Articles de revues : « Power transformers design »

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Orosz, Tamás, et István Vajda. « Design Optimization with Geometric Programming for Core Type Large Power Transformers ». Electrical, Control and Communication Engineering 6, n^o 1 (23 octobre 2014) : 13–18. http://dx.doi.org/10.2478/ecce-2014-0012.

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Abstract A good transformer design satisfies certain functions and requirements. We can satisfy these requirements by various designs. The aim of the manufacturers is to find the most economic choice within the limitations imposed by the constraint functions, which are the combination of the design parameters resulting in the lowest cost unit. One of the earliest application of the Geometric Programming [GP] is the optimization of power transformers. The GP formalism has two main advantages. First the formalism guarantees that the obtained solution is the global minimum. Second the new solution methods can solve even large-scale GPs extremely efficiently and reliably. The design optimization program seeks a minimum capitalized cost solution by optimally setting the transformer's geometrical and electrical parameters. The transformer's capitalized cost chosen for object function, because it takes into consideration the manufacturing and the operational costs. This paper considers the optimization for three winding, three phase, core-form power transformers. This paper presents the implemented transformer cost optimization model and the optimization results.

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Orosz, Tamás. « FEM-Based Power Transformer Model for Superconducting and Conventional Power Transformer Optimization ». Energies 15, n^o 17 (25 août 2022) : 6177. http://dx.doi.org/10.3390/en15176177.

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There were many promising superconducting materials discovered in the last decades that can significantly increase the efficiency of large power transformers. However, these large machines are generally custom-made and tailored to the given application. During the design process the most economical design should be selected from thousands of applicable solutions in a short design period. Due to the nonlinearity of the task, the cost-optimal transformer design, which has the smallest costs during the transformers’ planned lifetime, is usually not the design with the highest efficiency. Due to the topic’s importance, many simplified transformer models were published in the literature to resolve this problem. However, only a few papers considered this preliminary design optimization problem in the case of superconducting transformers and none of them made a comparison with a validated conventional transformer optimization model. This paper proposes a novel FEM-based two-winding transformer model, which can be used to calculate the main dimension of conventional and superconducting transformer designs. The models are stored in a unified JSON-file format, which can be easily integrated into an evolutionary or genetic algorithm-based optimization. The paper shows the used methods and their accuracy on conventional 10 MVA and superconducting 1.2 MVA transformer designs. Moreover, a simple cost optimization with the 10 MVA transformer was performed for two realistic economic scenarios. The results show that in some cases the cheaper, but less efficient, transformer can be the more economic.

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Баширов, М., Mussa Bashirov, Азат Хисматуллин, Azat Hismatullin, И. Прахов et I. Prahov. « Increasing of Power Oil-Filled Transformers’ Operation Reliability and Safety ». Safety in Technosphere 7, n^o 2 (23 janvier 2019) : 15–21. http://dx.doi.org/10.12737/article_5c35cc6e2354f7.79418159.

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This paper is devoted to the currently urgent problem — increasing reliability and safety for power oil transformers’ operation with considerable long and short overloads through cooling systems’ efficiency upgrading, allowing increase the power oil transformers’ operation safety, engine life, reliability and economical efficiency. Statistical data on fault causes for transformers of different voltage classes and lifecycles have been given. Based on the study of statistical data it has been established that one of the main causes for transformers faults was the inefficiency of oil cooling systems during the summer period of operation and with considerable long and short overloads. For improvement of efficiency of power oil transformers’ cooling system the agitation of cooling oil by circulating sulfur hexafluoride (SF6) and subsequent sulfur hexafluoride cooling with a thermoelectric cooler is proposed. The system of sulfur hexafluoride circulation and cooling switches on automatically at considerable long and short overloads. The design and operation of the proposed cooling system for oil transformers have been considered. A series of laboratory experiments for transformer oil cooling in a power transformer’s tank without and with a compressor has been carried out. Graphs of temperature-time relationship at natural cooling and when using agitation have been presented. The coefficients of transformer oil’s thermal diffusivity and heat transfer at various distances from heating element have been experimentally defined. The mathematical problem of a heat flux distribution in a rectangular parallelepiped has been considered, a solution for thermal conductivity equation in the power transformer’s tank, which is a rectangular parallelepiped, has been presented. A laboratory setup design has been described in detail. Brands of used thermocouples, compressor and analog-digital converter have been presented. Use of the upgraded cooling system will allow increase the transformers operation safety and reliability.

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Su, Biao, Li Xue Li, Yi Hui Zheng, Xin Wang, Yan Liu et Chang Li Dang. « Design and Analysis of PCB Rogowski Coil Current Transformer ». Applied Mechanics and Materials 672-674 (octobre 2014) : 984–88. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.984.

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Electronic current transformers are more suitable for the development of power system compared with traditional electromagnetic current transformers. Rogowski coil current transformer is one of three electric current transformers. According to the measurement principle of Rogowski coils, the equivalent circuit of PCB Rogowski coils is analyzed. By using four PCB Rogowski coils combined, a PCB Rogowski coil current transformer is designed and tested. The results show that the designed PCB Rogowski coil transformer has good linearity and high sensitivity and measurement accuracy and it can meet the requirement of power system.

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Zhang, Zhan, et Cai Xia Gao. « Hardware Design of Online Monitoring System for Power Transformer Malfunction ». Applied Mechanics and Materials 143-144 (décembre 2011) : 618–21. http://dx.doi.org/10.4028/www.scientific.net/amm.143-144.618.

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Power transformers are vital equipments in the grid and their reliability can affect the security of the grid directly. So it is always necessary to monitor the power transformers online. The study designed a multi-parameter online monitoring system for power transformer malfunction utilizing DSP and computer technology. The paper mainly introduced the design and component selection of online monitoring circuit for partial discharge, dielectric loss, gas component in oil and iron core's grounding current. The result showed that this system can diagnose most the malfunctions in power transformers with satisfactory property.

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ÖZÜPAK, Yıldırım. « Performing Structural Design and Modeling of Transformers Using ANSYS-Maxwell ». Brilliant Engineering 2, n^o 2 (29 janvier 2021) : 38–42. http://dx.doi.org/10.36937/ben.2021.002.005.

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Transformers have attracted great interest since they have been used due to their robustness and application in power systems. Therefore, the nominal values of transformers grow even more in larger power systems due to the constantly increasing power demand. Many types of research are carried out to increase the performance characteristics of transformers and their compatibility with power systems. There are different methods and analysis tools for these studies. One of them is ANSYS@Maxwell, which performs analysis based on the Finite Element Method (FEM). With this program, the design, modeling, analysis, and performance evaluation of the transformer in a high-performance simulation environment can be achieved through effective strategic modeling. In this study, the design and modeling of a three-phase core-type transformer with coils and terminals are explained in detail in ANSYS @ Maxwell simulation platform. Besides, the transformer models examined were adapted using ANSYS@MAXWELL software based on the finite element method. Analyzes are performed to estimate the core-losses, leak-losses, DC-losses, and winding-eddy current losses-of transformers with this program. A large number of meshes were used in FEM analysis of 2D and 3D models to examine the losses in detail.

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Ćućić, Branimir, Nina Meško, Martina Mikulić et Dominik Trstoglavec. « Design improvements in modern distribution transformers ». Journal of Energy - Energija 63, n^o 1-4 (2 juillet 2022) : 74–81. http://dx.doi.org/10.37798/2014631-4165.

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In the paper design improvements of distribution transformers related to improved energy efficiency and environmental awareness are discussed. Eco design of transformers, amorphous transformers, voltage regulated transformers and transformers filled with ester liquids are analyzed. As a consequence of growing energy efficiency importance, European Commission has adopted new regulation which defines maximum permissible levels of load and no-load losses of transformers with rated power ≤ 3150 kVA, and minimum peak efficiency index for transformers with rated power > 3150 kVA up to 40 MVA. The impact of new regulation on the design and economy of transformer is presented. Amorphous transformers, with up to 70 % lower no-load losses in comparison to the conventional transformers, could be an alternative with respect to energy efficiency. Although their initial price is higher than the price of conventional transformers, some studies show that they might have economic advantages. The increasing penetration of distributed energy sources can cause an increase in voltage variations in low voltage networks. To keep the voltage within limits defined by EN50160, voltage regulated distribution transformers could be used. Although mineral oil has been used as a dielectric fluid in transformers for many years, there are some environmentally friendlier alternatives – natural and synthetic ester-based fluids.

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Chisepo, Hilary Kudzai, Leslie David Borrill et Charles Trevor Gaunt. « Measurements show need for transformer core joint details in finite element modelling of GIC and DC effects ». COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 37, n^o 3 (8 mai 2018) : 1011–28. http://dx.doi.org/10.1108/compel-11-2016-0511.

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Purpose This paper aims to improve the finite element modelling of transformers subjected to DC excitation, by including core joint details. Design/methodology/approach Geomagnetically induced currents (GICs) or leakage DC can cause part-cycle, half wave saturation of a power transformer’s core. Practical measurements and finite element matrix (FEM) simulation were carried out using three laboratory-scale, untanked single-phase four limb transformers resembling real power transformers in terms of the core steel and parallel winding assemblies. “Equivalent air gaps” at the joints, based on AC measurements, were applied to the FEM models for simultaneous AC and DC excitation. Findings Measurements confirm that introducing equivalent air gaps at the joints improves the FEM simulation of transformers carrying DC. Research limitations/implications The FEM simulations based on the laboratory transformers are exemplary, showing the difference between modelling core joints as solid or including equivalent air gaps. They show that, for more representative results, laboratory transformers used for research should have mitred core joints (like power transformers). Originality/value This research shows why joint details are important in FEM models for analysing transformer core saturation in the presence of DC/GICs. Extending this, other core structures of power transformers with mitred joints should improve the understanding of the leakage flux during half-wave saturation.

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Sopov, Anatoliy I., et Aleksandr V. Vinogradov. « The Heating System of Agricultural Facilities Using Excess Heat Power Transformers ». Elektrotekhnologii i elektrooborudovanie v APK 67, n^o 1 (28 mars 2020) : 42–47. http://dx.doi.org/10.22314/2658-4859-2020-67-1-42-47.

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In power transformers, energy losses in the form of heat are about 2 percent of their rated power, and in transformers of large power centers reach hundreds of kilowatts. Heat is dissipated into the environment and heats the street air. Therefore, there is a need to consume this thermal energy as a source of heat supply to nearby facilities. (Research purpose) To develop methods and means of using excess heat of power transformers with improvement of their cooling system design. (Materials and methods) The authors applied following methods: analysis, synthesis, comparison, monographic, mathematical and others. They analyzed various methods for consuming excess heat from power transformers. They identified suitable heat supply sources among power transformers and potential heat consumers. The authors studied the reasons for the formation of excess heat in power transformers and found ways to conserve this heat to increase the efficiency of its selection. (Results and discussion) The authors developed an improved power transformer cooling system design to combine the functions of voltage transformation and electric heating. They conducted experiments to verify the effectiveness of decisions made. A feasibility study was carried out on the implementation of the developed system using the example of the TMG-1000/10/0.4 power transformer. (Conclusions) The authors got a new way to use the excess heat of power transformers to heat the AIC facilities. It was determined that the improved design of the power transformer and its cooling system using the developed solutions made it possible to maximize the amount of heat taken off without quality loss of voltage transformation.

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Melnikova, O. S., et V. S. Kuznetsov. « Method of calculating the electric strength of oil channels of the main insulation of power transformers ». Vestnik IGEU, n^o 5 (30 décembre 2020) : 48–55. http://dx.doi.org/10.17588/2072-2672.2020.5.048-055.

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The most damage-sensitive unit of power transformers is the main insulation of the oil barrier type. The breakdown of such insulation occurs as a result of the breakdown of the oil channel near the high voltage winding. In accordance with traditional methods of calculating the dielectric strength of insulation, the value of the breakdown strength is determined by empirical formulas depending on the selected width of the oil channel. The existing methods do not consider the influence of the oil channel volume, of the electric strength the statistical characteristics of the oil, the design features of the insulation of power transformers, and do not contain recommendations for creating design models. Thus, to improve the calculation accuracy, it is relevant to develop the evaluation method of dielectric strength of the main insulation of power transformers taking into account the volume and parameters of the breakdown voltage distribution of transformer oil, design features. The research results of the breakdown tension in oil channels with different volumes of transformer oil were used. To improve the accuracy of the calculation and taking into account the design features, the model of the main insulation of power transformers was made in the ANSYS program. Boundary data and assumption of linear stress distribution of transformer coils were considered. A method for calculating the dielectric strength of oil channels of the main insulation of power transformers, considering the volume and parameters of the breakdown voltage distribution of transformer oil was proposed. Unlike the existing methods, when calculating the minimum breakdown strength in the model of the main insulation, the design features of power transformers are taken into account and assumptions are justified to improve the accuracy of the calculation. In accordance with the methodology, the parameters of the dielectric strength of the transformer oil in the oil channel of the high voltage winding of the transformer were calculated. It was concluded that with increase of relative value of breakdown tension, dielectric strength of oil channel is decreasing, and it corresponds to physical sense of breakdown. The method for calculating the dielectric strength of transformer oil can be used when choosing the main insulation of power transformers in design.

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Ayvaz, Emrah, Tuba Buğdaycı Avşar, Mutlu Bektaş, Oğuz Kaan Atar, Büşra Büyükbaş, Celal Fadıl Kumru, Selçuk Çömlekçi, Mustafa Uğur Toruner, Bilal Bağcı et Mustafa Unver. « Increasing Efficiency by Applying a New Generation Dual-Core Transformer Design ». European Journal of Research and Development 2, n^o 4 (31 décembre 2022) : 203–12. http://dx.doi.org/10.56038/ejrnd.v2i4.121.

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In this study, in order to reduce the core losses of power transformers, the case of using two cores that can be activated according to the need instead of a single core is discussed. As it is known, in power transformers, the tolerance of core losses in the case of drawing the nominal power from the secondary depends on the materials used. In particular, the flux loss of the soft, siliceous sheet forming the core is tried to be improved by the manufacturing companies. However, if a small amount of the nominal power is drawn from this transformer while using a single core, core losses can be even greater than the power drawn. In the project of this study, a transformer with two different cores will be produced by dividing the core that will provide the total nominal power while manufacturing the transformer instead of a single core. Theoretical studies and simulation results show that this is possible. In the scientific literature, this situation is examined as a parallel study. It is known that transformers that show high variability in the amount of loading throughout the year in the national grid operate at a low occupancy rate. Instead of the single active core, the increase in the occupancy rate will make the second core active and meet the demand by working in parallel with the cores, which will contribute to the country's economy. Here, the switching on and off of the two cores placed in the same tank will be adapted considering the operating range of the cores with the highest efficiency by selecting the true direction of windings. Transformer prototypes to be produced within the scope of the new generation dual-core transformer project will be selected from among transformers with unbalanced load profiles in YEDAŞ responsibility areas, and transformers with a power of 2x50 kVA will be installed to be applied in pilot areas.

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Shen, Zhan, Bingxin Xu, Chenglei Liu, Cungang Hu, Bi Liu, Zhike Xu, Long Jin et Wu Chen. « The Modeling and Simplification of a Thermal Model of a Planar Transformer Based on Internal Power Loss ». Sustainability 14, n^o 19 (21 septembre 2022) : 11915. http://dx.doi.org/10.3390/su141911915.

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With the development of high-performance wide-band-gap devices and increasing converter frequency, planar transformers are widely used in high-frequency and high-power-density power conversions. Due to the skin effect and proximity effect, accurate thermal analysis and a simplified thermal model of planar transformers are needed for quick thermal verification as well as system design. This paper proposes two thermal simplification models based on the planar transformer’s thermal impedance network. The internal power loss and thermal coupling between each component are first analyzed. Then, based on thermal radiation theory, the simplified thermal model of the planar transformer is presented. It only requires the input of the total power loss of the planar transformer to calculate the temperature rise, and it does not need the power loss of each component. Finally, the simulation and experimental verification are carried out on a MHz prototype.

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Sharma, R. Rajesh. « Design of Distribution Transformer Health Management System using IoT Sensors ». September 2021 3, n^o 3 (16 septembre 2021) : 192–204. http://dx.doi.org/10.36548/jscp.2021.3.005.

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Transformers are one of the primary device required for an AC (Alternating Current) distribution system which works on the principle of mutual induction without any rotating parts. There are two types of transformers are utilized in the distribution systems namely step up transformer and step down transformer. The step up transformers are need to be placed at some regular distances for reducing the line losses happening over the electrical transmission systems. Similarly the step down transformers are placed near to the destinations for regulating the electricity power for the commercial usage. Certain regular check-ups are must for a distribution transformer for increasing its operational life time. The proposed work is designed to regularize such health check-ups using IoT sensors for making a centralized remote monitoring system.

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Nogueira, Teresa, José Carvalho et José Magano. « Eco-Friendly Ester Fluid for Power Transformers versus Mineral Oil : Design Considerations ». Energies 15, n^o 15 (27 juillet 2022) : 5418. http://dx.doi.org/10.3390/en15155418.

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Mineral oil has long been used as an adequate coolant and dielectric medium in power transformer design. However, it is flammable and environmentally risky as it may be leaked or spilled. Therefore, ester fluids, which have been increasingly used in the last two decades, look promising as an ideal dielectric option. This research aims to better understand how using ester fluid insulation in power transformers impacts their physical and electrical dimensions, including their load-losses, impedance, masses, and equipment dimensions. Three case studies were carried out in a Portuguese electrical equipment manufacturer’s facility, with varying electrical parameters and physical properties of the mineral oil and ester-filled power transformers. The main results enhanced the known good electrical behavior of ester fluids, namely creating a lower electric field around winding wedges, yet the use of ester fluids led to higher load-losses, larger masses, additional radiators and, consequently, higher manufacturing costs. Nevertheless, the contribution of ester-filled power transformers to the improved environmental safety (reducing spillage and fire risks), among other advantages, makes ester fluids a truly eco-friendly option for power transformer design.

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Snit’ko, I. S., A. I. Tikhonov, A. V. Stulov et V. E. Mizonov. « Development of model of transient modes taking into account mutual inductance of scattering fields for implementation of digital twin of transformer ». Vestnik IGEU, n^o 4 (31 août 2021) : 47–56. http://dx.doi.org/10.17588/2072-2672.2021.4.047-056.

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Development of the refined mathematical models of power transformers (digital twins), which make it possible to calculate arbitrary modes of operation of these devices with high accuracy and increased speed is an urgent task. Currently, such problems are solved using simulation packages such as MatLab Simulink. One of the disadvantages of the existing simulation models of the transformer is the assumption that own leakage inductance of the windings is used. This assumption is not always acceptable. Thus, the purpose of this article is to develop models of transformers using matrices of mutual inductance of the scattering field. The finite element method is used to calculate the magnetic field in a 2D formulation, implemented by means of the EMLib library, as well as simulation methods with the MatLab Simulink package are applied. The authors have estimated the features and basic assumptions while developing refined mathematical models of power transformers of various designs (two- and three-winding). It makes possible to ensure the required accuracy when simulating transient and emergency modes of transformer operation. Field models have been developed to determine the own and mutual scattering inductance matrices. Simulation models of transformers of various designs with the use of winding leakage inductance matrices have been developed. The results of simulation of dynamic processes in a transformer in various modes are presented. Comparison of the results of the operation of models with matrices of mutual inductances and without them is carried out. The results of the research can be used during the design of power transformers in design companies and in production environment. It is also possible to use the developed models during operation of power transformers for the analysis of static and dynamic modes of operation of sections of electrical networks.

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Shabanov, Vitalii, Albina Rakhimberdina et Ilya Yanikiev. « ON THE ISSUE OF DETERMINING THE ELECTRICAL LOADS OF TRANSFORMER SUBSTATIONS ». Electrical and data processing facilities and systems 18, n^o 1 (2022) : 114–22. http://dx.doi.org/10.17122/1999-5458-2022-18-1-114-122.

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Relevance The calculation of electrical loads is the basis for choosing the carrying capacity of all elements of the electrical network. An increase in rated loads compared to the necessary ones leads to cost overruns on power transmission lines and an increase in power of transformers, and a decrease in rated loads leads to increased power dissipation in networks, increased heating of conductors and transformers and increased thermal deterioration of their insulation. The reliability of the calculation of electrical loads depends both on the reliability of the calculation coefficients used and on the correctness of the methods used. Therefore, the research and improvement of the calculation of electrical loads in the design of power supply systems is an actual problem. Aim of research To investigate the determination of rated loads of transformer substations, methods of accounting for power dissipation in different modes of operation of the power supply system and methods for determining rated currents of cable lines to transformer substations. To consider the correctness of the use of standard forms for determining electrical loads recommended by regulatory documents. To develop a generalized form of performing calculations of electrical loads of transformer substations, combining the calculation of loads on the side of lower and higher voltages. Research methods To solve the tasks, the definition of electrical loads according to standard forms of regulatory documents is investigated. The methods of accounting for power dissipation in transformers under different operating modes of the power supply system and the determination of rated currents along cable lines to transformer substations are considered. Results The shortcomings of the execution and design of the calculation of electrical loads according to standard forms are revealed: standard forms do not contain information at which values of the heating time constant calculations are performed to determine the rated power of the electrical power load on the side of the lower and higher voltages of transformer substations, do not contain the definition of power dissipation in transformers. Ways of improving the calculation of electrical loads of transformer substations are proposed. A generalized form of execution and design of calculations of electrical loads of transformer substations have been developed, which include the values of time constants when calculating electrical power loads, the type and passport data of the selected transformer, calculations of power dissipation in transformers in two modes and calculations of the load current of cable lines to transformer substations.

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Chernov, Y. A., N. Yu Dmitrieva et O. Yu Kokorina. « POWER SUPPLY SYSTEM WITH THREE-PHASE TRANSFORMERS FOR HSR ». World of Transport and Transportation 15, n^o 1 (28 février 2017) : 48–62. http://dx.doi.org/10.30932/1992-3252-2017-15-1-5.

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[For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version)].ABSTRACT The article presents a schematic diagram of a traction substation of the 2x25 kV power supply system with three-phase transformers and a vector voltage diagram for high-speed lines. Power supply systems 2x25 kV with single-phase and three-phase transformers are compared, the power of three-phase transformers for high-speed main lines is recommended. And all this taking into account the new special technical conditions that are worked out for the design, construction and operation of Russian HSR. Keywords: railway, high-speed railway, traction substation, 2x25 kV power supply system, three-phase transformer, single-phase transformer, special technical conditions.

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Seheda, M. S., P. F. Gogolyuk et Y. V. Blyznak. « High-frequency periodic processes in two-winding power transformers ». Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, n^o 6 (2021) : 96–100. http://dx.doi.org/10.33271/nvngu/2021-6/096.

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Purpose. Mathematical modeling of high-frequency periodic processes in winding power transformers to improve the technology of their design and operation. Methodology. The methods of the formation of mathematical models for the research of high-frequency periodic processes in transformers and methods of solving systems of partial differential equations are applied. Findings. The mathematical model for the research of high-frequency periodic processes in two-winding transformers, with adequate considering of electromagnetic connections of windings and structural parameters of transformers, is created. Originality. To form a mathematical model for the research of high-frequency periodic processes, a substitute scheme of a two-windings transformer, taking into account the parameters of the electric and magnetic circuits of windings and electromagnetic connections between them, is proposed. Practical value. The mathematical model, which allows analyzing the voltage distribution in the transformer windings for high-frequency periodic processes in windings, and adjusting their insulating abilities, is created.

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Snyder, Harold L. « High Temperature Isolated Switch Mode Power Supply with Integrated Power and Feedback Transformer ». Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2014, HITEC (1 janvier 2014) : 000214–17. http://dx.doi.org/10.4071/hitec-wp13.

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High temperature switch mode power supplies (SMPS) typically utilize magnetic solutions such as low permeability transformers for isolation from ground loops. However, imposed design constraints almost always restrict the size of switch mode power supply systems to less than the minimum space necessary for a good design, resulting in only adequate and sometimes unreliable switch mode power supply designs. Integrating the control loop and magnetic system functions is implemented by taking advantage of the bi-directional characteristics of transformers, which allows the designer an opportunity to further minimize the design space by eliminating unnecessary loop components. This is a prudent step prior to the construction of high temperature hybrids and multichip modules. Combining the operation of both the control loop and the magnetic transformer allows the designer to reduce the size of the design, regain the ability to provide a good design in the volume allotted, while still maintaining loop stability. The design procedure for this integrated control loop and magnetics system is examined, and an example circuit is simulated in SPICE with a Jiles-Atherton hysteresis model, and the circuit is realized through construction and measurements which are presented for a single forward based design targeted for operation at high temperatures.

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Orosz, Tamás, Bence Borbély et Zoltán Ádám Tamus. « Performance Comparison of Multi Design Method and Meta-Heuristic Methods for Optimal Preliminary Design of Core-Form Power Transformers ». Periodica Polytechnica Electrical Engineering and Computer Science 61, n^o 1 (10 février 2017) : 69–76. http://dx.doi.org/10.3311/ppee.10207.

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Large power transformers are regarded as crucial and expensive assets in power systems. Due to the competing global market, to make a good and competing power transformer design, a non-linear optimization problem should be solved in a very short time in the preliminary design stage. The paper shows and compares the performance of four different methods to solve this problem for three phase core type power transformers. The first algorithm is a novel meta-heuristic technique which combines the geometric programming with the method of branch and bound. Then this conventional multi design method is solved by a simple iterative technique and two novel evolutionary algorithms to enhance the convergence speed. One of these algorithms is the particle swarm optimization technique which is used by many other researchers and the grey wolf optimization algorithm which is a new method in this optimization sub-problem. An example design on an 80 MVA, three phase core type power transformer using these four methods is presented and its performances are analyzed. The results demonstrate that the grey wolf optimization is a good alternative for this optimization problem.

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Tikhonov, A. I., A. V. Stulov, I. S. Snitko et A. V. Podobnyj. « Development of 2D models of the magnetic field for digital twin technology and generative design of power transformers ». Vestnik IGEU, n^o 3 (30 juin 2020) : 32–43. http://dx.doi.org/10.17588/2072-2672.2020.3.032-043.

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The development of generative design technologies that solve the problems of structural optimization and digital twins, that is simulation models of devices with at least 95 % accuracy, is an urgent task. These tech-nologies are usually implemented on the basis of 3D models of physical fields, for example, using ANSYS Maxwell or COMSOL Multiphysics packages, which are demanding in terms of computer resources and de-signer skills. However, the sufficient accuracy for transformer digital twins can be achieved using chain and 2D field models. The article aims to develop the models to calculate the transformer with the accuracy and ability to take into account the design features of a particular device, which is characteristic of digital twins. This can be used in generative design of transformers and in the study of their operation modes. The finite element method implemented via the authoring EMLib library which allows calculating magnetic fields in a 2D formulation was used. The simulation methods using the MatLab Simulink SymPowerSystem package were also employed. The assumptions made during the power transformer simulation have been estimated. They include the possibility of using chain and 2D field models without taking into account the steel anisotropy with Dirichlet boundary conditions when calculating the scattering fluxes. 2D field models have been developed for calculating the main flux and scattering fluxes, which are able to form the basis for digital twin technology and generative design of transformers. A simulation model of a transformer implemented in MatLab Simulink has been provided. The possibility of using the models for diagnosing transformer faults has been demonstrated. The simulation results of a transformer with a defect have been presented. The results obtained can be used in the development of transformers to search for optimal designs and to study the results of design decisions without creating prototypes. The findings can also be applied while operating the transformers to assess the damage and failures without dismantling and according to the test results.

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Jain, Akansha, et Masoud Karimi-Ghartemani. « Mitigating Adverse Impacts of Increased Electric Vehicle Charging on Distribution Transformers ». Energies 15, n^o 23 (29 novembre 2022) : 9023. http://dx.doi.org/10.3390/en15239023.

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As the world is transitioning to electric vehicles (EVs), the existing power grids are facing several challenges. In particular, the additional charging power demand may repeatedly overload the traditionally-sized distribution transformers and adversely impact their operational life. To address this challenge, this paper proposes an EV-based reactive power compensation strategy for transformer overloading mitigation. Specifically, a low-bandwidth centralized recursive controller is proposed to determine a set point for the EV’s onboard charger’s reactive power. Importantly, the proposed strategy is practically implementable in existing distribution grids as it does not rely on smart grid infrastructure and is stable under potential communication delays and partial failures. This paper discusses the controller’s structure, design, and stability in detail. The proposed solution is tested with a realistic secondary distribution system considering four different EV charging scenarios with both Level 1 and Level 2 residential EV charging. Specifically, IEEE Standard C57.91-2011 is used to quantify the impact of EV charging on the transformer’s life. It is shown that with the proposed method, transformer overloading is significantly reduced, and the transformer’s life improves by an average of 47% over a year in all four scenarios.

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Lin, Jing-Yuan, Hsuan-Yu Yueh, Yi-Feng Lin et Pin-Hsien Liu. « Analysis and Design of Three-Phase LLC Resonant Converter with Matrix Transformers ». Energies 15, n^o 4 (11 février 2022) : 1315. http://dx.doi.org/10.3390/en15041315.

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This study presents the topology of a three-phase LLC resonant converter with matrix transformers. The three-phase LLC resonant converter has the advantages of conventional LLC resonant converters, including zero-voltage switching at the primary side, zero-current switching at the secondary side, high-frequency feasibility, and high efficiency. Moreover, it has additional advantages that differ from conventional LLC, including low output capacitor current ripple, natural current sharing in three resonant currents, and a high power level. As a result of the above mentioned characteristics, LLC topology has been used in many electric vehicle charging systems, server power systems, and other high-power applications. However, as the power level becomes higher and higher, the input voltage is usually too high to reduce conduction loss, and the output current also increases. This situation makes transformer design more difficult. The increasing current means more core and copper loss, and the heat dissipation of the transformer becomes more difficult. Matrix transformer technology can improve this problem directly and simply. By utilizing matrix transformers, which are primary series connected and secondary parallel connected, the primary voltage stress and secondary current stress of the transformers can be reduced, and the output current can be distributed. The analysis of the proposed converter in this study includes a circuit operation introduction, a time-domain analysis, calculation of the transfer ratio curve in the frequency domain, and a loss analysis. The theoretical analysis and performance of the proposed converter are verified. A three-phase LLC resonant converter with matrix transformers prototype is built with a high input voltage of 800-VDC and high output current of 200-A. The output voltage is 100-VDC. The waveform and efficiency data will be shown in the experimental results.

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Garrett, J. H., et A. Jain. « Encore : an object-oriented knowledge-based system for transformer design ». Artificial Intelligence for Engineering Design, Analysis and Manufacturing 2, n^o 2 (mai 1988) : 123–34. http://dx.doi.org/10.1017/s0890060400000603.

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The design of electronic power transformers is an activity that requires the application of well-established algorithms from electromagnetic theory and heuristic, judgmental techniques derived from experience in the design and manufacturing of these devices. This paper describes an object-oriented knowledge-based system, Encore, that was developed at Houston Downhole Sensors (a division of Schlumberger Well Services). Encore combines object-oriented, rule-based, and procedural programming techniques to design 60 Hz power transformers. The system uses a heuristic search strategy to generate design alternatives, and then selects the “best” design based on size and efficiency considerations The heuristics are represented and applied as rules; the electromagnetic components are modelled as frame-like objects. The object-oriented nature of this system facilitated enhancements; by specializing some of the objects comprising a power transformer, a power inductor model was quickly developed. Encore reduces design time from a couple of days to less than an hour; it is being used to design the transformers and inductors of power supplies in new Schlumberger well-logging tools. The system was implemented on a Xerox interlisp Workstation using an object-oriented environment called STROBE.

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Chang, Wen-Ching, et Cheng-Chien Kuo. « A Novel Excitation Approach for Power Transformer Simulation Based on Finite Element Analysis ». Applied Sciences 11, n^o 21 (3 novembre 2021) : 10334. http://dx.doi.org/10.3390/app112110334.

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Power transformers play an indispensable component in AC transmission systems. If the operating condition of a power transformer can be accurately predicted before the equipment is operated, it will help transformer manufacturers to design optimized power transformers. In the optimal design of the power transformer, the design value of the magnetic flux density in the core is important, and it affects the efficiency, cost, and life cycle. Therefore, this paper uses the software of ANSYS Maxwell to solve the instantaneous magnetic flux density distribution, core loss distribution, and total iron loss of the iron core based on the finite element method in the time domain. In addition, a new external excitation equation is proposed. The new external excitation equation can improve the accuracy of the simulation results and reduce the simulation time. Finally, the three-phase five-limb transformer is developed, and actually measures the local magnetic flux density and total core loss to verify the feasibility of the proposed finite element method of model and simulation parameters.

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Orosz, Tamás, David Pánek et Pavel Karban. « FEM Based Preliminary Design Optimization in Case of Large Power Transformers ». Applied Sciences 10, n^o 4 (17 février 2020) : 1361. http://dx.doi.org/10.3390/app10041361.

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Since large power transformers are custom-made, and their design process is a labor-intensive task, their design process is split into different parts. In tendering, the price calculation is based on the preliminary design of the transformer. Due to the complexity of this task, it belongs to the most general branch of discrete, non-linear mathematical optimization problems. Most of the published algorithms are using a copper filling factor based winding model to calculate the main dimensions of the transformer during this first, preliminary design step. Therefore, these cost optimization methods are not considering the detailed winding layout and the conductor dimensions. However, the knowledge of the exact conductor dimensions is essential to calculate the thermal behaviour of the windings and make a more accurate stray loss calculation. The paper presents a novel, evolutionary algorithm-based transformer optimization method which can determine the optimal conductor shape for the windings during this examined preliminary design stage. The accuracy of the presented FEM method was tested on an existing transformer design. Then the results of the proposed optimization method have been compared with a validated transformer design optimization algorithm.

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Wang, Bingting, Ziping Cao, Zhen Luan et Bo Zhou. « Design and Evaluation of Band-Pass Matching Coupler for Narrow-Band DC Power Line Communications ». Journal of Circuits, Systems and Computers 28, n^o 07 (27 juin 2019) : 1950119. http://dx.doi.org/10.1142/s0218126619501196.

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In power line communication (PLC), coupling transformers are usually required for coupling, band-pass filtering and impedance matching. However, coupling transformer design involves so many parameters that it is typically an imprecise and experimental procedure. In addition, the cost and size of transformers prevent them from being an economic and compact solution for PLC couplers. This paper first analyzes a simplified, distributed parameter model of the power line, which can be used to calculate power line impedance easily and accurately. Next, a low-cost, band-pass matching coupler with compact architecture is designed to replace the coupling transformer for direct current PLC (DC-PLC), which ensures impedance matching on the basis of an accurate power line impedance instead of using an average value. Finally, simulations as well as laboratory tests are conducted under 95–125[Formula: see text]kHz (CENELEC B-band), which confirm the new coupler’s excellent band-pass filtering and impedance matching performance.

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V Swathi, G., N. Paparao et D. Swathi. « Design an Efficient Power Electronics Transformer (PET) for the Improvement of Quality in Power ». International Journal of Engineering & ; Technology 7, n^o 3.12 (20 juillet 2018) : 1046. http://dx.doi.org/10.14419/ijet.v7i3.12.17629.

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This paper consists of a new device called as Power Electronics transformer (PET) which has been recommended in paper so that it understands that voltage transformation, galvanic isolation, and enhancing force personal satisfaction for a just gadget. The PET gives a complete methodology for designing a transformer that uses Power electronic frameworks which comprises for primary coil and auxiliary coils of a transformer. A couple features to example, such-and fast voltage regulation, voltage list recompense what's more likewise revision for control figure could a chance to be united under PET. This paper indicates another thought of plotting An vitality electronic transformer. In the schema process, those AC/DC, DC/AC, AC/AC converters In addition secondary back transformers have been utilized. Grid converter similarly meets desires Likewise AC/AC converter on force electronic transformer. Those proposed drive electronic transformer performs perplexedly capacities to example, amendment regarding energy. Factors, elimination of swell and voltage sag, reduction of voltage flicker and fault situation protection capabilities. The recommended force electronic transformer need been shown using MATLAB/ SIMULINK Furthermore also change Previously, force characteristic with recommended perfect gas need been checked by the simulink outcomes.

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Kim, Jinwook, Do-Hyeon Kim, Jieun Kim et Young-Jin Park. « Wireless Power Transfer between Two Self-Resonant Coils over Medium Distance Supporting Optimal Impedance Matching Using Ferrite Core Transformers ». Energies 14, n^o 24 (17 décembre 2021) : 8540. http://dx.doi.org/10.3390/en14248540.

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An efficient wireless power transfer (WPT) system is proposed using two self-resonant coils with a high-quality factor (Q-factor) over medium distance via an adaptive impedance matching network using ferrite core transformers. An equivalent circuit of the proposed WPT system is presented, and the system is analyzed based on circuit theory. The design and characterization methods for the transformer are also provided. Using the equivalent circuit, the appropriate relation between turn ratio and optimal impedance matching conditions for maximum power transfer efficiency is derived. The optimal impedance matching conditions for maximum power transfer efficiency according to distance are satisfied simply by changing the turn ratio of the transformers. The proposed WPT system maintains effective power transfer efficiency with little Q-factor degradation because of the ferrite core transformer. The proposed system is verified through experiments at 257 kHz. Two WPT systems with coupling efficiencies higher than 50% at 1 m are made. One uses transformers at both Tx and Rx; the other uses a transformer at Tx only while a low-loss coupling coil is applied at Rx. Using the system with transformers at both Tx and Rx, a wireless power transfer of 100 watts (100-watt light bulb) is achieved.

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Papaika, Yu A., I. M. Lutsenko, IE V. Koshelenko et P. S. Tsyhan. « Methodology for selecting the rated parameters of power transformers in the town’s electrical distribution networks in settlements ». Electrical Engineering and Power Engineering, n^o 2 (30 juin 2021) : 33–43. http://dx.doi.org/10.15588/1607-6761-2021-2-4.

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Purpose. To substantiate a technique of a choice of nominal power of power transformers for increase of their use efficiency in distributive electric networks of the cities Methods. Analytical processing of statistical data. Findings. The paper solves the problem of efficient use of the installed power of transformers, their rational choice in the design of urban electrical networks. It was found that the choice of transformers according to classical methods causes a significant error and an overestimation of the rated power at the design stage. The method of reducing this error was developed for selecting the power of transformers of urban electrical networks. This method takes into account the predicted indicators of the operating modes of the equipment, the type of consumers, the load capacity of the equipment, the parameters of the operating mode and the environment, constant heating time of existing types of transformers that can be accepted for installation, the appropriate level of reactive load compensation. Originality The scientific novelty lies in the development of the method for selecting the rated power of power transformers 6 (20) /0.4 kV urban distribution networks by comprehensive consideration of the parameters of typical consumers and their actual structure, which will effectively use transformer equipment for load capacity during the regulated period of their operation. Practical value. The obtained results show the increase in the efficiency of capital and operating costs by selecting a rational rated power of distribution transformers 6 (20) / 0.4 kV with ensuring the effective use of their load capacity in the conditions of electric grids of cities.

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LARIN, Vasily S., et Daniil A. MATVEEV. « Approximation of Transient Resonance Voltages and Currents in Power Transformer Windings to Determine Their Natural Frequencies and Damping Factors ». Elektrichestvo 12, n^o 12 (2020) : 44–54. http://dx.doi.org/10.24160/0013-5380-2020-12-44-54.

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Transient interaction between power transformers and power cable lines may give rise to resonance overvoltages in the transformer primary windings. To develop protection measures against resonance overvoltages and to design transformers resistant to resonance overvoltages, it is necessary to know the natural frequencies of the transformer windings. Recent years have seen very rapid development of transformer windings high-frequency models. However, the mathematical models used in practice, which came from calculations of impulse overvoltages in transformer windings, reproduce the frequency dependences of losses and damping at natural frequencies with insufficient accuracy. To verify and improve the mathematical models used for analyzing high-frequency processes in transformer windings, it is necessary to have sufficient experimental data on the values of natural frequencies and damping factors. Methods for experimentally determining the natural frequencies and damping factors of power transformer windings are considered. Theoretical principles and analytical expressions for transient voltages and currents obtained for simplified equivalent circuits of windings with lumped parameters are given. An approach is proposed, according to which the transient voltages and currents in the winding are represented as the sum of steady-state and free components. The free component is then approximated using the theoretical expressions obtained for the equivalent circuits of the windings. The results of applying the approach to approximating the transient voltage at the midpoint and the current in the neutral of a dry-type transformer’s high-voltage winding are presented.

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Wu, Gang, et Yu Tang. « Design of Switch Transformer about the Push-Pull Switch Power Supply ». Applied Mechanics and Materials 341-342 (juillet 2013) : 1266–70. http://dx.doi.org/10.4028/www.scientific.net/amm.341-342.1266.

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the push-pull switch power is a kind of form in the family. It has the characteristics of good voltage output, high efficiency, the simple circuit and so on. On the design of the push-pull switch power supply, the key and difficult point is the design of switch transformer. Taking the switch transformer of a push-pull switching power supply as the research object and based on the design requirements, this paper aims to realize the calculation of the coil turns in switching transformer. Meanwhile, under the consideration of the skin effect and the proximity effect and the choices of switch transformers wires and the methods of wires winding, the design of switch transformer of the push-pull switch power supply has been completed by circuit simulation and implementation.

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Lesniewska, Elzbieta. « Influence of the Selection of the Core Shape and Winding Arrangement on the Accuracy of Current Transformers with Through-Going Primary Cable ». Energies 14, n^o 7 (31 mars 2021) : 1932. http://dx.doi.org/10.3390/en14071932.

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The current transformers with split-core are used for installation in places where it is impossible to install classic current transformers. Moreover, this design allows for any measurement location change, and even switching one current transformer into several different shapes of bars or cables. Power network operators, striving for more accurate current measurements, require producers to provide current transformers with a special accuracy class 0.2S. Therefore, manufacturers and designers try to meet the market requirements and, similarly to non-demountable current transformers, i.e., with a toroidal core, design current transformers with split-core class 0.2S. To meet the high metrological requirements, 3D analyses of electromagnetic fields were performed, taking into account physical phenomena and not approximate analytical models. Two types of cores and four different arrangements of the secondary windings of the measuring current transformers were considered. The magnetic field distributions, current error, and phase displacement diagrams of all current transformer models were analyzed, and the model of the transformer structure with the best accuracy was selected. Computations were conducted based on the finite element numerical method, and the results were compared with the real model tests.

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Li, Yinan, Rui Wang, Liping Zhong, Limin Mao, Chuan Sun, Xiaodong Li et Song Hu. « Analysis and Design of a High-Frequency Isolated Dual-Transformer DC-DC Resonant Converter ». Electronics 12, n^o 1 (27 décembre 2022) : 103. http://dx.doi.org/10.3390/electronics12010103.

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This paper presents the operation, analysis, design, simulation, and experimental results for a proposed Dual-Transformer DC-DC Resonant Converter (DTRC). A three-arm bridge is employed on the input side and an H-type bridge is employed on the output side of the DTRC, and the two bridges are connected with two high-frequency (HF) transformers. By optimizing the ratio k of the two HF transformers, the proposed DTRC has a lower boundary power for losing zero-voltage switching (ZVS). That means the DTRC has a wider ZVS operation range and lower switching loss when compared with a traditional soft-switching pulse width modulation (PWM) resonant converter. The operation principle, power transfer, ZVS characteristics, and design procedures are analyzed in detail. Both simulation and experimental results prove the feasibility and superiority of the proposed Dual-Transformer DC-DC Resonant Converter.

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Jarrahi, Mohammad Amin, Emad Roshandel, Mehdi Allahbakhshi et Mohammad Ahmadi. « Cost-optimal as a tool for helping in designing distribution transformer using particle swarm optimization ». COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 38, n^o 2 (4 mars 2019) : 862–77. http://dx.doi.org/10.1108/compel-06-2017-0229.

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Purpose This paper aims to achieve an optimal design for distribution transformers considering cost and power losses. Particle swarm optimization (PSO) algorithm is used as an optimization tool for minimizing the objective functions of design procedure which are cost and electrical and iron losses. Design/methodology/approach In this paper, distribution transformer losses are considered as operating costs. Also, transformer construction cost which depends on the amount of iron and copper in the structure is assumed as its initial cost. In addition, some other important constraints such as appropriate ranges of transformer efficiency, voltage regulation, temperature rise, no-load current, and winding fill factor are investigated in the design procedure. The PSO algorithm is applied to find optimum amount of needed copper and iron for a typical distribution transformer. Moreover, transformer impedance considered as a constraint to achieve an acceptable voltage regulation in the design process. Findings It is shown that the proposed design procedure provides a simple and effective approach to estimate the flux and current densities for minimizing the active part cost and active power losses which means reduction in amount of transformer total owning cost (TOC). Originality/value The methodology advances a proposal for reducing distribution transformers costs using PSO algorithm. The approach considers the aforementioned constraints and TOC to minimize the active part cost and maximize the efficiency. It is demonstrated that a designed transformer will not be optimum when the transformer losses over years are not considered in design procedure. Finally, the results prove the effectiveness of the proposed procedure in designing cost-effective distribution transformers from its initial cost until its whole life.

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Orjiewulu, J. C., D. C. Chukwuemeka, C. E. Jesusblessing et A. Ibrahim. « DESIGN AND IMPLEMENTATION OF AN AUTO-TEMP CONTROL SYSTEM FOR DISTRIBUTION TRANSFORMER ». Open Journal of Engineering Science (ISSN : 2734-2115) 1, n^o 2 (9 septembre 2020) : 1–19. http://dx.doi.org/10.52417/ojes.v1i2.142.

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Unreliability and interruptions facing power supply are evidence of the excessive heat generated in power systems, as a result of the inefficiency of oil cooling medium employed in distribution transformers. The design and implementation of a prototype automatic temperature control system is to be employed as a method towards solving the above stated problem of excessive temperature rise in distribution transformers. The prototype design consists of a PIC microcontroller programmed in C language, an LM35 temperature sensor, an electric fan and other diverse electronic component. It operates a mechanism that detects temperature rise in the transformer and automatically turns on the cooling fan at extreme temperature conditions. A 16x2 LCD is employed as the medium for temperature display unit of the transformer. The resulting prototype functions in a way that it has the ability to detect every 1ºC rise and reduction in the temperature of the transformer. Thus, at extreme temperature conditions, the automatic temperature control system diminishes the excessive heat generated in the transformer to the appropriate working temperature condition. Orjiewulu, J. C. | Department of Electrical Electronics Engineering, University of Benin, Benin City, Edo State, Nigeria.

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Changjiang, Zheng, Wang Qian, Wang Huai, Shen Zhan et Claus Leth Bak. « Electrical Stress on the Medium Voltage Medium Frequency Transformer ». Energies 14, n^o 16 (19 août 2021) : 5136. http://dx.doi.org/10.3390/en14165136.

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This paper proposes an equivalent circuit model to obtain the transient electrical stress quantitatively in medium voltage medium frequency transformers in modern power electronics. To verify this model, transient simulation is performed on a 1.5 kV/1 kHz transformer, revealing voltage overshoot quantitatively between turns and layers of the transformer’s HV winding. Effects of rise time of the input pulse voltage, stray capacitance of the winding insulation, and their interactions on the voltage overshot magnitude are presented. With these results, we propose limiting the voltage overshoot and, thereafter, enhancing medium voltage medium frequency transformer’s insulation capability, which throws light on the transformer’s insulation design. Additionally, guidance on the future studies on aging and endurance lifetime of the medium voltage medium frequency transformer’s insulation could be given.

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Wang, En Lu, Qing Hao Wang, Chuan Zong Zhao, Wen Guang Zhang, Yan Hai Huang, Chuan Bo Liu, Xiao Liu, Xiao Shu Zhang, Rui Tong et Hua Zhang. « Development and Application of Power Transformer Oil Purifier in Line ». Advanced Materials Research 986-987 (juillet 2014) : 1210–13. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.1210.

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Power transformer oil purifier described in this article is equipment that filters charged transformer oil in running transformers. Transformer oil can be filtered on line to improve performance of the transformer oil. This article analyzes the necessity of the purification and filtration on processing power transformer oil, describes the overall design ideas of oil purifier in line. Through examples, power transformer oil purifier in line is further discussed the steps and precautions in the application. By comparing the power outage transformer oil purifier and oil purifier in line, the superiority and science of oil purifier in line are clarified.

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Ataullah, Haris, Taosif Iqbal, Ihsan Ullah Khalil, Al-Sharef Mohammad, Nasim Ullah et Mohamed Emad Farrag. « Analysis and Verification of Leakage Inductance Calculation in DAB Converters Based on High-Frequency Toroidal Transformers under Different Design Scenarios ». Energies 15, n^o 17 (25 août 2022) : 6176. http://dx.doi.org/10.3390/en15176176.

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High-frequency transformers are becoming an essential component in the integration of power resources that rely on power electronic converters; their efficiency and performance are influenced by parasitic characteristics in the interface. In this article, the design of a high-frequency toroidal transformer has been explained in detail using the ANSYS Maxwell platform. Various parameters, such as leakage inductance, magnetic flux density, magnetic field strength and uniform magnetic flux line are analyzed using Finite element analysis. High-frequency transformers using a toroidal core with different winding configurations are examined and all parameters obtained through simulation are validated by an analytical approach. Analysis of each design is based on its leakage inductances, which will aid in the appropriate selection of transformers as a function of their operating frequency. This analysis is expected to guide designers to optimize the high-frequency transformer parameters based on practical applications. The optimized parameters are then applied for a dual active bridge (DAB) converter within MATLAB/Simulink to verify the design process. A prototype has been built to validate the simulation and design procedure. The results obtained from both simulation and experiments are compared and show great correlation.

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Ottele, Andy, et Rahmat Shoureshi. « Neural Network-Based Adaptive Monitoring System for Power Transformer ». Journal of Dynamic Systems, Measurement, and Control 123, n^o 3 (11 février 1999) : 512–17. http://dx.doi.org/10.1115/1.1387248.

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Power transformers are major elements of the electric power transmission and distribution infrastructure. Transformer failure has severe economical impacts from the utility industry and customers. This paper presents analysis, design, development, and experimental evaluation of a robust failure diagnostic technique. Hopfield neural networks are used to identify variations in physical parameters of the system in a systematic way, and adapt the transformer model based on the state of the system. In addition, the Hopfield network is used to design an observer which provides accurate estimates of the internal states of the transformer that can not be accessed or measured during operation. Analytical and experimental results of this adaptive observer for power transformer diagnostics are presented.

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Oyeleye, Yinka, Dare Adeniran et Emmanuel Itodo. « Design of Effective 33/11 kV Injection Substations Using International Standards ». Journal of Applied Science & ; Process Engineering 8, n^o 2 (31 octobre 2021) : 977–85. http://dx.doi.org/10.33736/jaspe.3625.2021.

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This research focuses on the design of an effective 33/11 kV modelled injection substation that conforms to an appropriate standard for equipment protection, the safety of personnel and power quality compliance. This is to provide a solution to one of the major problems industries in Nigeria faces due to sudden voltage fluctuations in the power system which results in damages to equipment and thus outage of power supply and damages to substation equipment. The methodology involved designing an effective 33/11 kV injection substation and associated distributive substation elements using international codes and applicable algorithms. 60% loading of transformer and additional 1.25 factor of future expansion (F.E) were considered too. The results showed that a 7.5 MVA injection transformer was designed to operate at 60%. Also, the results revealed that the injection substation would feed 15 numbers of 500 kVA distributive transformers. Each distribution substation was sized in accordance with the 7.5MVA injection transformer philosophy in this work. This research concludes that the injection substation must be loaded at 60% with an additional 1.25 F.E. in order to increase the transformer life span, and the 7.5MVA injection substation can crater for 15nos of 500 kVA distribution transformers in this research. Each substation will reliably and effectively carry the expected load demand. This research recommends that injection substations should be designed for areas with high energy requirements for reliable power quality. It recommends that substations should conform to 60% loading at the initial years of usage and that the substation design should conform to appropriate standards used in this work.

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Toscani, Nicola, Massimo Brunetti, Maria Stefania Carmeli, Francesco Castelli Dezza et Marco Mauri. « Design of a Rotary Transformer for Installations on Large Shafts ». Applied Sciences 12, n^o 6 (13 mars 2022) : 2932. http://dx.doi.org/10.3390/app12062932.

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Rotary transformers are adopted to transfer energy from primary to secondary in situations in which the two sides are in relative rotation. These devices are cylindrical transformers with two cores and the corresponding winding separated by an air gap. Their employment became quite convenient with the availability of power electronics, allowing the operation of electrical systems at relatively high frequencies. In particular, this paper proposes the design of a light and efficient transformer which can be used in applications involving large shafts. Moreover, a sliced arrangement for the magnetic core is proposed together with the experimental validation of this solution on a reduced-size prototype.

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Lesniewska, Elzbieta. « Modern Methods of Construction Problem Solving in Designing Various Types of Instrument Transformers ». Energies 15, n^o 21 (3 novembre 2022) : 8199. http://dx.doi.org/10.3390/en15218199.

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Current and voltage instrument transformers are essential elements of the power system. They work like transformers but do not transmit power. Their task is to accurately transform currents or voltages during system operation, which are then used for measurement and protection. These devices are very precise, and their accuracy is defined by the IEC/CEN standards. Instrument transformers are located at all transformer stations, specialized high-voltage and high-power laboratories, and testing and teaching laboratories. Therefore, the design requirements are very different depending on their type (current, voltage, or combined), function (measuring, protection), and operating voltage (high, medium, and low). The requirements concern not only the operation but also the strength of the insulation system and, sometimes, the mechanical strength.

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Robinson, Michael C., Sara E. Wallace, David C. Woodward et Gene Engstrom. « US Navy Power Transformer Sizing Requirements Using Probabilistic Analysis ». Journal of Ship Production 22, n^o 04 (1 novembre 2006) : 212–18. http://dx.doi.org/10.5957/jsp.2006.22.4.212.

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Sizing power transformers in US Navy ships is an issue that surfaced in the design of a new amphibious assault ship. Previous methods averaged the power output from generators over each transformer and calculated load based on a demand factor curve. This technique is not accurate enough in the contract design stages or for zonal architectures since it artificially averages the electrical loads. The proposed methodology uses a systems engineering approach, applying a probabilistic (Monte Carlo) analysis of the electrical loads at each transformer, based on the electrical load analysis (ELA). This methodology will allow the designer to incorporate risk mitigation into a radial or zonal electrical system design to verify adequacy and reduce cost through probability-based transformer sizing.

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Avdieieva, O. А., L. V. Vakhonina, O. S. Sadovoy, R. A. Stavinskiy et O. M. Tsyganov. « Improving the main indicators of transformers with twisted one-piece magnetic cores by changing the technology of circular winding turns formation ». Electrical Engineering & ; Electromechanics, n^o 3 (30 mai 2022) : 3–7. http://dx.doi.org/10.20998/2074-272x.2022.3.01.

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Introduction. With the adoption of standards to reduce losses in transformers it is necessary to change the design of transformers that remain unchanged. Further energy saving is possible with the use of non-traditional technical solutions for the improvement of transformers. Problem. In order to reduce idle losses, the curved magnetic circuits of power transformers are carried out in the form of low-volume circuits. Windings are injected into assembled magnetic conductors by shuttle machines. The shuttle of windings provides technological gaps in winding windows, which results in an increase in size, metal capacity and losses. Goal. Rationale for transformer performance improvement by excluding process gaps in winding windows. Methodology. The definition of the change in transformer indicators is performed using optimization functions of the dimensionless indicators of the technological level. The adequacy of the functions is confirmed by the calculation of the mass of the electromagnetic system and the losses of the transformer. The figures of the compact analogue are calculated from the named serial analogue. Results. The result is a reduction in mass and a loss in the compactness of the transformer. Originality. The improvement of the indicators and the simplification of the winding technology are provided by a change in the design of insulating frames of winding coils. Winding on the rods is ensured by rotating the outer part of the composite insulating frame. Practical significance. Replacement the design of the windings of transformer with power of 40 kVA of 1000 V voltage class with a spatially twisted, small-dimensional magnetic conductor on a compact analogue leads to a reduction in mass and overall dimensions by 15 % and (17-18) %. Efficiency increases by 0.3 %.

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Zhi, Weijie, YuWen Zhang et Hao Yang. « Electromagnetic Field Analysis and Optimization Method of High-Temperature Superconducting Transformer under the Influence of Abnormal Voltage ». Mobile Information Systems 2022 (29 août 2022) : 1–8. http://dx.doi.org/10.1155/2022/8256988.

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High-temperature superconducting transformers are an important research topic of superconducting technology in power applications, and electromagnetic field analysis and optimization are the basis for the design and application of high-temperature superconducting transformers. The electromagnetic field analysis of high-temperature superconducting transformers should consider the superconducting properties of the materials, that is, the properties of critical current and magnetic field. This paper aims to study the electromagnetic field analysis and optimization method of high-temperature superconducting transformer under the influence of abnormal voltage. Due to the energy loss of high-temperature superconducting transformers, in order to study the economy and reliability of high-temperature superconducting transformers, in this paper, the core loss, winding AC loss, and coil power consumption of high-temperature superconducting transformers are analyzed under normal operation and short-circuit fault conditions, respectively. The power and stress on the windings are analyzed. In order to take into account the current-carrying capacity, short-circuit loss, and short-circuit electromotive force of superconducting windings in normal operation, a concentrically placed double-cake coil structure is selected in this paper, and according to different optimization objectives, a global optimization method is used to evaluate the structure of the coil. The structural parameters of the high-temperature superconducting transformer are optimized, including the structural parameters of the magnetic conducting ring. It is found that that abnormal voltage will affect the electromagnetic field of high-temperature superconducting transformers, including winding circulating current, leakage magnetic field, and current distribution.

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Rigot, Valentin, Tanguy Phulpin, Jihen Sakly et Daniel Sadarnac. « A New 7 kW Air-Core Transformer at 1.5 MHz for Embedded Isolated DC/DC Application ». Energies 15, n^o 14 (19 juillet 2022) : 5211. http://dx.doi.org/10.3390/en15145211.

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This paper presents the study of air-core transformers for electric vehicles, developing them for medium-power (tens of kWs) converter applications specifically used at a high frequency. Air-core transformers have the advantage of lacking magnetic saturation and iron losses, making them suitable for high-frequency applications. We designed and manufactured a transformer for a determined frequency and inductance value. The design of this passive component aims to both keep the magnetic field inside the transformer and manage the thermal energy efficiently. The electrical, magnetic, and thermal properties are simulated and then verified by experiments with a specific test bench. The transformer reaches high performances for a higher frequency than usual for an equivalent power transfer in automotive applications.

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Fokeev, A. E., et I. N. Tumakov. « Analysis of Operating Modes of Oil-Immersed Power Transformers with a Voltage of 10 (6) / 0.4 kV ». Vestnik IzhGTU imeni M.T. Kalashnikova 24, n^o 4 (2021) : 80–91. http://dx.doi.org/10.22213/2413-1172-2021-4-80-91.

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The rate of thermal aging of the power transformers windings insulation depends on the effects of the electric field, mechanical stresses, temperature and processes that cause changes in these factors. A calculation algorithm is considered that allows determining the temperature of the most heated point of the windings of an oil power transformer at known values of the load current and ambient temperature. Calculation of the most heated winding point temperature and the rate of thermal aging of insulation for an oil power transformer at different ambient temperatures during the year, different values and different spectral composition of the electric load current showed that in some cases it is possible to violate the permissible operating conditions of power transformers. According to the calculation results, the dependences of the thermal aging rate of insulation on the ambient temperature are constructed, with different load parameters and different load coefficients of power transformers. For the considered modes, in the warm season, the value of the thermal aging rate of insulation significantly exceeds the nominal value. Based on mathematical models of oil power transformers with natural and forced oil circulation, expressions are obtained for determining the coefficient of reduction of the oil power transformers permissible load when the ambient temperature exceeds the normal value of 20 °C. On the basis of these expressions, for practical use, the dependences of the coefficient of reduction of the permissible load on the ambient temperature are constructed. The influence of ambient temperature must be taken into account when choosing the power of oil power transformers, for which it is assumed to operate in full redundancy mode or high load factor values (³ 0.8) in normal mode. To ensure the normative service life of the insulation of the windings, it is necessary to determine the design power of oil power transformers using the coefficient of reduction of the permissible load under the influence of higher harmonics of the current and the coefficient of reduction of the permissible load under the influence of ambient temperature.

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Thango, Bonginkosi A., et Pitshou N. Bokoro. « Defining and Specifying Design Considerations for Distribution Transformers in Large-Scale Solar Photovoltaic Plants ». Energies 15, n^o 8 (9 avril 2022) : 2773. http://dx.doi.org/10.3390/en15082773.

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In the new era of the renewable energy market in South Africa, there is a knowledge gap in the technical standards relating to distribution transformers, which are exclusively intended to serve in large-scale solar photovoltaic (PV) applications. The problem arises from the reality that these transformers are compelled to facilitate an environment with a potentially high risk of an unacceptable level of harmonics and distortion. What manufacturers currently need is a comprehensive transformer specification for DT transformers in PV applications, as the standards currently in use for regular transformers have so far proven to be inadequate. The latter triggers the need for this work to contribute to the advancement of this knowledge gap by mapping a comparative analysis of defining and specifying the design considerations for solar PV transformers. Initially, the computation of the various transformer losses at multifaceted active-part structures under normal conditions by employing the proposed finite element analysis (FEA) is presented. Then, two design case studies are described and the harmonic load current content to which the transformer will be susceptible during operation is specified and used for the analysis. Lastly, the design losses computed using the proposed FEA are substantiated using practical measurements.

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Matsuo, Y., M. Kitaoka et F. Nakao. « Present Power supply Transformers and Their Design. » Journal of the Magnetics Society of Japan 24, n^o 4−2 (2000) : 831–34. http://dx.doi.org/10.3379/jmsjmag.24.831.

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