO). L'étude vise à améliorer les propriétés diélectriques, notamment la tension de claquage en courant alternatif, la résistance aux décharges partielles, la tendance à la charge électrostatique et les caractéristiques de décharge de surface. Une analyse complète couvrant l'évolution historique, les techniques de préparation (méthodes en une ou deux étapes) et les mécanismes de stabilisation essentiels pour obtenir des nanofluides stables avec des propriétés diélectriques optimales est présentée. Les protocoles de préparation des NP, ainsi que les différents montages expérimentaux et les méthodes utilisées pour les caractériser sur le plan diélectrique, sont ensuite décrits. L'impact des caractéristiques des NPs, telles que le type, la taille, la concentration et le traitement de surface, sur les performances diélectriques des liquides de base est systématiquement évalué. Les données expérimentales sont ensuite analysées à l'aide d'outils statistiques tels que le test d'adéquation d'Anderson-Darling et l'analyse de probabilité de Weibull, et les tensions correspondant à des niveaux de risque de 1 %, 10 % et 50 % ont été déterminées. Les mécanismes impliqués dans l'amélioration/la détérioration de la tension de claquage en courant alternatif sont discutés. Les résultats expérimentaux indiquent que les nanofluides (NFs) améliorent de manière significative les propriétés diélectriques en réduisant l'activité de décharge partielle, la tendance à la charge électrostatique et la longueur d'arrêt des décharges de surface. Cette amélioration est obtenue en influençant la mobilité des charges dans les liquides. Les nanoparticules (NPs) conductrices et isolantes, en particulier Fe3O4 et Al2O3, présentent des avantages substantiels qui peuvent contribuer à atténuer les événements de rupture et à prolonger la longévité des équipements. En outre, l'interaction des nanoparticules aux interfaces solide-liquide affecte les comportements de décharge de surface, ce qui renforce le rôle des nanofluides dans l'amélioration de la durabilité de l'isolation
This thesis explores developing, preparing, and characterizing nanofluids (NFs) to enhance the dielectric performance of insulation liquids commonly used in power transformers, including synthetic esters, natural esters, and mineral oils by incorporating different types of nanoparticles (NPs). These later being conducting (Fe3O4, C60, Gr), semi-conducting (ZnO and CuO), and insulating (Al2O3, ZrO2, SiO2, and MgO). The study aims to improve dielectric properties, including the AC breakdown voltage, partial discharge (PD) resistance, electrostatic charging tendency, and surface discharge characteristics. A comprehensive analysis covering the historical evolution, preparation techniques (one-step and two-step methods), and stabilization mechanisms essential for achieving stable nanofluids with optimal dielectric properties is presented. The preparation protocols of NFs, as well as the various experimental set-ups and methods used to characterize them dielectrically, are then described. The impact of NP characteristics, such as the type, size, concentration, and surface treatment, on the dielectric performance of base liquids is systematically assessed. The experimental data are then analyzed using statistical tools such as the Anderson-Darling goodness-of-fit test and Weibull probability analysis, and the voltages corresponding to 1%, 10%, and 50% risk levels were determined. The involved mechanisms in the improvement/deterioration of AC breakdown voltage are discussed. The experimental results indicate that nanofluids (NFs) significantly enhance the dielectric properties by reducing partial discharge activity, the electrostatic charging tendency, and the stopping length of surface discharges. This improvement is achieved by influencing charge mobility within the liquids. Both conducting and insulating nanoparticles (NPs), particularly Fe3O4 and Al2O3, demonstrate substantial benefits, which can help mitigate breakdown events and extend equipment longevity. Additionally, the interaction of nanoparticles at solid-liquid interfaces affects surface discharge behaviors, further supporting the role of nanofluids in enhancing insulation durability

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Schlicker, Darrell Eugene. « Flow electrification in aged transformer oils ». Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38844.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
Includes bibliographical references (p. 317-348).
by Darrell Eugene Schlicker.
M.S.

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Wilson, Gordon. « Characterisation of mineral transformer oil ». Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392140.

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Cargol, Timothy L. (Timothy Lawrence) 1976. « A non-destructive transformer oil tester ». Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/81576.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.
Includes bibliographical references (leaves 62-63).
A new non-destructive test of transformer oil dielectric strength is a promising technique to automate and make more reliable a diagnostic that presently involves intensive manual efforts. This thesis focuses some of the issues that must be understood to bring the test from the laboratory to the field. Emphasis is placed on reliability and safety by exploring any effect the test has on the transformer oil, the mechanical parameters necessary to give optimal reliability, and failsafe electronics.
by Timothy L. Cargol.
M.Eng.

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O'Sullivan, Francis M. (Francis Martin) 1980. « A model for the initiation and propagation of electrical streamers in transformer oil and transformer oil based nanofluids ». Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40504.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.
Includes bibliographical references (p. 305-309).
The widespread use of dielectric liquids for high voltage insulation and power apparatus cooling is due to their greater electrical breakdown strength and thermal conductivity than gaseous insulators, while their ability to conform to complex geometries and self-heal means that they are often of more practical use than solid insulators. Transformer oil is a particularly important dielectric liquid. The issues surrounding its electrical breakdown have been the subject of extensive research. Much of this work has focused on the formation of electrical streamers. These are low-density conductive structures that form in regions of oil that are over-stressed by electric fields on the order of 1 x 108 (V/m) or greater. Once a streamer forms it tends to elongate, growing from the point of initiation towards a grounding point. The extent of a streamer's development depends upon the nature of the electrical excitation which caused it. Sustained over-excitation can result in a streamer bridging the oil gap between its point of origin and ground. When this happens an arc will form and electrical breakdown will occur. Streamers can form due to both positive and negative excitations. Positive streamers are considered more dangerous as they form at lower electric field levels and propagate with higher velocities than negative streamers. Historically, the modeling of streamer development has proved to be a very difficult task. Much of this difficulty relates to the identification of the relevant electrodynamic processes involved. In the first section of this thesis a comprehensive analysis of the charge generation mechanisms that could play a role in streamer development is presented.
(cont.) The extent of the electrodynamics associated with Fowler-Nordheim charge injection, electric field dependent ionic dissociation (the Onsager Effect) and electric field dependent molecular ionization in electrically stressed transformer oil are assessed and it is shown that molecular ionization, which results in the development of an electric field wave, is the primary mechanism responsible for streamer development. A complete three carrier liquid-phase molecular ionization based streamer model is developed and solved for a positive needle electrode excitation using the COMSOL Multiphysics finite element simulation suite. The modification of the liquid-phase molecular ionization model to account for the two-phase nature of streamer development is described and the performance of both the liquid-phase and gas/liquid two-phase models are compared with experimental results reported in the literature. The second section of this thesis focuses on the insulating characteristics of transformer oil-based nanofluids. These nanofluids, which can be manufactured from a variety of materials, have been shown to possess some unique insulating characteristics. Earlier experimental work has shown that oil-based nanofluids manufactured using conductive nanoparticles have substantially higher positive voltage breakdown levels than that of pure oil. A comprehensive electrodynamic analysis of the processes which take place in electrically stressed transformer oil-based nanofluids is presented, which illustrates how conductive nanoparticles act as electron scavengers in electrically stressed transformer oil-based nanofluids. As part of this analysis, a completely general expression for the charging dynamics of a nanoparticle in transformer oil is developed.
(cont.) The solutions for the charging dynamics of a range of nanoparticle materials are presented and the implications these charging dynamics have on the development of streamers in oil-based nanofluid is explained. To confirm the validity of the electrodynamic analysis, the electric field dependent molecular ionization model for streamers in pure oil is modified for use with transformer oil-based nanofluids. This model is solved for nanofluids manufactured using conductive and insulating particles and the results that are presented confirm the paradoxical fact that nanofluids manufactured from conductive nanoparticles have superior positive electrical breakdown performance to that of pure oil. The thesis concludes by exploring the possibility of developing simplified streamer models for both transformer oil and transformer oil-based nanofluids, which are computationally efficient and can be solved quickly meaning that they can be used as practical design tools.
by Francis M. O'Sullivan.
Ph.D.

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TANTEH, DERICK NJOMBOG, SHAFIQ YOUSEF AL-LIDDAWI et DANIEL SSEKASIKO. « PROPERTIES OF TRANSFORMER OIL THAT AFFECT EFFICIENCY ». Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2664.

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Abstract. Transformer explosions caused by dielectric failure account for over 50% of the disasters. The aim of this thesis is to examine, compare and outline the differences, in function, as dielectric insulators, vegetables oil has, with respect to the mineral oil used in high-power transformers. We will first consider the vegetable oil which has less dielectric capabilities than the mineral oil used in power transformers. Later in the experiments, we will focus mainly to examine the breakdown voltage property, as we try to alter some properties of the respective oils used. Considering the fact that vegetable oil has low viscosity, with its chemical compounds constituting less molecular masses compared to mineral oil, we endorse, from our experimental findings, that mineral oil is indeed worthy and reasonable to be used as a dielectric in high power transformers. In this write-up, we have considered eleven transformer oil properties. In the experiment proper, we considered only the acidity, whose concentration in the transformer oil increases with aging if the transformer, moisture, and a ‘suitable’ impurity like NaOH(aq). At first glance, one would be tempted to think, as we were, that since the increase in acid content of the oil deteriorates its dielectric performance, an increase in alkaline content of the transformer oil, would increase its dielectric ability; reversing the acid effect. But as we see in the results from our experiments, this is false. We think that the visible degradation of the insulating property of the oil, with the introduction of NaOH(aq), is because it acts as an impurity to suitable dielectric function. From the experiments, the heating procedures resulted in the production of toxic gases. This indicated the actual loss of chemical structure and significant breakage of chemical bonds. The resulting chemical composition of the oil does not produce the same dielectric properties as the initial oil sample. Also, here has been considerable inconsistency in the addition of NaOH(aq) or HCl(aq) to both oils. We only added HCl(aq), before every measurement, in two of the experiments. The other experiments were either with moisture, or a single addition of 2cm3 of either HCl(aq) or NaOH(aq) before heating; after which several measurements were taken, at specific intervals, as the mixture cools. We did so, in the latter, in which we had only one addition of a 2cm3 chemical, because in real life, given the short time frame of the experiment, the total amount of acid in the oil has a negligible change. So, in a functioning heated transformer, within a short time frame, there is actually deterioration in oil insulation properties

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Livres sur le sujet "Transformers oils"

Proctor & Redfern Limited. et Canada. Environmental Protection Directorate. Office of Waste Management., dir. Options for the treatment/destruction of polychlorinated biphenyls (PCBs) and PCB-contaminated equipment. Ottawa : Environment Canada, 1991.

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IEEE Power Engineering Society. Power System Instrumentation and Measurements Committee., dir. IEEE guide for diagnostic field testing of electric power apparatus-- : Part 1 : Oil filled power transformers, regulators, and reactors. New York : Institute of Electrical and Electronics Engineers, 1995.

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International, Conference on Development of 1200 kV National Test Station (2010 New Delhi India). International Conference on Development of 1200 kV National Test Station, 29-30 September 2010, New Delhi, India : Proceedings. New Delhi : Central Board of Irrigation & Power, 2010.

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N, Mathur G., Chadha R. S et India. Central Board of Irrigation and Power., dir. Manual on transformers (oil immersed). New Delhi : Central Board of Irrigation & Power, 2007.

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IEEE Power Engineering Society. Transformers Committee. et IEEE Standards Board, dir. IEEE guide for loading mineral-oil-immersed power transformers rated in excess of 100 MVA (65⁰ C winding rise). New York, N.Y : Institute of Electrical and Electronics Engineers, 1991.

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IEEE Power Engineering Society. Transformers Committee., Institute of Electrical and Electronics Engineers. et IEEE-SA Standards Board, dir. IEEE trial-use standard general requirements and test code for dry-type and oil-immersed smoothing reactors for DC power transmission. New York, N.Y., USA : Institute of Electrical and Electronics Engineers, 2000.

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Gnanasekaran, Dhorali, et Venkata Prasad Chavidi. Vegetable Oil based Bio-lubricants and Transformer Fluids. Singapore : Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-4870-8.

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Institute of Electrical and Electronics Engineers., IEEE Power Engineering Society. Transformers Committee., IEEE Standards Association et IEEE Standards Board, dir. IEEE trial-use guide for the detection of acoustic emissions from partial discharges in oil-immersed power transformers. New York : Institute of Electrical and Electronics Engineers, 2000.

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Gruntovich, Nadezhda. Technical diagnostics of electrical equipment. ru : INFRA-M Academic Publishing LLC., 2023. http://dx.doi.org/10.12737/1891041.

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The textbook presents a modified theory of vibration diagnostics of rolling bearings. The methods of technical diagnostics of electrical equipment insulation without high-voltage tests are given. The physical nature of the electric arc inside the tank of an oil-filled transformer is revealed for the first time. The methods of complex technical diagnostics of electric motors and power oil-filled transformers are described. Expert systems of technical diagnostics of electrical equipment are considered. Conditions of damage to cables by partial discharges are revealed. Meets the requirements of the federal state standards of higher education of the latest generation. The textbook is intended for students, undergraduates and postgraduates of energy specialties of universities, as well as for specialists in technical diagnostics of equipment of thermal and nuclear power plants, industrial enterprises.

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Center, Langley Research, dir. Comparing parameter estimation techniques for an electrical power transformer oil temperature prediction model. Hampton, Va : National Aeronautics and Space Administration, Langley Research Center, 1999.

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Chapitres de livres sur le sujet "Transformers oils"

Beroual, Abderrahmane, Christophe Perrier et Jean-Luc Bessede. « Insulating Oils for Transformers ». Dans Dielectric Materials for Electrical Engineering, 347–78. Hoboken, NJ USA : John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118557419.ch16.

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Şerban, Mariana, Livia Sângeorzan et Elena Helerea. « On the Mineral and Vegetal Oils Used as Electroinsulation in Transformers ». Dans IFIP Advances in Information and Communication Technology, 435–42. Berlin, Heidelberg : Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-11628-5_48.

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Cirujano, Pablo, et Enrique Otegui. « Eco-design in Oil Immersed Transformers ». Dans Lecture Notes in Electrical Engineering, 87–96. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-58172-9_10.

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Elzagzoug, E., et G. R. Jones. « Chromatic Analysis of High-Voltage Transformer Oils Data ». Dans Advanced Chromatic Monitoring, 149–58. First edition. | Boca Raton : CRC Press, 2020. | Series : : CRC Press, 2020. http://dx.doi.org/10.1201/9780367815202-20.

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Schreiter, Sebastian, Holger Lohmeyer et Peter Werle. « Multidimensional Investigation of Transformer Oil Properties ». Dans Lecture Notes in Electrical Engineering, 705–13. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-31676-1_67.

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Sufian, A. T., E. Elzagzoug et D. H. Smith. « Optical Chromatic Monitoring of High-Voltage Transformer Insulating Oils ». Dans Advanced Chromatic Monitoring, 47–58. First edition. | Boca Raton : CRC Press, 2020. | Series : : CRC Press, 2020. http://dx.doi.org/10.1201/9780367815202-7.

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Vahidi, Behrooz, et Ashkan Teymouri. « Unused Mineral Insulating Oil ». Dans Quality Confirmation Tests for Power Transformer Insulation Systems, 1–11. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-19693-6_1.

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Vahidi, Behrooz, et Ashkan Teymouri. « In-Service Mineral Insulating Oil ». Dans Quality Confirmation Tests for Power Transformer Insulation Systems, 13–36. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-19693-6_2.

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Mariprasath, T., Victor Kirubakaran, Perumal Saraswathi, Kumar Reddy Cheepati et Prakasha Kunkanadu Rajappa. « Study on Alternate Oil Properties ». Dans Design of Green Liquid Dielectrics for Transformers : An Experimental Approach, 5–29. New York : River Publishers, 2024. http://dx.doi.org/10.1201/9788770042086-2.

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A. Japar, N. Suhaila, Mohd Aizudin Abd Aziz et N. W. Abdu Rahman. « Conversion of Waste Transformer Oil into Grease ». Dans Advances in Waste Processing Technology, 23–35. Singapore : Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4821-5_2.

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Actes de conférences sur le sujet "Transformers oils"

Kurniawan, Mashudan, Aris Fadillah, Unzhil Latif Jayyid, Suwarno, Rachmawati, Aji Lesmana, Susiana Mutia et Leandra Agung Tri Radi Putra. « Comparative Study on Aging Characteristics of Various Insulating Oils in Transformers ». Dans 2024 6th International Conference on Power Engineering and Renewable Energy (ICPERE), 1–6. IEEE, 2024. https://doi.org/10.1109/icpere63447.2024.10845658.

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Phoongen, Fariz, Narisara Thongboonchoo, Chanaphat Lertweeranontharat, Prakob Kitchaiya, Nattapong Mantree et Norasage Pattanadech. « Removal of Free Fatty Acids and Impurities from Palm Oil for Use in Bio-Transformer Oils ». Dans 2024 IEEE 14th International Conference on the Properties and Applications of Dielectric Materials (ICPADM), 266–70. IEEE, 2024. http://dx.doi.org/10.1109/icpadm61663.2024.10750651.

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Kozlov, Vladimir K., Diliya M. Valiullina et Ilsur M. Minegaliev. « Aging Mechanisms of Transformer Oils and Their Aging Markers ». Dans 2024 International Ural Conference on Electrical Power Engineering (UralCon), 49–54. IEEE, 2024. http://dx.doi.org/10.1109/uralcon62137.2024.10718956.

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Beldjilali, Abdeslem, et Slimane Bouazabia. « Contaminated Transformer Oil Electrification Behaviour ». Dans 2024 3rd International Conference on Advanced Electrical Engineering (ICAEE), 1–4. IEEE, 2024. https://doi.org/10.1109/icaee61760.2024.10783348.

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Ebrahimnia-Bajestan, Ehsan, Mohammad Arjmand et Hani Tiznobaik. « Effect of Waste Vegetable Oil on Cooling Performance and Lifetime of Power Transformers ». Dans ASME 2020 14th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/es2020-1716.

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Abstract During the operation of a power transformer, a large amount of heat is generated due to the electrical and magnetic energy losses in its core and windings, causing a temperature rise in transformers. This generated heat is known as the main factor for aging the electrical insulating system of a transformer. In this research, we numerically studied the ability of a vegetable-based oil — as an alternative coolant for the petroleum-based oils — on the cooling performance of a power transformer. The studied oil was a biodiesel produced from waste cooking vegetable oils, having lower viscosity compared to traditional mineral oils. We also calculated the aging rate of the transformer in the presence of the biodiesel. The results indicated that compared to the mineral oil, the average hotspot temperature of the transformer is 3 degrees lower when the biodiesel was used. The life expectancy of the transformer with the vegetable-based oil was also significantly longer than the case with mineral oil. In conclusion, this study provided a sustainable way to use an eco-friendly material produced from a waste resource as an alternative insulating liquid for the cooling of power transformers.

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Swiecichowski, Patrick, Miles Nevills, Ethan Languri, Jim Davidson, Lino Costa et David Kerns. « Characterization of Functionalized Nanodiamonds in Mineral Oils for Transformer Applications ». Dans ASME 2023 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/imece2023-113527.

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Abstract The use of transformers for varying the voltage in a power grid is heavily limited and determined by its thermal management. This thermal management is largely based on the mineral oil that surrounds the core of the transformer, this mineral oil dissipates the heat that is produced by the core of said transformer. The current mineral oil that is used is a dielectric, that restricts the ability to conduct electricity, and is widely used since the thermal properties of the mineral oil are high compared to the low cost of the mineral oil itself. The improvement in the heat transfer of the transformer not only increases its lifespan but also increases the capacity for the throughput of power. With electrification being an increasing focus, the demands on the power grids are only increasing as time passes. Nanodiamond-enhanced mineral oils present a potentially novel and surprisingly inexpensive solution to increase the heat transfer rate from transformers fins, leading to an increase in grid throughput capability. By using the nanodiamond-enhanced mineral oil, potentially little to no alterations to the current design of the transformer would be necessary. Because all that would need to be changed would be the mineral oil surrounding the core, this means that most transformers currently in use could also be enhanced, reducing the cost by not manufacturing another replacement transformer and just replacing the mineral oil inside. This is also a passive solution compared to active solutions such as circulating pumps for the oil dissipating the heat through an exchanger, so there is no added mechanical complexity or electrical consumption. This paper investigates the physical and thermal properties of functionalized nanodiamonds in mineral oils at various concentrations. A detailed discussion of multiple properties of the fluids will be performed including: how the introduction of the functionalized nano-diamonds to the mineral oil affects the thermal conductivity the mineral oil experiences, how the change in the mineral oil affects the viscosity and how this change in viscosity might impact the function of the transformer, how this change in the mineral oil affects the specific heat capacity and the potential impact this might have on the longevity and efficiency of the transformer system, and lastly, how the density of the mineral oil is impacted and what kind of implications or complications this might pose for the prolonged use in transformers. This paper will also take a look into the changes that adding the functionalized nano-diamonds to the mineral oil will have on the oil itself, microscopically, and the interactions it might experience by using Scanning Electron Microscopy, Dynamic Light Scattering, and X-ray Diffraction.

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Kolarski, Dejan, Valentina Vasović, Jelena Janković, Draginja Mihajlović et Jovana Bošnjaković. « PROCEDURE FOR REMOVING ELEMENTAL SULFUR FROM THE OIL OF POWER TRANSFORMERS - REDUCING THE RISK OF POWER TRANSFORMERS FAILURES ». Dans 14. Savetovanje o elektrodistributivnim mrežama Srbije, sa regionalnim učešćem, R—1.07. CIRED Liaison Committee of Serbia, 2024. http://dx.doi.org/10.46793/cired24.r-1.07dk.

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During the past years, there has been an increase in the number of power transformer failures worldwide linked by the presence of corrosive sulfur compounds in mineral insulating oil, leading to the formation of deposits of highly conductive copper sulfide or silver sulfide. In oils in operation, a highly reactive elemental sulfur, in a form of eight atom molecule of sulfur, S8, with a strong affinity for silver can be detected which present a significant threat to the contacts of the on load tap changer (OLTC). The high-temperature reactivation process of adsorbents during or after the regeneration process of mineral insulating oils leads to the contamination of insulating oil with elemental sulfur. The paper presents an innovative low-temperature process for the efficient removal of S8 from mineral insulating oil, based on the application of a small amount of iron particles coated with copper on its surface as a key component of the reagent mixture which is dispersed in polyethylene glycol. Intensive mixing of the reagent mixture with mineral insulating oil at temperatures below 100°C enables the complete removal of S8 from the oil. High process efficiency, the removal of S8 from the initial 15 mg/kg to levels below the detection limit, is achieved by using a small amount of the reagent mixture relative to the oil mass (<0.2 wt.%), in laboratory conditions and on a pilot scale experiments. Applying this process and subsequent treatment with adsorbents, insulating oils with improved physical, chemical and electrical characteristics are obtained, suitable for further use in power transformers. This procedure reduces potential environmental and economic risks associated with power transformer failures. The next phase will involve further process optimization and industrial plant implementation.

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Kolarski, Dejan, Valentina Vasović, Jelena Janković, Draginja Mihajlović et Jovana Bošnjaković. « PROCEDURE FOR REMOVING ELEMENTAL SULFUR FROM THE OIL OF POWER TRANSFORMERS - REDUCING THE RISK OF POWER TRANSFORMERS FAILURES ». Dans 14. Savetovanje o elektrodistributivnim mrežama Srbije, sa regionalnim učešćem,, I—1.07. CIRED Liaison Committee of Serbia, 2024. http://dx.doi.org/10.46793/cired24.i-1.07dk.

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Villaverde, M. Zabalegui, et D. Urquiza Cuadros. « Evaluation of Physical-Chemical Characteristics of Mineral Oils Mixed with Synthetic Esters ». Dans 2019 6th International Advanced Research Workshop on Transformers (ARWtr). IEEE, 2019. http://dx.doi.org/10.23919/arwtr.2019.8930179.

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Vasović, Valentina, Draginja Mihajlović, Jelena Lukić, Marko Cvijanović, Zoran Nikolić et Dejan Žukovski. « DINAMIKA RASPODELE VODE U IZOLACIONOM SISTEMU ENERGETSKIH TRANSFORMATORA – METODE ZA PRAĆENJE I INTERPRETACIJU REZULTATA MERENJA I STATISTIČKA RASPODELA OVLAŽENOSTI TRANSFORMATORA U REPUBLICI SRBIJI ». Dans 5. Savetovanje Srpskog nacionalnog komiteta Međunarodnog saveta za velike električne mreže. Srpski nacionalni komitet Međunarodnog saveta za velike električne mreže CIGRE Srbija, 2023. http://dx.doi.org/10.46793/cigre35.0121v.

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A long-term monitoring of operation of power transformers by oil analysis provides a better assessment of transformers condition, and also leads to the improvements of existing and the development of new test methods. The introduction of new testing methods and accumulation of the knowledge from practice, after a certain time, requires revisions of the standards for monitoring and diagnosing the condition of transformers. The international standardization body IEC, TC 10 committee, currently conducts the revision of the standard IEC 60422/2013 "Mineral insulating oils in electrical equipment - Supervision and maintenance guidance". One of the main topics relates to the recommended values for water content in the oil during transformer operation, and also: the advantages and disadvantages of on-line monitoring of water content in oil via capacitive sensors installed in transformers and usefulness of calculation of "normalized" water content in oil at temperature of 20 ° C, which currently exists in Annex A of the relevant standard. This paper gives a graphical presentation of long-term monitoring of water content in oil in specified power transformers. A comparison of the values of absolute water content in oil measured in the laboratory by direct Karl Fischer titration measurements, values of "normalized" water content at 20 ° C and values of estimated moisture content in the paper, based on moisture equilibrium charts and electrical measurements, depending of operating temperature of the oil is presented. During load variations of the transformer and/or variations of the ambient temperature, there are consequent changes in the operating temperature of the oil, which results in a constant migration of moisture between the solid insulation and the oil. The paper analyzes the hysteresis curves of the moisture content in the oil obtained during heating and cooling in dry and wet power transformers. The paper also presents comparative results of water content in the oil obtained in laboratory conditions and measured by on-line sensors, in the correlation of transformer load, ambient temperature and operating oil temperature. Statistical processing of data available in the database of the Electrical Engineering Institute Nikola Tesla obtained the statistical distribution of estimated water content in the paper of generator step up (GSU) transformers and distribution power transformers (voltage level 110 kV and 35 kV). The presented results indicate that in the population of GSU transformers and distribution transformers of voltage level 110 kV the transformers are mainly dry (water content in paper is less than 2%), while in population of distribution transformers voltage level 35 kV the majority of transformers have moderately wet insulation (water content in paper is between 2% and 4%). Based on the results shown, conclusions were drawn regarding conditions that should be met in order to obtain reliable and accurate results of absolute water content in the oil measurements. The value of "normalized" water content in the oil (at 20 ° C), when monitored as a trend analysis, may can be a useful tool in assessing of wetness of the insulation system of transformer, and also in planning of the drying of the insulation system. The paper gives guidelines for successful monitoring of water content in the oil, and wetness of the insulation system, via online sensors.

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Rapports d'organisations sur le sujet "Transformers oils"

Will Shale Impede or Accelerate the Global Energy Transition ? King Abdullah Petroleum Studies and Research Center (KAPSARC), juin 2021. http://dx.doi.org/10.30573/ks--2021-wb02.

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United States (U.S.) shale has transformed oil market dynamics in ways we never thought possible. Shale oil has transformed the oil supply curve through massive supply shocks, such as the rapid increase in tight oil production over the past decade, alongside productivity and technology developments.

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