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1
Zhang, Xiaojing, Lu Ren, Haichuan Yu, Yang Xu, Qingquan Lei, Xin Li i Baojia Han. "Dual-Temperature Evaluation of a High-Temperature Insulation System for Liquid-Immersed Transformer". Energies 11, nr 8 (27.07.2018): 1957. http://dx.doi.org/10.3390/en11081957.
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A high-temperature oil–paper insulation system offers an opportunity to improve the overloading capability of distribution transformers facing seasonal load variation. A high-temperature electrical insulation system (EIS) was chosen due to thermal calculation based on a typical loading curve on the China Southern Power Grid. In order to evaluate candidate high-temperature insulation systems, Nomex® T910 (aramid-enhanced cellulose) immersed in FR3 (natural ester) was investigated by a dual-temperature thermal aging test compared with a conventional insulation system, Kraft paper impregnated with mineral oil. Throughout the thermal aging test, mechanical, chemical, and dielectric parameters of both paper and insulating oil were investigated in each aging cycle. The thermal aging results determined that the thermal class of the FR3-T910 insulation system meets the request of overloading transformer needs.
2
Wei, Yanhui, Wang Han, Guochang Li, Xiaojian Liang, Zhenlu Gu i Kai Hu. "Aging Characteristics of Transformer Oil-Impregnated Insulation Paper Based on Trap Parameters". Polymers 13, nr 9 (22.04.2021): 1364. http://dx.doi.org/10.3390/polym13091364.
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Oil-impregnated insulation paper is an important part of transformers; its performance seriously affects the life of power equipment. It is of significance to study the aging characteristics and mechanism of oil-impregnated insulation paper under thermal stress for transformer status detection and evaluation. In the work, the accelerated thermal aging was carried out at 120 °C, and DP1490, DP787, and DP311 samples were selected to represent the new, mid-aging, and late-aging status of the transformer, respectively. The space charge distribution within the specimens was measured by the pulsed electro-acoustic (PEA) method and the trap parameters were extracted based on the measurement curves. Further, the aging mechanism was studied by molecular simulation technology. A typical molecular chain defect model was constructed to study the motion of cellulose molecules under thermal stress. The experimental results show that the corresponding trap energy levels are 0.54 eV, 0.73 eV, and 0.92 eV for the new specimen, the mid-aging specimen, and the late aging specimen, respectively. The simulation results show that the trapped energy at the beginning of aging is mainly determined by the loss of H atoms. The changes in trap energy in the middle stage of aging are mainly caused by the absence of some C atoms, and the trap energy level at the end of aging is mainly caused by the breakage of chemical bonds. This study is of great significance to reveal the aging mechanism of oil-impregnated insulation paper and the modification of insulation paper.
3
Li, Min, Wei Yao, Xin Gao i Yan Ren. "Temperature simulation of oil-immersed transformerbased on fluid-thermal coupling". Journal of Physics: Conference Series 2503, nr 1 (1.05.2023): 012060. http://dx.doi.org/10.1088/1742-6596/2503/1/012060.
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Abstract The main components of the transformer face overheating and insulation aging caused by electromagnetic losses, which affect their service life. This paper analyzes an oil-immersed transformer with a rated voltage of 800kV based on heat transfer and fluid dynamics principles. The temperature distribution is carried out by magnetic-thermal coupling simulation. The influence of insulation oil flow rate on temperature is analyzed in the thermal field calculation, and the overall temperature rise of transformer and insulating oil is obtained. It turned out that the highest hot spot of the transformer occurs in the low-voltage winding, and the flow speed of insulation oil between the winding is the fastest.
4
Poliakov, M. O., i V. V. Vasylevskyi. "Method for assessing unevenness of cellulose insulation layers aging of power transformers winding". Electrical Engineering & Electromechanics, nr 5 (6.09.2022): 47–54. http://dx.doi.org/10.20998/2074-272x.2022.5.08.
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Introduction. Improving the methods of estimating the insulation aging of the oil-immersed power transformer windings is an urgent task for transformer condition monitoring systems. The scientific novelty of the work is to take into account the uneven distribution of temperature and humidity along the vertical axis of the winding in modeling the aging of insulation and to develop methods for determining the conditions under which the aging rate of insulation in the intermediate layer will exceed aging rate in the hottest layer. The purpose of the work is to evaluate the wear unevenness of cellulose insulation based on modeling the distribution of temperature and humidity along the vertical axis of the power transformer winding. Methods. The transformer winding is mentally divided into horizontal layers of equal height, the reduction of service life is calculated in parallel for all horizontal layers. Layer with the maximum degree of aging for the entire period of operation and storage of the transformer is recognized as determining the reduction in the service life of the insulation of the transformer as a whole. A model of the interaction of winding layers is developed, with determination of temperatures, humidity, relative rate of aging of each layer due to temperature and humidity as a function of traditional design parameters such as load, cooling temperature, heat capacity and thermal resistance of transformer. The index of exceeding the aging rate by the layered method in comparison with this rate for the hottest layer is offered. The method of genetic algorithms determines the conditions for obtaining the maximum value of this index. Results. A computer model has been developed to predict the aging of the cellulose insulation of transformer windings. According to the proposed method, a layer with significantly shorter insulation aging time (in the example, time reduced by 39.18 %) than for the upper layer was determined, which confirms the feasibility of layer-by-layer monitoring and modeling of insulation aging processes of power oil-immersed transformer windings.
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Cao, Jian, Hao Jun Zhou i Su Xiang Qian. "Research on the 3D Temperature Field of Transformer Winding Based on Finite Element Analysis". Advanced Materials Research 129-131 (sierpień 2010): 353–57. http://dx.doi.org/10.4028/www.scientific.net/amr.129-131.353.
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Power transformer is one of the most important electric equipments in power network, its running state has a direct effect on its safe operation of power network. Fault’s occurrence of power transformer probably result in vast hazards or accidents. According to statistics, its over-temperature operation of winding often result in different fault patterns, such as aging, breakdown and its burnt, etc, which has a large proportion in its accidents of power transformer. In this paper, based on the thermal analysis theory, a 3D thermal field model of transformer’s winding and core is respectively established in ANSYS software environment. And its 3D temperature field distribution of power transformer, including winding and core is simulated. Numerical simulated results provide a reliable and convenient reference for its thermal performance analysis of power transformer.is simulated. Numerical simulated results provide a reliable and convenient reference for its thermal performance analysis of power transformer.
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Dong, Bingbing, Yu Gu, Changsheng Gao, Zhu Zhang, Tao Wen i Kejie Li. "Three-Dimensional Electro-Thermal Analysis of a New Type Current Transformer Design for Power Distribution Networks". Energies 14, nr 6 (23.03.2021): 1792. http://dx.doi.org/10.3390/en14061792.
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In recent years, the new type design of current transformer with bushing structure has been widely used in the distribution network system due to its advantages of miniaturization, high mechanical strength, maintenance-free, safety and environmental protection. The internal temperature field distribution is an important characteristic parameter to characterize the thermal insulation and aging performance of the transformer, and the internal temperature field distribution is mainly derived from the joule heat generated by the primary side guide rod after flowing through the current. Since the electric environment is a transient field and the thermal environment changes slowly with time as a steady field under the actual conditions, it is more complex and necessary to study the electrothermal coupling field of current transformer (CT). In this paper, a 3D simulation model of a new type design of current transformer for distribution network based on electric-thermal coupling is established by using finite element method (FEM) software. Considering that the actual thermal conduction process of CT is mainly by conduction, convection and radiation, three different kinds of boundary conditions such as solid heat transfer boundary condition, heat convection boundary condition and surface radiation boundary condition are applied to the CT. Through the model created above, the temperature rise process and the distribution characteristics of temperature gradient of the inner conductor under different current, different ambient temperatures and different core diameters conditions are studied. Meanwhile, the hottest temperature and the maximum temperature gradient difference are calculated. According to this, the position of weak insulation of the transformer is determined. The research results can provide a reference for the factory production of new type design of current transformer.
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Grabko, Volodymyr, Stanislav Tkachenko i Oleksandr Palaniuk. "Determination of temperature distribution on windings of oil transformer based on the laws of heat transfer". ScienceRise, nr 5 (29.10.2021): 3–13. http://dx.doi.org/10.21303/2313-8416.2021.002140.
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Object of research: development of a technology for determining the temperature of the winding of a power oil transformer, in particular, the analysis of thermal processes in the winding of a power transformer during short-term overloads, taking into account the influence of the environment.
Investigated problem: temperature distribution in the winding of a power oil transformer taking into account short-term load surges in the problem of assessing the residual life of the insulation of the transformer winding by temperature aging. The calculation of the temperature distribution in the winding was carried out using the passport data and characteristics of the power oil transformer, including the winding, transformer oil, load currents.
Main scientific results: a mathematical model was calculated, with the help of which the results of temperature distribution in the transformer winding were obtained during short-term load surges or constant work with an increased load. According to the presented model, the analysis of the cooling time of the transformer winding after short-term overloads is carried out. Comparing the results obtained on the simulation model with the known results of experimental studies of the temperature distribution in the winding of a power transformer, the adequacy of the mathematical model is proved. It is shown that the use of the laws of heat transfer in a homogeneous plate to analyze the temperature distribution in the transformer winding is not wrong, but requires clarifications and simplifications.
The area of practical use of the research results: enterprises of the machine-building industry and energy companies specializing in the production and operation of transformer equipment. Innovative technological product: simulation model of heat distribution in a transformer winding, which can take into account the load of the transformer, the effect of the environment on the insulation of the transformer windings.
An innovative technological product: a method for diagnosing the duration of the non-failure operation of a transformer, which makes it possible to ensure trouble-free operation and save money for the repair of transformer equipment.
Scope of application of the innovative technological product: design and development of diagnostic systems for windings of power oil transformers
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Prasojo, Rahman Azis, Rohmanita Duanaputri, Jamik Apriliasari, Rosina Ahda Dini i Devi Soviati Mahmudah. "Review pengaruh penetrasi photovoltaic terhadap loss of life dan kinerja transformator". JURNAL ELTEK 20, nr 2 (28.10.2022): 61. http://dx.doi.org/10.33795/eltek.v20i2.357.
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ABSTRAK
Salah satu peralatan yang penting dalam sistem distribusi tenaga listrik adalah transformator. Penuaan transformator disebabkan oleh kerusakan isolasi yang diakibatkan dari proses degradasi kimia yang terakselerasi oleh oksidasi dan peningkatan suhu. Maka dari itu, untuk menilai loss of life transformator yang paling umum digunakan adalah menggunakan karakteristik thermal transformator. Peningkatan penggunaan photovoltaic (PV) yang mulai menyebar di berbagai daerah adalah salah satu bukti mulai diandalkannya energi terbarukan. Hal ini membawa dampak positif maupun negatif, baik bagi sistem tenaga secara keseluruhan, maupun bagi peralatan listrik. Artikel ini membahas berbagai penelitian terdahulu yang meneliti tentang pengaruh penggunaan PV terhadap penurunan kondisi transformator distribusi. Artikel review ini dibagi menjadi tiga bagian. Yang pertama membahas tentang akibat pemasangan PV yang mempengaruhi kinerja dari isolasi transformator berdasarkan pembebanan yang dialami saat operasi. Yang kedua membahas tentang pengaruh harmonisa yang dihasilkan oleh sistem PV terhadap penuaan transformator. Yang terakhir membahas tentang beberapa penelitian terdahulu yang membahas pendekatan untuk mengatasi harmonisa pada sistem.
ABSTRACT
One of the most important equipment in an electric power distribution system is a transformer. Transformer aging is caused by insulation breakdown resulted from chemical degradation processes that are accelerated by oxidation and increasing temperature. To assess the loss of life of the transformer, the most commonly used is to use the thermal characteristics of the transformer. The increasing use of photovoltaic which is starting to spread in various regions is one proof that renewable energy is starting to be relied on. This has both positive and negative impacts, both for the power system as a whole and for electrical equipment. This article discusses various previous studies that examined the effect of the use of photovoltaic on the deterioration of the distribution transformer condition. This review article is divided into three parts. The first is the effect of PV penetration which affects the performance of the transformer insulation based on the loading during operation. The second is the effect of harmonics generated by the PV system on the transformer aging. The last is to discuss some of the previous studies that proposed methods in reducing harmonics in the system.
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Hong, Shin-Ki, Sung Gu Lee i Myungchin Kim. "Assessment and Mitigation of Electric Vehicle Charging Demand Impact to Transformer Aging for an Apartment Complex". Energies 13, nr 10 (19.05.2020): 2571. http://dx.doi.org/10.3390/en13102571.
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Due to the increasing use of Electric Vehicles (EVs), the effect of the EV charging power demand on the reliability of the power system infrastructure needs to be addressed. In apartment complexes, which have emerged as a common residential type in metropolitan areas and highly populated districts, high charging demand could result in substantial stress to distribution networks. In this work, the effect of EV charging power demand in an apartment complex on the aging of the Distribution Transformer (DT) is studied. A methodology based on the stochastic characterization of vehicle usage profiles and user charging patterns is developed to obtain realistic EV charging demand profiles. Based on the modeled EV charging profile and the transformer thermal model, the effect of different EV penetration ratios on DT aging for an apartment complex in the Republic of Korea is studied. Results for an EV penetration ratio of up to 30% indicated that DT aging could be accelerated by up to 40%, compared to the case without EV charging. To mitigate this accelerated DT aging caused by EV charging, the effectiveness of two integration approaches of Photovoltaic (PV) sources was studied. Based on a case study that included a realistic PV generation profile, it was demonstrated that a significant contribution to DT reliability could be achieved via the operation of PV sources. A more apparent contribution of PV integration was observed with an energy storage installation at higher EV penetration ratios. At an EV penetration ratio of 30%, a maximum decrease of 41.8% in the loss-of-life probability of the DT was achieved. The effects of different PV integration approaches and power management details on DT aging were also studied. The results demonstrate that the EV charging demand could introduce a significant level of stress to DTs and that this impact can be effectively mitigated by installing PV sources. These observations are expected to contribute toward the effective planning of power system infrastructures that support the design of sustainable cities with the widespread use of EVs.
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Jalbert, Rodriguez-Celis, Arroyo-Fernández, Duchesne i Morin. "Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil". Energies 12, nr 20 (18.10.2019): 3969. http://dx.doi.org/10.3390/en12203969.
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This manuscript presents a comprehensive literature review with the aim to provide readers a reference document with up-to-date information on the field of methanol use as a chemical marker. It has been a little more than a decade since methanol was first introduced as a marker for assessing solid insulation condition in power transformers. It all started when methanol was identified in the laboratory during thermal ageing tests carried out with oil-immersed insulating papers and was subsequently also identified in transformer field samples. The first publication on the subject was released in 2007 by our research group. This review covers the methanol fundamentals such as the analytical methods for its determination in transformer oil, which is generally performed by headspace gas chromatography with mass spectrometry or flame ionization as a detector. Current standardization efforts for its determination include ASTM working group 30948 and IEC TC10. Kinetic studies have confirmed the relationship between methanol generation, the number of broken 1,4-β-glycosidic bonds of cellulose and changes in mechanical properties. Laboratory tests have confirmed its stability at different accelerated ageing temperatures. Several utilities have identified methanol during field measurements, case studies on power and some distribution transformers are presented, as well as transformer postmortem investigations. These field-testing results demonstrate its utility in monitoring cellulosic insulation degradation. Recently, a model of methanol interpretation has become available that allows for evaluation of the average degree of polymerization of core type transformer cellulose winding. Methanol has a role as an indicator of cellulosic solid insulation ageing in transformer mineral oil, and it is expected that in the future it will be in routine use by utilities.
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Lim, Dong-Young, i Sungwoo Bae. "Analysis of Load Factor, Hot Spot Temperature, Thermal Aging, and Residual Life of Distribution Transformer with Electric Vehicle Charging Load". Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 32, nr 8 (31.08.2018): 36–44. http://dx.doi.org/10.5207/jieie.2018.32.8.036.
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Khan, Yasir, i Muhammad Iftikhar Khan. "Enhancing Service Life of Power Transformer through Inhibiting the Degradation of Insulating oil by New Approach". International journal of Engineering Works 7, nr 10 (17.10.2020): 369–74. http://dx.doi.org/10.34259/ijew.20.710369374.
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Oil reclamation is a transformer insulation reconditioning technique which may be used as on-line or off-line. However, there is a need of evidence showing the effect of this process on conditions of the paper insulation, which indeed affects the life span of a transformer. This research work focuses on oil reclamation experiment on an old retired distribution transformer. Electrical testing and post-mortem analysis of the transformer were conducted, aimed at investigating the design aspects and collecting information on the insulation conditions prior to the oil reclamation. Temperature and moisture sensors were installed to monitor the conditions within the transformer during the oil reclamation [2]. The experimental process of transformer Oil reclamation was performed into two phases, with regular oil sampling to analyze the changes in key oil parameters, namely acidity number (AN), moisture and breakdown voltage (BV). This was accompanied by paper sampling at the end of each reclamation cycle to study the effects of oil reclamation on properties, particularly moisture, LMA and degree of polymerization. The transformer which was used for the entire experimental process was about 45 years old, 200kVA, 1100 / 415-240V distribution transformer. In order to study the long-term effect of oil reclamation, oil samples were collected from an on-site reclamation exercise performed in a laboratory-accelerated thermal ageing experiment. Oil samples collected before and after the reclamation were aged alongside new oils for comparison [4]. Through the regular monitoring and measurement of oil parameters (AN, moisture and BD strength) over 144 hours and paper parameters (LMA, moisture and DP) at specific stages of phase 1, it was observed that the transformer oil-paper insulation system was significantly improved. The entire research work was performed into two phases (phase 1 and phase 2). The “phase 1” was aimed to improve and restore the oil parameters comparable to the parameters of new oil as specified in “IEC-60296” and its effect on the paper insulation. “Phase 2” was aimed to compare the life span of reclaimed oil filled transformer with the transformer in which aged oil has been replaced by new oil[6]. Effective study of oil reclamation was analyzed through laboratory accelerated aging experiment and real time application on a 45 years old transformer. Through the regular monitoring and measurement of oil parameters (AN, moisture and BD strength) over 144 hours and paper parameters (LMA, moisture and DP) at specific stages of phase1, it was observed that the transformer oil-paper insulation system was significantly improved [15].
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Zhang, Shiling, Lin Gong i Baojia Deng. "Study on Structure Type and Operation Condition of UHVDC Wall Bushing". Journal of Physics: Conference Series 2076, nr 1 (1.11.2021): 012084. http://dx.doi.org/10.1088/1742-6596/2076/1/012084.
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Abstract When the ±800kV UHVDC capacity is increased to 10000MW, the transmission current is 5kA and 6.25kA, which will put forward new requirements for the key technology of UHVDC through wall bushing: in UHV level, the key of through wall bushing lies in the research of basic technology of voltage sharing and field sharing. In the case of large current carrying capacity, the key lies in the basic technology research of current sharing and heat sharing. When the DC wall bushing, converter bushing and outgoing line device operate at the rated voltage, the central conductor is heated due to the carrying large DC current. Therefore, the temperature field distribution inside and at the tail of the bushing core is uneven, and the resistivity is the function of temperature, resulting in the change of resistivity with temperature and the change of potential and electric field distribution with resistivity during operation. Therefore, under the above high current operation conditions, in-depth key technology research is required for the design of bushing current carrying device, calculation of internal potential and electric field distribution, voltage sharing, field sharing, current sharing and heat sharing technology. The combined action of electrical and thermal stress will significantly affect the internal electric field distribution of converter transformer core and accelerate the aging rate of core composite insulation material, which introduces new research topic for the key technology of UHVDC converter bushing. The electric field and voltage distribution of UHVDC bushing are theoretically analyzed, the insulation structure is optimized from the aspects of material and structure, and the manufacturing process and the test technology are deeply and systematically studied.
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Kutin, V. M., M. V. Nikitchuk, V. M. Svitko i O. O. Shpachuk. "AUTOMATION OF THE HEAT STATE ANALYSIS PROCESS HIGH-VOLTAGE CURRENT TRANSFORMERS". METHODS AND DEVICES OF QUALITY CONTROL, nr 2(43) (24.12.2019): 96–110. http://dx.doi.org/10.31471/1993-9981-2019-2(43)-96-110.
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Thermographic control of electrical equipment allows you to draw preliminary conclusions about the technical condition of insulation, contact joints, windings, structural elements and cooling systems of electrical equipment of voltage classes 0.4 ÷ 750 kV. However, it should be borne in mind that the results of temperature measurement and assessment of the thermal state of electrical equipment are influenced by such factors as: environmental conditions, qualifications of personnel performing thermographic control and data interpretation, the need to improve regulatory documents for assessing the thermal state of electrical equipment and develop unified algorithms analysis of the results of thermographic examinations and gradation of the development of defects in electrical equipment.
Modern research in the field of thermographic control of electrical equipment is developing in several directions, namely: the use of automated (stationary or mobile) systems for collecting thermographic data; development of algorithms for processing thermal images that reduce the influence of extraneous noise on the values of the measured temperatures, select the image of the object being examined, select the optimal level of contrast of the thermal image to detect thermal anomalies; using statistical processing of thermal fields of thermal monitoring objects and making decisions about the thermal state of equipment using neural networks, machine learning and expert knowledge. Automation of the analysis of thermographic control data is an urgent scientific and practical task, the solution of which will improve the quality of maintenance, repairs, extension of the operating life and operational management of electrical equipment in conditions of a significant level of aging of the main production assets of electric companies and change of generations of staff.
Measuring current transformers of voltage classes 330 ÷ 750 kV are critical elements in the distribution schemes of electric power and in electric networks, and their technical condition directly affects the reliability of electric networks and power supply to consumers. The paper considers the reasons for the development of defects in current transformers of voltage classes 330 ÷ 750 kV, and also proposes relationships to take into account the influence of the air flow rate and the actual value of the emissivity of the structural element of the current transformers, as well as elements of the algorithms for analyzing data from thermal imaging surveys to reduce the influence of environmental factors and qualification level of the personnel performing the analysis, diagnostic results.
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Liu, Bowen, Fangcheng Lv, Xiaozhou Fan, Hai Xiao i Hanwen Bi. "Insulation Performance and Simulation Analysis of SiO2-Aramid Paper under High-Voltage Bushing". Nanomaterials 12, nr 5 (23.02.2022): 748. http://dx.doi.org/10.3390/nano12050748.
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The long-term safe and stable operation of oil-impregnated paper (OIP) bushings is of great significance to the operation of power systems. With the growth of OIP bushing, its internal insulation will gradually decay. Aramid insulation paper has excellent thermal aging characteristics and its insulation performance can be improved by using nano-modification technology. In this paper, the nano-SiO2 particles were used as the modified additives, and the modified aramid insulation paper was prepared through four steps: ultrasonic stirring, fiber dissociation, paper sample copying and superheated calendering. The microscopic physical morphology and chemical components of the insulation specimens before and after modification were analyzed by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and an OIP bushing model based on the modified aramid insulation paper was constructed and its electric field distribution was analyzed. The simulation results show that the use of SiO2-modified aramid insulation paper can improve the electric field distribution of OIP bushings and increase the operating life of power transformers.
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Liu, Xi-yin, Peng Wang, Yu Lu, Tian-tao Zhang, Li-zhi Wang i Tong-fu Wang. "Identifying the Thermal Storage Stability of Polymer-Modified Asphalt with Carbon Nanotubes Based on Its Macroperformance and Micromorphology". Advances in Materials Science and Engineering 2021 (22.04.2021): 1–17. http://dx.doi.org/10.1155/2021/6637999.
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The thermal storage stability of polymer-modified asphalt (PMA) is the key to avoid performance attenuation during storage and transportation in pavement engineering. However, phase separation of PMA continuously occurs after long-term thermal storage due to the overlooked influence of the phase interface. Two kinds of carbon nanotubes (CNTs) and styrene-butadiene-styrene triblock copolymer (SBS) were selected in this paper to address the aforementioned issue. The segregation test was used to simulate the long-term storage process from 0 to 10 days. Macroperformance included the softening point difference (△SP), irrecoverable compliance (Jnr), recovery rate (R%), and complex modulus (G∗) measured by the softening point test, multistress creep recovery (MSCR) test, and small strain oscillatory rheological test. Microcharacteristics were obtained by the SBS characteristic peak index, SBS-rich phase distribution, polymer swelling degree, and particle characteristics of the SBS-rich phase. They were measured by Fourier-transformed infrared spectroscopy (FT-IR), fluorescence microscopy (FM), and atomic force microscopy (AFM), respectively. Results showed that the optimum CNT amount necessary to obtain an improved thermal storage stability of PMA was 0.5 wt.%. After 10 days of storage, the largest R% of SBS modified asphalt (SBSMA) decreased to 2.24% and the smallest Jnr increased to 0.069 1/kPa, while R% of SBSMA with CNTs was 62.15% and its Jnr was 0.013 1/kPa. R% and Jnr of SBSMA with CNTs showed almost no change after 6 days of storage, implying an effective antirutting performance. The results from the microperformance investigation showed that phase separation of SBS mainly occurred on day 4, while SBS degradation and base asphalt aging led to the worse macroperformance after 10 days of storage. Additional CNTs restrained the SBS-rich phase from floating upward. Meanwhile, a small size of polymer-rich phase and dense network of SBSMA with CNTs were observed in fluorescence microscopy and atomic force microscopy images, thereby exhibiting improved thermal storage stability. Adding CNTs would retard the segregation due to CNT entanglement with SBS.
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Uçar, Banu, Mustafa Bağrıyanık i Güven Kömürgöz. "Influence of PV Penetration on Distribution Transformer Aging". Journal of Clean Energy Technologies 5, nr 2 (2017): 131–34. http://dx.doi.org/10.18178/jocet.2017.5.2.357.
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Rahman Azis Prasojo, Kresna Bayu Priambodo, Anton Setya Aji Herdiansyah, Rohmanita Duanaputri, Slamet Nurhadi i Epiwardi. "Evaluasi Kinerja Sistem Isolasi Transformator Kertas Kraft Terendam Minyak Mineral Pada Sel Uji Penuaan Termal Dipercepat". Elposys: Jurnal Sistem Kelistrikan 9, nr 3 (16.02.2023): 87–92. http://dx.doi.org/10.33795/elposys.v9i3.640.
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The transformer insulation system in the form of oil-immersed paper, is the most important part of a transformer. This isolation system needs to be ensured that it has the appropriate characteristics, and is resistant to stress due to transformer operation. The most commonly used method for evaluating insulation life is the accelerated thermal aging test. Insulating oil-immersed paper is sealed in a vessel with a ratio in the Accelerated Thermal Aging Chamber with a volume capacity of 3600 ml. It takes about 3000 ml of oil to be poured into a tube with a ratio of insulating oil to insulating paper rolled on copper which is 10:1 and then heated in a thermal oven to accelerate aging. This study aims to develop an Accelerated Aging Chamber for evaluating the performance of transformer isolation systems. The developed test cell is able to reach a set-point of 150°C in 16 minutes with on/off control while PID control in 37 minutes with a Human Machine Interface for monitoring and collecting temperature data in real time, and maintaining that temperature until the end of the experimental period. Theresults of the sample will later be tested for the characteristics of the transformer insulation, namely tensile strength, color scale, andbreakdown voltage due to thermal stress.
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Rui-jin Liao, Chao Tang, Li-jun Yang i S. Grzybowski. "Thermal aging micro-scale analysis of power transformer pressboard". IEEE Transactions on Dielectrics and Electrical Insulation 15, nr 5 (październik 2008): 1281–87. http://dx.doi.org/10.1109/tdei.2008.4656235.
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Abdi, Sifeddine, Ahmed Boubakeur, Abderrahmane Haddad i Noureddine Harid. "Influence of Artificial Thermal Aging on Transformer Oil Properties". Electric Power Components and Systems 39, nr 15 (28.10.2011): 1701–11. http://dx.doi.org/10.1080/15325008.2011.608772.
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Gastelurrutia, Jon, Juan Carlos Ramos, Alejandro Rivas, Gorka S. Larraona, Josu Izagirre i Luis del Río. "Zonal thermal model of distribution transformer cooling". Applied Thermal Engineering 31, nr 17-18 (grudzień 2011): 4024–35. http://dx.doi.org/10.1016/j.applthermaleng.2011.08.004.
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Yang, Yong Ming, Xing Mou Liu i Xu Duan. "Analysis for Temperature Rise of a Three-Phase Four Limbs Transformer by Soil Structure with DC Bias". Applied Mechanics and Materials 764-765 (maj 2015): 481–85. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.481.
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In this paper, a method for earth potential computation of layered soil structure is discussed. To calculate thermal field of the transformer with dc bias, simulation models using MAXWELL and COMSOL are proposed. Based on the electromagnetic analysis, electric power loss resulted in temperature rise is calculated. Under the case of normal operation of transformer, a research was carried out to compare the abnormal changes of temperature of transformer. It worked out that if there are different DC parts in transformer, the loss will increase with DC bias and the temperature of transformer core will also increase. If it is increasing continuously and no preventive measures are taken soon, the thermal aging of some parts in transformer will speed up and gradually affect the normal operation of transformer. The research lays the groundwork for further research of transformer DC bias and aging.
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Wang, Wei, Dongxin He, Kai Yang, Shiyuan Liu, Shu Song i Denghui Yi. "Research of the thermal aging mechanism of polycarbonate and polyester film". e-Polymers 17, nr 1 (1.01.2017): 45–56. http://dx.doi.org/10.1515/epoly-2016-0179.
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AbstractInsulating paper is a traditional insulation material used for transformer insulation. Transformer development is not only limited to small sizes and large capacities, but also limited to insulation life as insulating paper cannot withstand high temperatures. Therefore, recent studies have focused on improving the performance of insulation paper and discovering better insulation materials. In this study, two types of polymeric materials, polycarbonate (PC) and polyester film (PET), were chosen for comparative analysis. In order to test whether these two materials could be used in oil-immersed transformers, the PC and PET were placed in transformer oil for thermal aging at 110°C and 130°C, respectively. The thermal cracking processes and fragmentation mechanisms of the PC, PET, and insulation paper were analyzed using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and atomic force microscopy (AFM), as well as their degrees of polymerization and surface morphologies. According to the test results, the initial thermal decomposition temperature of PC and PET are higher than insulation paper and exhibited a better thermal resistance. PC and PET have the potential to substitute insulation paper for large capacity power transformer.
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Widodo, Slamet, Didik Bayu Prasetya i Sri Anggraeni. "Temperature Monitoring System on Distribution Transformer with Web Thermal Camera". JAICT 8, nr 1 (17.03.2023): 200. http://dx.doi.org/10.32497/jaict.v8i1.4317.
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<p><em>Temperature monitoring using a thermal camera is one type of light inspection that is used as an indicator of the health of a transformer. The system can detect the temperature of a transformer without having to stick directly to the surface of the transformer. The results of temperature measurements from the sensor are displayed in the form of images that can be displayed on a web. In this final project, a transformer temperature monitoring system is made that continues to work in real time to measure the temperature of the transformer. This is because changes in the temperature of the transformer can occur at any time. With this system, workers are expected to always monitor the condition of the transformer without having to make onsite visits. In this final project, ESP32 is used as a microcontroller and MLX90641 thermal camera. The use of a thermal camera in this system is caused by several advantages, namely the thermal camera can take the temperature of all parts of the transformer captured on the camera. In addition, the thermal camera has a range of up to seven meters. In this system, the temperature capture is set at the hottest point of all visible camera pixels. This system is also equipped with a notification system that will work when the temperature of the hamster transformer exceeds 60</em><em>℃</em><em>. The normal temperature threshold of the distribution transformer is 30</em><em>℃</em><em>-80</em><em>℃</em><em>. Or the maximum increase in one day of 40</em><em>℃</em><em> </em><em>from the initial temperature. The temperature of the transformer's hottest point will trigger a notification display in a web. So that after receiving a notification the officer can immediately know the temperature of the transformer and immediately take action. From the results of experiments that have been carried out, it is known that the results of measuring the temperature value of the thermometer and sensor have an accuracy rate of 98.8%. In addition, the system also works well, this is indicated by the color difference that occurs when the transformer temperature is in normal and hot conditions. So that from the image displayed, the officer can already know that the measured transformer is in normal or overheated conditions.</em></p>
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Feng, Dawei, Jian Hao, Ruijin Liao, Xin Chen, Lin Cheng i Mengna Liu. "Comparative Study on the Thermal-Aging Characteristics of Cellulose Insulation Polymer Immersed in New Three-Element Mixed Oil and Mineral Oil". Polymers 11, nr 8 (2.08.2019): 1292. http://dx.doi.org/10.3390/polym11081292.
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Cellulose paper, whose main component is cellulose polymer, has been widely used in oil-immersed power transformer that gradually deteriorates during transformer operation. Thermal aging is the main degradation form for cellulose paper immersed in insulation oil (oil–paper insulation) in a transformer. One of the most challenging issues in oil–paper insulation is inhibiting the aging of cellulose paper and extending its life. In this work, a comparative study was conducted on the thermal-aging characteristics of cellulose paper immersed in a novel three-element mixed insulation oil and mineral oil at 130 °C for 150 days. The key parameters of cellulose paper were analysed, including the degree of polymerization (DP), thermal-aging rate, surface colour, and AC breakdown voltage. The furfural content and acidity of the oil, as well as the AC breakdown voltage of the insulation oil were also analysed. The results show that the cellulose paper immersed in novel three-element mixed insulation oil had much higher DP values than that immersed in mineral oil after the same thermal-aging time. The mixed insulation oil could significantly inhibit the thermal aging of cellulose paper and prolong its life. The thermal-aging rate of the cellulose insulation polymer immersed in mixed insulation oil is significantly lower than that immersed in mineral oil, whether in the process of oil–paper insulation continuous aging or in the process of aging after oil replacement with unused insulation oil. The furfural generated by cellulose degradation in the novel three-element mixed insulation oil was also less than that in the mineral oil. The mixed insulation oil had a higher acidity value during the thermal-aging process, which was mainly due to the natural esters in the components of the mixed insulation oil. However, the AC breakdown voltage of the mixed insulation oil was always higher than that of the mineral oil. This study offers a new perspective in inhibiting the thermal aging of cellulose polymer in insulation oil.
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Abdi, Sifeddine, Abderrahmane Manu Haddad, Noureddine Harid i Ahmed Boubakeur. "Modelling the Effect of Thermal Aging on Transformer Oil Electrical Characteristics Using a Regression Approach". Energies 16, nr 1 (29.12.2022): 381. http://dx.doi.org/10.3390/en16010381.
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The effect of thermal aging on the electrical properties of the insulating oil used for transformers has been explored in this experimental work. In particular the dielectric dissipation factor, the resistivity and the breakdown voltage have been measured and correlated. The numerical results predicted by mathematical model and those measured in the laboratory have been compared by using a regression analysis. Experiments on thermal aging were performed on insulating oil (Borak 22, Nynas, Austria) during a period of time of 5000-h at three different temperatures. First, the transformer oil’s dielectric dissipation factor, the resistivity and the breakdown voltage are measured after every 500 h of aging. Then, polynomial and exponential regression expressions are proposed for modelling the oil’s electrical parameters variations with thermal ageing at different aging temperatures and periods. The results show that after thermal aging, the resistivity and the breakdown voltage decrease with thermal aging, however, the dielectric dissipation factor which increases. This trend is similar for all different aging temperatures. The numerical results show close agreement with the measured results for all the samples and all studied properties. The regression model presents strong correlation with high coefficients (>94%).
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Li, Tao, Xiaoping Du, Xuewu Sun i Yuanyuan Song. "Study on the Method of Calculating Temperature Rise of Transformer". E3S Web of Conferences 179 (2020): 01027. http://dx.doi.org/10.1051/e3sconf/202017901027.
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The internal temperature of the transformer is a key parameter to measure the thermal state of the transformer. The service life of the transformer generally depends on the life of the insulating material, and high temperature is the main reason why cause insulation aging, this paper studies the temperature rise of transformer winding hot spot temperature for the key, using the neural network forecasting method, forecasts transformer winding hot spot temperature change rule, calculate the transformer internal temperature rise, provide the temperature of the scientific basis for the safe operation of the transformer.
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Cao, Bin, Ji-Wei Dong i Ming-He Chi. "Electrical Breakdown Mechanism of Transformer Oil with Water Impurity: Molecular Dynamics Simulations and First-Principles Calculations". Crystals 11, nr 2 (27.01.2021): 123. http://dx.doi.org/10.3390/cryst11020123.
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Water impurity is the essential factor of reducing the insulation performance of transformer oil, which directly determines the operating safety and life of a transformer. Molecular dynamics simulations and first-principles electronic-structure calculations are employed to study the diffusion behavior of water molecules and the electrical breakdown mechanism of transformer oil containing water impurities. The molecular dynamics of an oil-water micro-system model demonstrates that the increase of aging acid concentration will exponentially expedite thermal diffusion of water molecules. Density of states (DOS) for a local region model of transformer oil containing water molecules indicates that water molecules can introduce unoccupied localized electron-states with energy levels close to the conduction band minimum of transformer oil, which makes water molecules capable of capturing electrons and transforming them into water ions during thermal diffusion. Subsequently, under a high electric field, water ions collide and impact on oil molecules to break the molecular chain of transformer oil, engendering carbonized components that introduce a conduction electronic-band in the band-gap of oil molecules as a manifestation of forming a conductive region in transformer oil. The conduction channel composed of carbonized components will be eventually formed, connecting two electrodes, with the carbonized components developing rapidly under the impact of water ions, based on which a large number of electron carriers will be produced similar to “avalanche” discharge, leading to an electrical breakdown of transformer oil insulation. The water impurity in oil, as the key factor for forming the carbonized conducting channel, initiates the electric breakdown process of transformer oil, which is dominated by thermal diffusion of water molecules. The increase of aging acid concentration will significantly promote the thermal diffusion of water impurities and the formation of an initial conducting channel, accounting for the degradation in dielectric strength of insulating oil containing water impurities after long-term operation of the transformer.
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Wang, Liang, Chao Tang, Shiping Zhu i Shengling Zhou. "Terahertz Time Domain Spectroscopy of Transformer Insulation Paper after Thermal Aging Intervals". Materials 11, nr 11 (29.10.2018): 2124. http://dx.doi.org/10.3390/ma11112124.
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An accelerated thermal aging process was used to simulate the condition of paper insulation in transformer oil-paper systems. Optical parameters of the insulation paper after various aging intervals were analyzed with terahertz time-domain spectroscopy (THz-TDS) over the range 0.1~1.8 THz. The result shows that the paper had seven absorption peaks at 0.19, 0.49, 0.82, 1.19, 1.43, 1.53, and 1.74 THz, and density functional theory of B3LYP/6-311G+ (d, p) was used to simulate the molecular dynamics of the repeating component (cellobiose) of the cellulose paper. Theoretical spectra were consistent with experiment, which had absorption peaks at 0.18, 0.82, 1.47, and 1.53 THz in the same frequency range. At the same time, the paper samples after various aging intervals had different refractive indexes, and least squares fitting revealed a linear relationship between the degree of polymerization and the refractive index of the paper. Hence, this paper demonstrates that THz-TDS could be used to analyze the aging condition of transformer insulation paper and provides the theoretical and experimental basis for detection.
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Hu, Fang, Li Wen Tang, Song Zhang, Chun Hua Zhang, Dong Feng Chen i Yu Hua Miao. "Effect of Raw Rubber on CH4 Formation from NBR Applied in Transformer Oil". Advanced Materials Research 631-632 (styczeń 2013): 481–85. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.481.
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The formation of CH4 from two kinds of NBR with different raw rubber applied in transformer oil were investigated. In this study, work environment of transformer was simulated，thermal aging tests were conducted for different times in 70°C transformer oil. Surface morphology, the release of CH4, and molecular structure were analyzed by using Gas Chromatography (GC), Scanning Electron Microscope (SEM), and Fourier Transform Infrared analysis (FTIR), respectively. In addition, the swelling property was also discussed in this work. The results illustrated that raw rubber with more content of acrylonitrile had excellent advantages in heat oil aging resistance and the formation of CH4.
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Xu, Yang, Sen Qian, Q. Liu i Z. Wang. "Oxidation stability assessment of a vegetable transformer oil under thermal aging". IEEE Transactions on Dielectrics and Electrical Insulation 21, nr 2 (kwiecień 2014): 683–92. http://dx.doi.org/10.1109/tdei.2013.004073.
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Blue, R., D. Uttamchandani i O. Farish. "Infrared detection of transformer insulation degradation due to accelerated thermal aging". IEEE Transactions on Dielectrics and Electrical Insulation 5, nr 2 (kwiecień 1998): 165–68. http://dx.doi.org/10.1109/94.671924.
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Husin, M. A., Nordiana Azlin binti Othman, N. A. Muhammad, H. Kamarden i M. S. Kamarudin. "Top oil heat distribution pattern of ONAN corn oil based transformer with presence of hot spot study using FEMM". Bulletin of Electrical Engineering and Informatics 8, nr 3 (1.09.2019): 753–60. http://dx.doi.org/10.11591/eei.v8i3.1602.
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Transformer thermal modelling is a crucial aspect to be considered as this may help the determination of heat capacity of transformer. This paper present, simulation study on Oil Natural Air Natural (ONAN) transformer heat distribution pattern with and without presence of hot spot temperature (HST). This paper aims to compare the effects of different HST value at different locations inside the transformer unit as well as to evaluate the top oil thermal behaviour of corn oil as cooling mechanism in a transformer. To achieve aforementioned objectives, three HSTs were introduced to the 30 MVA transformer winding to find the total heat build-up in the top of the transformer tank. The outcome of thermal properties is examined using x-y temperature plot. From the results found that the location of HST affects overall transformer’s temperature. HST at the top of the winding give a significant effect compared to when HST is at the bottom of the winding. It is also evident that the usage of corn oil reduced the temperature distribution of the transformer. The findings suggest that the temperature distribution study especially on transformer is important to monitor in-service transformer in a non-invasive manner.
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Liu, Yunpeng, Shuo Jiang, Xiaozhou Fan i Yuan Tian. "Effects of Degraded Optical Fiber Sheaths on Thermal Aging Characteristics of Transformer Oil". Applied Sciences 8, nr 8 (19.08.2018): 1401. http://dx.doi.org/10.3390/app8081401.
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With the development of fiber optic sensing technology, optical fiber sensors have been widely used in online monitoring of power transformers. To investigate the influence of aging fiber sheaths on transformer oil, two kinds of special optical fibers with thermoplastic polyester elastomer (TPEE) and poly tetra fluoroethylene (PTFE) as sheaths underwent thermally accelerated aging in transformer oil at 130 °C. The volume resistivity, dielectric dissipation factor (DDF), and breakdown voltage of the oil were measured to indicate insulation strength. The water content and acid value of the oil were measured and fitted to predict the aging tends. The thermal aging characteristics of the oil were quantitatively compared and results showed two kinds of optical fibers could exacerbate all the physical and chemical parameters of oil, and the TPEE sheath had a more significant impact on the oil. The reasons contributing to such phenomenon were analyzed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Both TPEE and PTFE were depolymerized in high-temperature transformer oils, producing water and small molecule hydrocarbon groups. The accumulation of small hydrocarbon groups promoted positive feedback of pyrolysis in the oil. The free hydrogen produced by oil pyrolysis increased the acidity of the oil, which in turn increased the solubility of the water produced by sheath depolymerization. The chain depolymerization of TPEE was more severe than that of PTFE, further exacerbating the deterioration of TPEE-containing oil.
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Li, Yan, Yin Jun Guan, Yang Li i Tian Yuan Li. "Calculation of Thermal Performance in Amorphous Core Dry-Type Transformers". Advanced Materials Research 986-987 (lipiec 2014): 1771–74. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.1771.
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The amorphous core dry-type transformer is a new energy-saving transformer. In this paper, a SCBH15-600/10 type amorphous core dry-type transformer is analyzed by 3-D finite element calculation of iron core and winding thermal. Analyzing the temperature distribution characteristics of amorphous transformer, assure the temperature rise highest point. It is in the permitted error between the simulation value and test value. It has important engineering value for the calculation of similar transformer temperature rise; and has certain guiding significance on the amorphous transformer structure design.
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Asfari Hariz Santoso, Ernanda Rizka i Harrij Mukti K. "Analisis Pembebanan Terhadap Perkiraan Umur Transformator Distribusi 20 kV Penyulang Lowokwaru di PT. PLN(PERSERO) UP3 Malang". Elposys: Jurnal Sistem Kelistrikan 9, nr 3 (16.02.2023): 121–26. http://dx.doi.org/10.33795/elposys.v9i3.645.
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One of the most important equipment components in the distribution of electrical energy is the distribution transformer.Distribution transformer if used continuously or continuously it can affect the performance of the transformer. The service life of thetransformer can be reduced more quickly if you do not pay attention to the factors that can make the transformer life shrinkage high. One ofthe causes of the reduced life of the transformer is due to loading. From the eleven transformers, it can be seen that there are differentloading variations, it is expected that the transformer life will remain at normal age. IEC 60354-1, 1991 stipulates the normal life of thetransformer is 20.55 years. The research method used is to perform calculations using the long-time method and 24-hour daily data bycalculating the loading at the time of LWBP and WBP on a 20 kV distribution transformer. Analysis of the calculation results revealed that thenormal condition of the transformer P1385 (68.66 %) winding temperature at LWBP 67.47°C and when WBP 69.45°C compared totransformer P0032 with overload conditions (120.91%) winding temperature when LWBP 60, 88°C and at WBP 119.51°C. From the data onthe lowest loading on the eleven transformers, namely transformer P0527 (41.69%) it is obtained that the estimated real aging age is 0.125and the estimated age of the P0527 transformer is >20 years. Compared to transformer P0032 (120.91%), the estimated real aging age is12,0003 p-u and the estimated age is less than 20 years or 9.5 years. Loading above 100% on the transformer based on the standard IEC60354-1, 1991 if it takes place continuously will cause heating of the transformer windings which can cause the shrinkage process in the lifeof the transformer to be faster.
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Muhammed, Mahmmod Aziz, i Abdul Ridha Ghedayer. "Temperature Distribution in Core and Winding of a Transformer and Its Effect on Performance". Wasit Journal of Engineering Sciences 4, nr 2 (2.11.2016): 17–35. http://dx.doi.org/10.31185/ejuow.vol4.iss2.45.
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In order to reach the maximum power from a transformer and avoid thermal accidents, it is essential to carefully study its thermal behavior. This research is to apply some computational and analytical approaches in order to obtain a temperature distribution within the core and winding of a transformer. Hence its thermal behavior can be analytically and practically predicted. The aim is to optimize transformer operation under various load conditions during the extreme weather of summer season in the southern part of Iraq. The numerical scheme applied which is based on finite difference method has shown to be in good agreement with the empirical data measured on the external finned body of transformer.
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Barros, Amanda M. P., Jorge H. Angelim i Carolina M. Affonso. "Impact on Distribution Transformer Life Using Electric Vehicles with Long-Range Battery Capacity". Energies 16, nr 12 (20.06.2023): 4810. http://dx.doi.org/10.3390/en16124810.
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This paper presents a comparative analysis of the effects of short-range and long-range electric vehicles charging on transformer life. Long-range vehicles are expected to become more common in the future. They have higher battery capacity and charge at higher power levels, modifying demand profile. A probabilistic analysis is performed using the Monte Carlo Simulation, evaluating the transformer hottest-spot temperature and the aging acceleration factor. Residential demand is modeled based on real electricity measurements, and EVs’ demand is modeled based on real data collected from a trial project developed in the United Kingdom. Simulations are conducted considering the influence of ambient temperature analyzing summer and winter seasons and several EV penetration levels. Results show the impacts caused by long-range vehicles are more severe because they charge at higher power levels, especially during winter, when residential demand is higher. For penetration level of 50% during summer, the use of long-range EVs brings a minimum equivalent aging factor of 5.2, which means the transformer aged 124.8 h in a cycle of only 24 h, decreasing its lifetime.
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Korenciak, D., M. Sebok i M. Gutten. "Thermal Measurement and its Application for Diagnostics of Distribution Oil Transformers". ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 62, nr 6 (29.11.2019): 583–94. http://dx.doi.org/10.21122/1029-7448-2019-62-6-583-594.
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In the first part of the paper the theory of infrared radiation and the use of nondestructive measurement of electrical devices by means of thermovision are under analysis. In the second part of paper basic principles and application of non-contact temperature measurement are examined. In the third part of paper thermal processes in distribution oil transformer – temperature in dependence on height of oil transformer and temperature distribution in sectional plan of oil transformer – are considered. In the fourth part of paper, by means of the experimental measurements and subsequent analysis, practical thermal imaging and contact thermal measurements by optical detectors for the diagnosis of distribution oil transformers in the field of mechanical strength of windings are shown. In this paper, we wanted to show out the possibility of using thermal measurements in this field of analysis and detection of quality of winding for distribution oil transformer. It is possible to use these methods to localize places of faults, and they are also applicable for the diagnosis and detection of disorders of the quality of materials and other anomalies during operation of the equipment. By means of the experimental measurements followed by diagnostic analysis the practical use of thermovision and optical sensors for diagnostics of power oil transformers in field mechanical strength and quality of winding is demonstrated.
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Dai, Quanmin, Guowei Mu, Fuwen Tan, Huidong Chen, Xianggang You, Yanxia Liu i Guang Cheng. "The influence of aging time and moisture content on the tensile strength of transformer bushing insulating paper". AIP Advances 12, nr 11 (1.11.2022): 115020. http://dx.doi.org/10.1063/5.0121821.
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The parameter of tensile strength for transformer bushing insulating paper occupies an important position in the structural design and life evaluation of transformer bushing. In order to precisely achieve the effect of aging time and moisture content on the tensile strength of transformer bushing paper, transformer insulating paper samples with a thickness of 0.13 mm were prepared for tensile strength and dielectric strength testing under different moisture contents and aging states. The results show that the tensile strength (MPa) of insulating paper decreases linearly in the range of 0–648 h under accelerated thermal aging at 130 °C. However, there is a more serious exponential decline in the tensile strength (MPa) of insulation paper with its moisture content is boosted. The moisture content in insulation paper is the most important factor for insulation paper deterioration in oil-impregnated paper insulation equipment, which could accelerate the end of insulation service life. The value of capacitance increment ΔC of the insulation paper samples displayed closely linear growth with a moisture content from 0.5% to 5.9%. Strictly controlling the moisture content by monitoring the ΔC value of transformer insulation paper is of significance for prolonging its service life.
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Yuchao, Ma, Mo Juan, Yu Jinshan, Li Xiang i Zheng Zhongyuan. "Study on Sound Field Distribution Rule for Tank Structures of Large Oil-immersed Transformers". E3S Web of Conferences 233 (2021): 01021. http://dx.doi.org/10.1051/e3sconf/202123301021.
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Large oil-immersed transformers are an important part of the transmission and distribution network in power systems. Power transformers are the main noise source of substations. Because of the uneven manufacturing process, aging equipment, long-term operation, and close distance from sensitive points, the problem of transformer noise pollution has become increasingly prominent. In this paper, the transmission and analysis model is established for transformer sound waves on the interface between insulating oil and tank body according to the sound wave propagation rule in complicated medium, and the simplified acoustic simulation model is constructed for large oil-immersed transformers by simulating the vibration noise of transformer core with monopole sound source, with which, the sound field distribution rule inside and outside the transformer tank structure is obtained, and finally, the influence factors for noise distribution are given. The results of the study provide control basis for reducing transformer noise.
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Suwarno, Suwarno, i Rizky Auglius Pasaribu. "Thermal Aging of Mineral Oil -Paper Composite Insulation for High Voltage Transformer". International Journal on Electrical Engineering and Informatics 8, nr 4 (31.12.2016): 820–35. http://dx.doi.org/10.15676/ijeei.2016.8.4.9.
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Wang, Deng, Zhiping Zhu, Li Zhang, Yihua Qian, Wei Su, Tiansheng Chen, Shengping Fan i Yaohong Zhao. "Influence of metal transformer materials on oil-paper insulation after thermal aging". IEEE Transactions on Dielectrics and Electrical Insulation 26, nr 2 (kwiecień 2019): 554–60. http://dx.doi.org/10.1109/tdei.2018.007546.
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Tylavsky, D. J., Qing He, G. A. McCulla i J. R. Hunt. "Sources of error in substation distribution transformer dynamic thermal modeling". IEEE Transactions on Power Delivery 15, nr 1 (2000): 178–85. http://dx.doi.org/10.1109/61.847248.
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Hilshey, Alexander D., Paul D. H. Hines, Pooya Rezaei i Jonathan R. Dowds. "Estimating the Impact of Electric Vehicle Smart Charging on Distribution Transformer Aging". IEEE Transactions on Smart Grid 4, nr 2 (czerwiec 2013): 905–13. http://dx.doi.org/10.1109/tsg.2012.2217385.
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Sarker, Mushfiqur R., Daniel Julius Olsen i Miguel A. Ortega-Vazquez. "Co-Optimization of Distribution Transformer Aging and Energy Arbitrage Using Electric Vehicles". IEEE Transactions on Smart Grid 8, nr 6 (listopad 2017): 2712–22. http://dx.doi.org/10.1109/tsg.2016.2535354.
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Tien, Nguen, i K. H. Gilfanov. "Thermal modelling of oil-filled power transformer TM - 160/10". Power engineering: research, equipment, technology 21, nr 5 (17.12.2019): 141–51. http://dx.doi.org/10.30724/1998-9903-2019-21-5-141-151.
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The results of modeling the thermal characteristics of the dry and oil-filled power transformer TM-160/10 in idle and short circuit modes are presented. The electrical, geometric and thermal characteristics of the TM-160/10 transformer are determined. Computer modeling is performed in the software package ANSYS 17.1. The 2D distributions of temperature and density of heat flows in the transformer in the longitudinal and transverse sections are determined. It is shown that the use of transformer oil for cooling the transformer significantly reduces the temperatures in the active part. The temperature distribution occupies the range of 67-91 °С. Accordingly, the temperature of the most heated part is 91 °C and also corresponds to the low voltage winding. The dependence of the most heated point of the transformer on the operating mode was studied. A formula is proposed for calculating the maximum temperature of a transformer as a function of power loss.
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Sarathi, R., S. Deepa, A. Mishra i Rohitkumar H. Vora. "Investigation into the Effects of Transformer Oil on Fluoro Poly(ether imide)s and their Nanocomposites Films". Journal of Metastable and Nanocrystalline Materials 23 (styczeń 2005): 347–50. http://dx.doi.org/10.4028/www.scientific.net/jmnm.23.347.
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In the present work, the fluoro polyimide films were aged in the transformer oil and the characteristic changes in the film and the transformer oil are analyzed through physico-chemical diagnostic studies. The WAXD and FTIR studies showed that no characteristic change in the material due to thermal aging of the material. The FTIR spectra of the corona aged specimen indicate the formation of new functional groups. The fluorescence spectra of the aged transformer oil suggest dissolvement of heavy ions in the clay material.
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Quan, Yu Sheng, Pu Xin Shi, Shai Gen Han i Ning Chen. "New Research of Transformer Windings Partial Discharge Based on Non-Even Distribution Parameters Model". Applied Mechanics and Materials 521 (luty 2014): 343–46. http://dx.doi.org/10.4028/www.scientific.net/amm.521.343.
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Transformer is the primary equipment of power system. The normal operation of transformers has great significance of the security and stability of a power system. Once partial discharge happened in the winds of a transformer, it will accelerate the aging of the insulation, and may damage the windings. This paper analyzes the effect of partial discharge to transformer windings, and founding a model of non-even distribution parameters. Separate the even distribution parameters model into three parts and partial discharge happens in the second one. The partial discharge leads to changing of the model parameters. And port voltage changes with it. Partial discharge detection achieved according to the changing of port voltage.
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Sun, Xing Tao, i Zhang Mu. "Analysis of Hottest-Spot Temperature Distribution in Cast-Resin Dry-Type Transformer Design". Advanced Materials Research 538-541 (czerwiec 2012): 1015–19. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1015.
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In the cast-resin dry-type transformer design, the determination of winding hottest-spot temperature rise is very important. It determines the safe and cost of transformers. In this paper, a thermal model for analysis of the hottest-spot temperature distribution of cast-resin dry-type transformer has been introduced. The model is based on electrical analogy method and a current source is used to represent the thermal flow source of windings, and a nonlinear resistor is used to represent the effect of air in duct. A 500kVA cast-resin dry-type transformer has been selected and experiment is carried out to demonstrate the model