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1
Dai, Jing, and Zhi Hua Li. "Analysis of the Energy Efficiency Grades Detection for Power Transformers." Advanced Materials Research 328-330 (September 2011): 1003–7. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.1003.
Анотація:
There is a lot of power loss in the power transmission, and the loss comes from power transformers contribute very much to this. So the implement of energy efficiency grade for power transformers has great significance to the development of power transformer, which can wash out the high energy-consuming transformer, decrease the power loss, and increase the efficiency of power transmission. The energy consumption of transformer consists of no load loss and load loss. In this test, I analyze the experiments for no load loss and load loss with the “Minimum allowable values of energy efficiency and energy efficiency grades for power transformers”, ascertaining the transformer’s efficiency grade.
2
Баширов, М., Mussa Bashirov, Азат Хисматуллин, Azat Hismatullin, И. Прахов, and I. Prahov. "Increasing of Power Oil-Filled Transformers’ Operation Reliability and Safety." Safety in Technosphere 7, no. 2 (January 23, 2019): 15–21. http://dx.doi.org/10.12737/article_5c35cc6e2354f7.79418159.
Анотація:
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.
3
Orosz, Tamás, and István Vajda. "Design Optimization with Geometric Programming for Core Type Large Power Transformers." Electrical, Control and Communication Engineering 6, no. 1 (October 23, 2014): 13–18. http://dx.doi.org/10.2478/ecce-2014-0012.
Анотація:
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.
4
Kim, Jinwook, Do-Hyeon Kim, Jieun Kim, and Young-Jin Park. "Wireless Power Transfer between Two Self-Resonant Coils over Medium Distance Supporting Optimal Impedance Matching Using Ferrite Core Transformers." Energies 14, no. 24 (December 17, 2021): 8540. http://dx.doi.org/10.3390/en14248540.
Анотація:
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.
5
Kefalas, Themistoklis D., and Antonios Kladas. "Reduction of Power Grid Losses by Using Energy Efficient Distribution Transformers." Materials Science Forum 721 (June 2012): 269–74. http://dx.doi.org/10.4028/www.scientific.net/msf.721.269.
Анотація:
The importance of distribution transformer no-load loss on the operation of modern electrical grids is often underestimated. Internationally, distribution transformer no-load loss constitutes nearly 25% of the transmission and distribution losses of electrical grids. The losses in European Union distribution transformers are estimated at about 33 TWh/year whereas, reactive power and harmonic losses add a further 5 TWh/year. In the Greek electrical grid the no-load losses of 140,000 distribution transformers are estimated at about 490 GWh/year. This paper has two goals the first one is to illustrate the significance of distribution transformer no-load loss in periods of high electric energy cost and the second goal is the presentation of a novel numerical methodology for wound core transformers no-load loss analysis, enabling to determine the economically and technically optimum transformer for every use.
6
Manisha, Kulraj Kaur, Naveen Kumar Sharma, Jashandeep Singh, and Deepika Bhalla. "Performance Assessment of IEEE/IEC Method and Duval Triangle technique for Transformer Incipient Fault Diagnosis." IOP Conference Series: Materials Science and Engineering 1228, no. 1 (March 1, 2022): 012027. http://dx.doi.org/10.1088/1757-899x/1228/1/012027.
Анотація:
Abstract Power transformers are among the most important equipment in a power system. The assessment of the transformer’s condition which is connected to a system is needed to avoid disastrous failures and the subsequent power outages. Although transformers are highly dependable and efficient, but are always under the influence of thermal, electrical stresses which are caused due to the deterioration of transformer insulation. Internal faults in a transformer can be classified as incipient faults and internal short circuit faults. The former type of faults develops over an extended period of time and lead to the degradation of insulation. Incipient faults are generally the result of deterioration of the dielectric strength of transformer mineral oil due to hydrolysis, pyrolysis, and oxidation, which result in the formation of gases that are collected in the gap between the oil and tank and partially get dissolved in it. If incipient conditions are not corrected timely, they may finally lead to collapse of the system where such a transformer is installed. Dissolved Gas Analysis (DGA) methods are extensively accepted by utilities for detection of developing faults. In this work, the brief study of two of the prevalent DGA methods for identification of incipient faults has been carried out. The methods that have been studied are IEEE/IEC Ratio Method and Duval’s Triangle Method. The published DGA data where the actual fault is known is used for identification of the incipient faults and the results have been compared.
7
DeCristofaro, Nicholas. "Links of Science & Technology." MRS Bulletin 23, no. 5 (May 1998): 50–56. http://dx.doi.org/10.1557/s0883769400030451.
Анотація:
On April 13, 1982, the Duke Power Company energized an experimental pad-mount distribution transformer in Hickory, North Carolina. The transformer, manufactured by General Electric, provided electric power to a local residence. That same month, the Georgia Power Company installed a similar transformer, made by Westinghouse Electric, atop a utility pole in Athens, Georgia. It supplied electricity for the exterior lights at the Westinghouse Newton Bridge Road plant. These devices shown in Figure 1 were unique among the nearly 40 million distribution transformers in service in the United States because their magnetic cores were made from an Fe–B–Si amorphous-metal alloy. This new material, produced by Allied-Signal (formerly Allied Chemical), was capable of magnetizing more efficiently than any electrical steel. By replacing grain-oriented silicon steel in the transformer cores, the amorphous metal reduced the core losses of the transformers by 75%.Although distribution transformers are relatively efficient devices, often operating at efficiencies as high as 99% at full load, they lose a significant amount of energy in their use. Because of the number of units in service, coupled with the fact that the core material is continuously magnetized and demagnetized at line frequency, transformers account for the largest portion of the energy losses on electric power distribution systems. It is estimated that over 50 × 109 kWh are dissipated annually in the United States in the form of distribution transformer core losses. At today's average electricity generating cost of $0.035/kWh, that energy is worth over $1,500 million.
8
Hanin, Yu I., O. V. Rodionova, A. P. Panchishkin, M. A. Zaichkina, and Ya E. Shakhbazova. "On the efficiency of power transformers with «star-zig-zag with zero» winding connection scheme in rural electricity networks supplying household consumers." Journal of Physics: Conference Series 2060, no. 1 (October 1, 2021): 012004. http://dx.doi.org/10.1088/1742-6596/2060/1/012004.
Анотація:
Abstract The dependencies of the loss coefficient on the value of reverse- and zero-sequence current unbalance coefficients are obtained, allowing estimating the energy efficiency of power transformers operation at different unbalance characteristics. The electricity losses were calculated from these dependencies and from data obtained from instrumental measurements at rural substations supplying household consumers. It was obtained that the power transformer with «the star-zigzag with zero» scheme is 6 times more energy efficient than the power transformer with «the star–star with zero» scheme. However, with small values of the currents asymmetry (for five cases studied), the power transformer with «the star-zigzag with zero» scheme has overestimated power losses.
9
Gilfanov, K. H., N. Tien, R. N. Gaynullin, and I. Hallyyev. "Energy efficient heat supply system for electric power facilities." E3S Web of Conferences 124 (2019): 01011. http://dx.doi.org/10.1051/e3sconf/201912401011.
Анотація:
The aim of the work is to confirm the possibility of creating an energy-saving heat supply system for power facilities by using computer modelling, analysis of the potential use of heat losses of electromagnetic energy in magnetic circuits and windings of transformers of substations, as well as the development of schemes for heat recovery losses for heat supply of power facilities. Computer simulation of electromagnetic and thermophysical processes in the power oil-filled transformer is carried out. Energy losses in windings, hysteresis and eddy currents in the magnetic circuit, as well as temperature and heat flux fields in the longitudinal and transverse sections of the oil-filled power transformer in idle and short-circuit modes were determined. The transformer performance in terms of heat recovery losses was evaluated. The possible volumes of heat extraction for heat supply depending on the power of the transformer are determined. The automated oil-water system of heat recovery of the transformer for heating of electric power facilities is proposed. The significance of the obtained results for the construction industry is to confirm the possibility of creating an energy-saving heat supply system for electric power facilities while maintaining the operational characteristics of the transformer based on computer modelling; the significant potential of using the heat loss of power transformers of substations is shown, an automated heat supply system for electric power facilities is proposed.
10
Hu, Xiao Ping, Bin Chen, Ye Long Zhong, and Jun Ming Xu. "Design of UHF Thin Film Transformer and Research of its S-Parameter Performance." Advanced Materials Research 482-484 (February 2012): 1542–46. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1542.
Анотація:
A novel spiral stacked thin film transformer was designed based on Si IC technology in this paper. And also, the stacked air core and ferrite core thin film transformers with different turns ratio were prepareed. Then, the S-parameter performance of these two kinds of transformers were measured. The measurement results show that the magnetic core thin film transformer has a better electronic transmission performance. It obtains maximum transmission efficiency 93.7% at the frequency range from 10MHz to 20GHz, and the air core transformer obtains maximum 89% at the same frequency range. Many testings show that ferrite core thin film transformer with turns ratio 1:1 can obtain the transmission efficiency over 60% at the frequency range from 2GHz to 16GHz.
11
Lankin, Anton, Alexey Baklanov, and Igor Lankin. "Analysis of diagnostic methods and functional state monitoring of power oil transformers in electrical substations." E3S Web of Conferences 135 (2019): 01021. http://dx.doi.org/10.1051/e3sconf/201913501021.
Анотація:
In this paper, we analyze the methods of diagnosis and control the functional state of power oil transformers in electrical substations. Oil transformers are the most efficient converters of electrical energy, which is reflected in a higher efficiency in comparison with dry transformers. Oil transformers are designed to work with power grids in large industrial complexes where energy conversion is required to protect equipment from sudden voltage surges. The high loads associated with this work require timely diagnosis and maintenance of transformers. The article discusses the most commonly used methods for diagnosing deviations of the technical parameters of electrical substations in the process of their operation. The authors proposed a method of impedance series-parallel identification, which allows not only to determine the equivalent circuit of the power oil transformer, but also to diagnose possible malfunctions. Functional circuits of the device for impedance series-parallel identification of faults in power oil transformers have been developed.
12
Lansberg, A. A., A. V. Vinogradov, and A. V. Vinogradova. "The structure of the park of power transformers with a higher voltage of 6-10 Kv on the example of the electric grid organization of the branch of pjsc «Rosseti center»-«Orelenergo», serving rural electric networks." Power engineering: research, equipment, technology 23, no. 5 (January 9, 2022): 34–45. http://dx.doi.org/10.30724/1998-9903-2021-23-5-34-45.
Анотація:
THE PURPOSE. Evaluation of the power transformer fleet 6-10/0,23-0,4 kV on the example of a branch of PJSC «Rosseti Center»-«Orelenergo».METHODS. In the work, based on the database of the branch of PJSC «Rosseti Center»-«Orelenergo», an analysis was made of the fleet of power transformers with a higher voltage of 6-10 kV in terms of their number, circuits and groups of connection of windings, rated power, terms of service, as well as energy efficiency classes, taking into account the current standards of the technical organization of PJSC «Rosseti».RESULTS. According to the results of the study, it was revealed that among the transformer fleet of the branch of PJSC «Rosseti Center»-«Orelenergo», the number of which is 6026 units, 4528 (73% of the total number) transformers have a circuit and a group of winding connections Y/Y0. The most numerous are transformers with rated capacities of 63 kVA, 100 kVA, 160 kVA, 250 kVA (respectively 853, 1454, 1252, 802 pieces of equipment). It was also revealed that only 268 transformers out of 6206, i.e. 4.3% of the total amount comply with the standard of PJSC «Rosseti» in terms of modern requirements for the level of energy efficiency class.CONCLUSION. A variant of the strategy for replacing power transformers in the branch of PJSC «Rosseti Center»-«Orelenergo» is proposed, within the framework of which trasformers with a given design, circuit and winding connection group, rated capacities and energy efficiency classes are replaced. The implementation of the strategy proposed in the work will make it possible to reduce total electricity losses by 2.3%, as well as increase the share of energy-efficient transformers from 4.3% to 20.4% in the branch of PJSC «Rosseti Center»-«Orelenergo».
13
Gracia-Velásquez, David Gilberto, Andrés Steven Morales-Rodríguez, and Oscar Danilo Montoya. "Application of the Crow Search Algorithm to the Problem of the Parametric Estimation in Transformers Considering Voltage and Current Measures." Computers 11, no. 1 (January 6, 2022): 9. http://dx.doi.org/10.3390/computers11010009.
Анотація:
The problem of the electrical characterization of single-phase transformers is addressed in this research through the application of the crow search algorithm (CSA). A nonlinear programming model to determine the series and parallel impedances of the transformer is formulated using the mean square error (MSE) between the voltages and currents measured and calculated as the objective function. The CSA is selected as a solution technique since it is efficient in dealing with complex nonlinear programming models using penalty factors to explore and exploit the solution space with minimum computational effort. Numerical results in three single-phase transformers with nominal sizes of 20 kVA, 45 kVA, 112.5 kVA, and 167 kVA demonstrate the efficiency of the proposed approach to define the transformer parameters when compared with the large-scale nonlinear solver fmincon in the MATLAB programming environment. Regarding the final objective function value, the CSA reaches objective functions lower than 2.75×10−11 for all the simulation cases, which confirms their effectiveness in minimizing the MSE between real (measured) and expected (calculated) voltage and current variables in the transformer.
14
Adi Wirajaya, I. Putu, I. Wayan Rinas, and I. Wayan Sukerayasa. "Studi Analisa Pengaruh Total Harmonic Distortion (THD) terhadap Rugi-Rugi, Efisiensi, dan Kapasitas Kerja Transformator pada Penyulang Kerobokan." Jurnal SPEKTRUM 6, no. 2 (June 1, 2019): 121. http://dx.doi.org/10.24843/spektrum.2019.v06.i02.p17.
Анотація:
Kerobokan feeder supply electrical energy in the area of Kerobokan. This feeder supplies 67 distribution transformers that serve a variety of customers with nonlinier electrical loads. Nonlinier electrical loads cause harmonics which adversely affect customers and power system equipment, especially distribution transformers. In Kerobokan feeder, only 3 (4.5%) of the 67 transformers has THDi content that according with the IEEE 519-2014 standard and 64 (95.5%) of the 67 transformers has a high THDi content and exceed the IEEE 519-2014 standard. For this reason, the power losses, efficiency, and work capacity of the transformer are analyzed due to the effect of THDi. This study uses a direct measurement method in all transformers in the Kerobokan feeder and simulation on the ETAP Powerstation program. The results of the analysis showed that total power losses without being affected by THDi for all transformers were 49.4 kW and after being affected by THDi were 591.71 kW. The highest THDi content is in the KA 0992 transformer is 24.8% which results in an increased in power losses is 12.02 kW or 12.02% of its capacity and a decreased in efficiency is 12.66% and has a decreased in work capacity is 19.9%. While the smallest THDi content is found in the DB 449 transformer is 6.8% which results in an increased in power losses is 2.2 kW or 0.88% of its capacity and a decreased efficiency is 1.01% and has a decreased in work capacity is 2.7%.
15
P.K., Preetha, and P. S. Chandramohanan Nair. "Modified Distribution Transformer for Enhancing Power Quality in Distribution Systems." International Journal of Power Electronics and Drive Systems (IJPEDS) 7, no. 4 (December 1, 2016): 1386. http://dx.doi.org/10.11591/ijpeds.v7.i4.pp1386-1392.
Анотація:
<p>The percentage of non-linear loads in the power distribution sector is increasing day by day. Harmonics injected by these non-linear loads circulate in the delta windings of the conventional distribution transformer thereby increasing the temperature and losses. This reduces the efficiency and life of the transformers. In a modified distribution transformer configuration proposed recently, called star-star-delta_utilized configuration (YYD_utilized), the harmonics circulating in the delta winding was utilized and the drainage power thus recovered was used to power auxiliary loads. This paper presents the experimental studies conducted on YYD_utilized distribution transformer. When compared to conventional star-star, delta-star and star-star-delta transformers, the new configuration of YYD_utilized transformer has shown considerable improvement in transformer efficiency. The results obtained show that when the power from the circulating harmonics is recovered and utilized, it not only improves transformer efficiency but also improves the power factor and reduces the harmonic distortions at the primary side of the transformer. The results obtained also suggest the existence of maximum power point or an optimum loading for the recovered harmonic power.</p>
16
GLINKA, Tadeusz. "Power Losses and Efficiency in Transformers." AUTOMATYKA, ELEKTRYKA, ZAKLOCENIA 12, no. 2(44)2021 (June 30, 2021): 68–73. http://dx.doi.org/10.17274/aez.2021.44.04.
Анотація:
Energy efficiency of transformers has been defined in the paper. The continuous progress noted in technology of electrical steel used for transformer laminations results in decreased lossiness and increase of flux density saturation in the core. Therefore, conditions are established for decreasing core weight and, to a lesser degree, decreasing winding weight as well. The examples of idle and load power losses have been provided for distribution transformers manufactured in 1960s and for those manufactured now. The European Commission [8] and European Standards have ruled that further decrease in power losses and increase in efficiency of newly-installed transformers must come into effect by 1st July, 2021.
17
Micu, D. D., A. G. Rusina, O. V. Naumov, and A. N. Gorlov. "Calculation of loading ability of power transformers taking into account electromechanical characteristics." E3S Web of Conferences 124 (2019): 02006. http://dx.doi.org/10.1051/e3sconf/201912402006.
Анотація:
This paper presents calculation of operation modes of power transformers aiming at determination of optimum loading at which the transformer performance coefficient reaches its maximum. Options for increasing the efficiency of power transformers operation at industrial enterprises are proposed.
18
Kim, Ki Jin, Tae Ho Lim, S. H. Park, and K. H. Ahn. "A High Efficiency CMOS Power Amplfieir with a Diode Linearizer and Voltage Combining Transformers." Applied Mechanics and Materials 110-116 (October 2011): 5500–5504. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.5500.
Анотація:
This paper proposes a high efficiency power amplifier with a diode linearizer and voltage combining transformers in a standard 0.13-μm TSMC CMOS technology. The 3-D simulated transformer adopts multi-finger architecture which provides low insertion loss and allows high current capacity on the transformer. With the 4 differentially cascaded connected multi-finger transformers, the amplifier delivers more than 1W output power under 1.8 V supply condition. To enhance linearity of the power amplifier, the diode configuration bias circuit is used in this paper. With all integration of transformers, balun, diode bias circuits and same 4 diff-amps, the prototype Class AB Power Amplifier shows 32dBm saturation power at 2.4 GHz. Due to the diode linearizer the output P1dB is 30.8 dBm with 28 % Power Added Efficiency.
19
Wang, Jia Ying, Yue Zhang, Guo Qing Zhang, and Zhi Zhong Guo. "Body-Efficiency Character Analysis for Mini Optical Current Transformer." Advanced Materials Research 679 (April 2013): 35–39. http://dx.doi.org/10.4028/www.scientific.net/amr.679.35.
Анотація:
All-electric ship is the development direction of ship in future. It’s necessary to do some further microminiature research on the optical current transformer used in all-electric ship. The microminiature research has to face the problem which is the influence of environment changes on mini-optical current transformer’s performance. Base on the theoretical model, the influence of environment changes on mini-optical current transformer’s performance has been studied in this paper. For the impact of environmental factors, temperature field and interference field of optical current transformer have been analyzed in detail. The model related temperature stabilization, anti-magnetic field interference feature, response feature with different magneto-optical material’s length. The optimal solution of the body-efficiency character model has been calculated for the design of mini-optical current transformer.
20
Somkun, Sakda, Toshiro Sato, Viboon Chunkag, Akekachai Pannawan, Pornnipa Nunocha, and Tawat Suriwong. "Performance Comparison of Ferrite and Nanocrystalline Cores for Medium-Frequency Transformer of Dual Active Bridge DC-DC Converter." Energies 14, no. 9 (April 23, 2021): 2407. http://dx.doi.org/10.3390/en14092407.
Анотація:
This article reports an investigation into ferrite and nanocrystalline materials for the medium-frequency transformer of a dual active bridge DC-DC converter, which plays a key role in the converter’s efficiency and power density. E65 MnZn ferrite cores and toroidal and cut nanocrystalline cores are selected for the construction of 20-kHz transformers. Transformer performance is evaluated with a 1.1-kW (42–54 V)/400 V dual active bridge DC-DC converter with single-phase shift and extended phase shift modulations. The experimental results indicate that the toroidal nanocrystalline transformer had the best performance with an efficiency range of 98.5–99.2% and power density of 12 W/cm3, whereas the cut-core nanocrystalline transformer had an efficiency range of 98.4–99.1% with a power density of 9 W/cm3, and the ferrite transformer had an efficiency range of 97.6–98.8% with a power density of 6 W/cm3. A small mismatch in the circuit parameters is found to cause saturation in the nanocrystalline toroidal core, due to its high permeability. The analytical and experimental results suggest that cut nanocrystalline cores are suitable for the dual active bridge DC-DC converter transformers with switching frequencies up to 100 kHz.
21
Abdullah, Mohammad A., and Barween R. Kareem. "The Effect of Adding Series Capacitor and Phase Shifting Transformer on Power System Performance." Tikrit Journal of Engineering Sciences 23, no. 4 (December 31, 2016): 81–92. http://dx.doi.org/10.25130/tjes.23.4.09.
Анотація:
Promoting power system performance is regarded as one of the essential issues for a sustainable customer service, alongside with the expansion of the inductive loads and population increase. The study aims to improve and promot power system performance by using series capacitors and phase – shifting transformers. The capacitors and transformers are used separately in the system, then they are used together in two separate lines for two load cases: the base load and the increasing the base load 25%. The system power flow has been examined by utilizing Matlab version 7.6. The study shows that the efficiency of both series capacitors and phase – shifting transformers in improving line loadability, whether used together or separately. The highest rate for improving line loadability was 53.15% when using series capacitor in the line 1 – 5. As for the transformer, the highest rate was 53.25% in the line 11–5. The study has also shown that adding series capacitor and phase–shifting transformer simultaneously to the system is more efficient in promoting and improving system performance than adding them separately. The current study has been applied on the test system IEEE with 14 buses and 20 transmission lines.
22
Alyunov, A. N., O. S. Vyatkina, A. V. Udaratin, and D. A. Zaripova. "Technical and economic efficiency of proactive diagnostic systems for power transformers." E3S Web of Conferences 178 (2020): 01081. http://dx.doi.org/10.1051/e3sconf/202017801081.
Анотація:
The expediency of using systems of proactive diagnostics of power transformers is substantiated. The diagnostic system expands the possibilities of analyzing the transformer condition in operating mode. It allows one to minimize the expected damage from interruptions in power supply and equipment failure. The results can be used in world practice during construction of various control systems to identify developing transformer defects caused by windings deformations.
23
Jarrahi, Mohammad Amin, Emad Roshandel, Mehdi Allahbakhshi, and 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, no. 2 (March 4, 2019): 862–77. http://dx.doi.org/10.1108/compel-06-2017-0229.
Анотація:
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.
24
Albrechtowicz, Paweł. "Phase-Shifting Transformer Efficiency Analysis Based on Low-Voltage Laboratory Units." Energies 14, no. 16 (August 17, 2021): 5049. http://dx.doi.org/10.3390/en14165049.
Анотація:
Phase-shifting transformers are effective elements used to control power flows in many power systems. Their positive influence on power flows has been proved in the literature. However, the efficiency of phase-shifting transformers has not been analyzed, especially not with regard for their various types. This study is therefore focused on the efficiency question with respect to electrical energy parameters. Research was performed on a laboratory phase-shifter unit with longitudinal and quadrature voltage regulation, and then these results were correlated to the simulation model equivalent. Laboratory transformer parameter data were used to prepare asymmetrical and symmetrical phase-shifting transformer simulation models. Simulation results were then used to compare the electrical properties and efficiency of all the types of phase-shifting transformer considered. All phase-shifting transformer types had a significant impact on the transmitted active power, but each type had different features. The symmetrical unit had the lowest power losses and a stable output voltage level compared to the asymmetrical one, which increased the output voltage, while the quadrature voltage also grew. These features must be considered, taking into account power system conditions such as the voltage variability profile and active power transfer demand. In this study, we propose the construction of an asymmetrical controllable phase-shifting transformer in order to achieve flexible control.
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Yoon, Yeunggurl, Yongju Son, Jintae Cho, SuHyeong Jang, Young-Geun Kim, and Sungyun Choi. "High-Frequency Modeling of a Three-Winding Power Transformer Using Sweep Frequency Response Analysis." Energies 14, no. 13 (July 3, 2021): 4009. http://dx.doi.org/10.3390/en14134009.
Анотація:
A power transformer is an essential device for stable and reliable power transfer to customers. Therefore, accurate modeling of transformers is required for simulation-based analysis with the model. The paper proposes an efficient and straightforward parameter estimation of power transformers based on sweep frequency response analysis (SFRA) test data. The method first develops a transformer model consisting of repetitive RLC sections and mutual inductances and then aligns the simulated SFRA curve with the measured one by adjusting parameters. Note that this adjustment is based on individual parameter impacts on the SFRA curve. After aligning the two curves, the final transformer model can be obtained. In this paper, actual single-phase, three-winding transformer model parameters were estimated based on field SFRA data, showing that SFRA curves simulated from the estimated model are consistent with the measured data.
26
Alyunov, Alexander, Olga Vyatkina, and Alexander Nemirovskiy. "On efficiency of digital system of power transformer proactive diagnostics." Proceedings of Irkutsk State Technical University 24, no. 5 (October 2020): 966–76. http://dx.doi.org/10.21285/1814-3520-2020-5-966-976.
Анотація:
The purpose of the paper is to diagnose the state of a power transformer by determining its equivalent circuit parameters by means of synchronized vector measurements of currents and voltages in the transformer normal operation mode without shutdowns, which makes it possible to increase the reliability of relay protection operation. A cost - effective method for proactive diagnostics of power transformers is proposed. Through monitoring of additional parameters (short circuit resistance, active and inductive resistance of the positive sequence, active and inductive resistance of the negative sequence) it can increase the speed and accuracy of detecting possible internal short circuits arising due to winding damage or high-voltage transformer bushings without diagnosed transformer disconnection from the network. The method allows to estimate the transformer health index and serviceability by the difference between the calculated parameters of the equivalent circuit and the passport values of the parameters. Having conducted the damage causedependent analysis of the number of power transformer damages, the authors determined total economic losses that include the losses caused by equipment damage and losses caused by the interruptions in consumer power supply. The total economic losses for a power transformer with a rated power of 63 MVA amounted to 10687402 rubles. It is shown that the diagnostic system expands the possibilities of analyzing the transformer state in operating modes, allows to pr event the approaching of the damage moment and occurrence of sudden accidents as well as minimizes the expected damage from shutdowns and equipment failure. A hardware and software complex is proposed for the diagnostics of power transformer internal damage. The given main characteristics of the proposed hardware and software complex include the number of measuring channels, accuracy class, sampling frequency, and others. The results of the work expand the possibilities of analyzing the transformer state in the operating mode and can be used in the world practice of creating various monitoring systems designed to identify the defects developing in transformers caused by winding deformation.
27
Bulucea, Cornelia A., Doru A. Nicola, Nikos E. Mastorakis, and Carmen A. Bulucea. "Three-phase power transformer modelling in AC/DC traction substations." MATEC Web of Conferences 292 (2019): 01006. http://dx.doi.org/10.1051/matecconf/201929201006.
Анотація:
Three-phase power transformer is one of the most important elements in the electric power systems, and it plays a significant role in terms of energy savings. Since the efficiency standards can be expressed in terms of electrical efficiency, in an attempt to improve the transformer efficiency, in this study an enhancement of three-phase power transformer modelling with space phasors is presented. There are established the equations with space phasors of the three-phase transformer with symmetrical compact core. This equations system can be used to analyze the dynamic regimes of three-phase transformers. In this paper have been analyzed some aspects of three-phase power transformer operation in a AC/DC traction substation.
28
León-Martínez, Vicente, Elisa Peñalvo-López, Clara Andrada-Monrós, Jorge Cano-Martínez, Amparo León-Vinet, and Laura Molina-Cañamero. "Procedure for Improving the Energy, Environmental and Economic Sustainability of Transformation Houses." Applied Sciences 12, no. 9 (April 21, 2022): 4204. http://dx.doi.org/10.3390/app12094204.
Анотація:
A procedure for improving the energy, economic and environmental sustainability of the transformation houses in low-voltage distribution networks is described in this paper. This procedure is based on the reduction of the transformer consumption, copper and core losses. Likewise, the procedure distinguishes between transformation houses with old and new transformers. The reduction of core losses, replacing transformers with others of lower power or that are more efficient, achieves significant improvements in energy and environmental aspects. The reduction of copper losses, and applying reactive compensation techniques, such as harmonic filtering and load balancing, applied in old and new transformation houses, have a greater impact on cost savings, especially when there are capacitive consumptions, as the Circular 3/2020 of the National Markets and Competition Commission of Spain determines. The procedure has been applied to an industrial transformation house, which has an old 1600 kVA transformer, resulting in significant economic savings and CO2 reductions of more than 60%, after replacing the current transformer with a more efficient one.
29
Choi, Se-Eun, Hyunjin Ahn, Joonhoi Hur, Kwan-Woo Kim, Ilku Nam, Jaehyouk Choi, and Ockgoo Lee. "A Fully Integrated Compact Outphasing CMOS Power Amplifier Using a Parallel-Combining Transformer with a Tuning Inductor Method." Electronics 9, no. 2 (February 3, 2020): 257. http://dx.doi.org/10.3390/electronics9020257.
Анотація:
This work presents a compact on-chip outphasing power amplifier with a parallel-combining transformer (PCT). A series-combining transformer (SCT) and PCT are analyzed as power-combining transformers for outphasing operations. Compared to the SCT, which is typically used for on-chip outphasing combiners, the PCT is much smaller. The outphasing operations of the transformer combiners and class-D switching PAs are also analyzed. A tuning inductor method is proposed to improve the efficiency of class-D power amplifiers (PAs) with power-combining transformers in the out-of-phase mode. The proposed PA was implemented with a standard 0.18 µm CMOS process. The measured maximum drain efficiency is 37.3% with an output power of 22.4 dBm at 1.7 GHz. A measured adjacent channel leakage ratio (ACLR) of less than −30 dBc is obtained for a long-term evolution (LTE) signal with a bandwidth of 10 MHz.
30
Ying, Liming, Donghui Wang, Guodong Wang, and Wenyi Wang. "Acoustic characteristic analysis of power transformers in urban communities based on a combined finite and boundary element method." Indoor and Built Environment 29, no. 2 (June 19, 2019): 208–20. http://dx.doi.org/10.1177/1420326x19857452.
Анотація:
Power transformers in substations are common sources of noise in residential areas of neighbourhoods. A quantified and visualized analysis of the power transformer acoustic characteristics is a prerequisite for the suppression of audible noise from the corresponding substation. In this study, based on a combined finite and boundary element method, a full-sized 3D power transformer multiphysics coupling model, which is aimed at realizing high accuracy and improving the computational efficiency, was developed. After validation of the numerical method using comparative tests, profile analyses in the near-field and far-field in the extended planes and three-dimensional areas of a power transformer were conducted to characterize the external acoustic field. The calculation results included the distribution of the spatial sound pressure levels of the power transformer at multiple levels in the frequency domain. These spatial sound pressure levels can be used to guide the efficient measurement of the external acoustic field of a power transformer and the soundscape planning around a substation, and the differentiated design of the sound absorption structure inside a substation.
31
Sutjipto, Rachmat, Anang Dasa Novfowan, and Rohmanita Duanaputri. "STUDI PERENCANAAN PENINGKATAN KINERJA TRAFO DISTRIBUSI DENGAN RELOKASI ANTARA 2 BUAH TRAFO." JURNAL ELTEK 17, no. 2 (November 11, 2019): 69. http://dx.doi.org/10.33795/eltek.v17i2.161.
Анотація:
Dalam penggunaan trafo diketahui bahwa terdapat beberapa trafo yang dibebani tidak optimal sesuai dengan standar yang ada. Sebagai contoh, berdasarkan hasil pengukuran pada bulan Agustus 2015 pada PT. PLN (Persero) Rayon Pare diketahui bahwa pada gardu EF283 di Penyulang Bendo beban puncaknya telah mencapai 103,59 % sedangkan pada gardu EF070 di Penyulang Sambirejo pada beban puncaknya hanya mencapai 32,62 %. Kondisi tersebut akan berakibat negatif pada kinerja dari trafo dimana pada pembebanan yang terlalu tinggi pada trafo akan berakibat trafo tersebut overload dan berimbas mengurangi umur ekonomis dari trafo dan dapat mengakibatkan kerusakan pada trafo akibat panas yang berlebihan. Sebaliknya, jika trafo dibebani jauh dibawah kapasitasnya maka efisiensi trafo akan rendah.
Untuk meningkatkan kinerja dari kedua trafo tersebut di atas maka digunakan cara relokasi diantara kedua trafo tersebut dan diharapkan trafo pada gardu EF283 tidak terjadi overload sedangkan prosentase pembebanan gardu EF070 diharapkan meningkat sehingga efisiensi trafo meningkat. Setelah dianalisa dan dibandingkan antara kondisi sebelum dan setelah relokasi pada aspek % pembebanan, effisiensi dan faktor kebutuhan, juga dianalisa tentang pertumbuhan beban dengan menggunakan metode least factor maka dapat disimpulkan bahwa sebelum dilaksanakan relokasi harus dipertimbangkan beberapa persyaratan untuk dilaksanakannya relokasi. Selain itu diketahui bahwa effisiensi trafo akan lebih besar (optimal) jika dibandingkan antara kondisi sebelum (trafo EF283 dan EF070 adalah 97,54 % dan 97,42 %) dan setelah relokasi (98,44 % dan 98,50 %). Sedangkan untuk umur trafo , umur trafo pada gardu EF283 akan relatif lebih panjang dan pada trafo di gardu EF070 akan relatif lebih pendek umur trafonya karena adanya peningkatan pembebanan walaupun effisiensi trafonya ternyata lebih baik dibandingkan sebelum relokasi.
In the use of transformers it is known that there are several transformers that are not optimally loaded according to the existing standards. For example, based on the results of measurements in August 2015 at PT. PLN (Persero) Rayon Pare is known that at EF283 substation at Bendo Feeder the peak load has reached 103.59% while at EF070 substation at Sambirejo Feeder at peak load it only reaches 32.62%. These conditions will negatively affect the performance of the transformer where overloading of the transformer will result in the transformer overloading and impacting to reduce the economic life of the transformer and can cause damage to the transformer due to excessive heat. Conversely, if the transformer is burdened far below its capacity, the transformer efficiency will be low.
To improve the performance of the two transformers, relocation between the two transformers is used and it is expected that the transformer on the EF283 substation will not overload while the percentage of EF070 substation loading is expected to increase so that the transformer efficiency increases. After analyzing and comparing the conditions before and after relocation in the aspects of% loading, efficiency and needs factors, also analyzed the load growth using the least factor method, it can be concluded that before the relocation is carried out, several conditions must be considered for the relocation. In addition, it is known that the transformer efficiency will be greater (optimal) compared to the conditions before (transformer EF283 and EF070 are 97.54% and 97.42%) and after relocation (98.44% and 98.50%). As for the life of the transformer, the life of the transformer at the EF283 substation will be relatively longer and at the transformer at the EF070 substation will be relatively shorter in the life of the transformer due to an increase in loading even though the transformer efficiency turns out to be better than before relocation.
32
Saveliev, Dmitri, Dmitri Chashin, Leonid Fetisov, Mikhail Shamonin, and Yuri Fetisov. "Ceramic-Heterostructure-Based Magnetoelectric Voltage Transformer with an Adjustable Transformation Ratio." Materials 13, no. 18 (September 9, 2020): 3981. http://dx.doi.org/10.3390/ma13183981.
Анотація:
A voltage transformer employing the magnetoelectric effect in a composite ceramic heterostructure with layers of a magnetostrictive nickel–cobalt ferrite and a piezoelectric lead zirconate–titanate is described. In contrast to electromagnetic and piezoelectric transformers, a unique feature of the presented transformer is the possibility of tuning the voltage transformation ratio K using a dc magnetic field. The dependences of the transformer characteristics on the frequency and the amplitude of the input voltage, the strength of the control magnetic field and the load resistance are investigated. The transformer operates in the voltage range between 0 and 112 V, and the voltage transformation ratio K is tuned between 0 and 14.1 when the control field H changes between 0 and 6.4 kA/m. The power at the transformer output reached 63 mW, and the power conversion efficiency was 34%. The methods for calculation of the frequency response, and the field and load characteristics of the transformer are proposed. The ways to improve performance characteristics of magnetoelectric transformers and their possible application areas are discussed.
33
Amoiralis, Eleftherios I., Marina A. Tsili, and Antonios Kladas. "Design Optimization Procedure for Amorphous Core Distribution Transformers." Materials Science Forum 721 (June 2012): 159–64. http://dx.doi.org/10.4028/www.scientific.net/msf.721.159.
Анотація:
The paper presents a design optimization procedure appropriate for distribution transformers with amorphous alloy cores. Several considerations and the main differences from the design practice of conventional transformers are presented and discussed in detail. Moreover, comparison of results present the significant benefit in the transformer energy efficiency by the selection of amorphous alloy core, despite its initial higher installation cost.
34
Sopov, Anatoliy I., and Aleksandr V. Vinogradov. "The Heating System of Agricultural Facilities Using Excess Heat Power Transformers." Elektrotekhnologii i elektrooborudovanie v APK 67, no. 1 (March 28, 2020): 42–47. http://dx.doi.org/10.22314/2658-4859-2020-67-1-42-47.
Анотація:
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.
35
Papaika, Yu A., I. M. Lutsenko, IE V. Koshelenko, and 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, no. 2 (June 30, 2021): 33–43. http://dx.doi.org/10.15588/1607-6761-2021-2-4.
Анотація:
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.
36
Zhong, Chao, and Ran Li. "Distribution Transformer Residual Life Prediction Based on the Theory of Markov." Applied Mechanics and Materials 530-531 (February 2014): 526–29. http://dx.doi.org/10.4028/www.scientific.net/amm.530-531.526.
Анотація:
It has been an important subject that how to apply transformer condition information efficiently and scientifically to judge the transformers state and predict the remaining life. This paper, in view of the distribution transformer test information, analyzed the factors affecting its residual life evaluation, and established the evaluation model of distribution transformer. Based on the existing research results and the introduction of improved Markov prediction method, it finally established a dynamic variable metric improved Markov distribution transformer life prediction model. Actual data verified the effectiveness and reasonability of the model.
37
Zhang, Xian Jin, and Bu Gen Wang. "Applications of DC Transformer in DC Distributed Generations System." Advanced Materials Research 706-708 (June 2013): 1755–58. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.1755.
Анотація:
DC transformer with high frequency and efficiency under a fixed duty cycle is widely used in dc distributed generations. In this paper, the topologies and equivalent circuits of single /bidirectional full-bridge non-resonant DC transformers are presented. And the configurations of the input-series output-parallel and input-parallel output-series DC transformers are also proposed for reducing voltage stress of power devices. The example consisting of DC transformers in a distributed generation system based on DC grid is shown. Finally, simulation results verify the feasibility.
38
Chen, Keyan, Zhengxia Zou, and Zhenwei Shi. "Building Extraction from Remote Sensing Images with Sparse Token Transformers." Remote Sensing 13, no. 21 (November 5, 2021): 4441. http://dx.doi.org/10.3390/rs13214441.
Анотація:
Deep learning methods have achieved considerable progress in remote sensing image building extraction. Most building extraction methods are based on Convolutional Neural Networks (CNN). Recently, vision transformers have provided a better perspective for modeling long-range context in images, but usually suffer from high computational complexity and memory usage. In this paper, we explored the potential of using transformers for efficient building extraction. We design an efficient dual-pathway transformer structure that learns the long-term dependency of tokens in both their spatial and channel dimensions and achieves state-of-the-art accuracy on benchmark building extraction datasets. Since single buildings in remote sensing images usually only occupy a very small part of the image pixels, we represent buildings as a set of “sparse” feature vectors in their feature space by introducing a new module called “sparse token sampler”. With such a design, the computational complexity in transformers can be greatly reduced over an order of magnitude. We refer to our method as Sparse Token Transformers (STT). Experiments conducted on the Wuhan University Aerial Building Dataset (WHU) and the Inria Aerial Image Labeling Dataset (INRIA) suggest the effectiveness and efficiency of our method. Compared with some widely used segmentation methods and some state-of-the-art building extraction methods, STT has achieved the best performance with low time cost.
39
Luna-Jiménez, Cristina, Jorge Cristóbal-Martín, Ricardo Kleinlein, Manuel Gil-Martín, José M. Moya, and Fernando Fernández-Martínez. "Guided Spatial Transformers for Facial Expression Recognition." Applied Sciences 11, no. 16 (August 5, 2021): 7217. http://dx.doi.org/10.3390/app11167217.
Анотація:
Spatial Transformer Networks are considered a powerful algorithm to learn the main areas of an image, but still, they could be more efficient by receiving images with embedded expert knowledge. This paper aims to improve the performance of conventional Spatial Transformers when applied to Facial Expression Recognition. Based on the Spatial Transformers’ capacity of spatial manipulation within networks, we propose different extensions to these models where effective attentional regions are captured employing facial landmarks or facial visual saliency maps. This specific attentional information is then hardcoded to guide the Spatial Transformers to learn the spatial transformations that best fit the proposed regions for better recognition results. For this study, we use two datasets: AffectNet and FER-2013. For AffectNet, we achieve a 0.35% point absolute improvement relative to the traditional Spatial Transformer, whereas for FER-2013, our solution gets an increase of 1.49% when models are fine-tuned with the Affectnet pre-trained weights.
40
V Swathi, G., N. Paparao, and D. Swathi. "Design an Efficient Power Electronics Transformer (PET) for the Improvement of Quality in Power." International Journal of Engineering & Technology 7, no. 3.12 (July 20, 2018): 1046. http://dx.doi.org/10.14419/ijet.v7i3.12.17629.
Анотація:
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.
41
Pourakbari-Kasmaei, Mahdi, Farhan Mahmood, and Matti Lehtonen. "Optimized Protection of Pole-Mounted Distribution Transformers against Direct Lightning Strikes." Energies 13, no. 17 (August 24, 2020): 4372. http://dx.doi.org/10.3390/en13174372.
Анотація:
Direct lightning strikes on overhead phase conductors result in high overvoltage stress on the medium voltage (MV) terminals of pole-mounted transformers, which may cause considerable damage. Therefore, introducing an efficient protection strategy would be a remedy for alleviating such undesirable damages. This paper investigates the optimized protection of MV transformers against direct lightning strikes on the phase conductors. To this end, first, the impacts of grounding densities (number of grounded intermediate poles between every two successive transformer poles) on the probability of overvoltage stress on transformer terminals are investigated. Then, the implications of guy wire, as a supporting device for ungrounded intermediate poles, on reducing the overvoltage stress on transformers, are studied. Finally, the role of a surge arrester in mitigating the overvoltage stress of non-surge-arrester-protected transformer poles is scrutinized. The investigations are conducted on a sample MV network with 82 wood poles comprising 17 pole-mounted transformers protected by spark gaps. To provide in-depth analysis, two different poles, namely creosote- and arsenic-impregnated poles, are considered under wet and dry weather conditions. A sensitivity analysis is performed on grounding distances and on a combination of guy wire and grounded intermediate poles while taking into account soil ionization. The results provide a clear picture for the system operator in deciding how many grounded intermediate poles might be required for a system to reach the desired probabilities of transformers experiencing overvoltage stress and how the surge arrester and guy wires contribute to mitigating undesirable overvoltage stress.
42
Tu, Chia-Sheng, and Ming-Tang Tsai. "Optimal Phase Arrangement of Distribution Transformers for System Unbalance Improvement and Loss Reduction." Energies 13, no. 3 (January 22, 2020): 545. http://dx.doi.org/10.3390/en13030545.
Анотація:
This paper presents an efficient strategy for transformer planning to reduce the system losses by means of transformer rearrangement. The customer connected to the distribution transformer are first investigated by the field survey, and the loads of the various customers are collected from the customer information system (CIS) and distribution database system (DAS) to derive their load patterns. The objective function is to minimize the total line loss in the 24 intervals. An improved bacterial foraging algorithm (IBFO) is proposed herein to find the optimal phase combination of distribution transformers to minimize the total line loss by considering operating constraints. A three-phase load flow program with Eeuivalent current injection (ECT) is used to solve the total line loss and system unbalance factor on a Taipower distribution system. The results can help operators not only perform the proper installation phase selection of distribution transformers, but also reduce the system losses, decrease the system unbalance factor, and improve the voltage profiles of the buses.
43
Maximov, Serguei, Manuel A. Corona-Sánchez, Juan C. Olivares-Galvan, Enrique Melgoza-Vazquez, Rafael Escarela-Perez, and Victor M. Jimenez-Mondragon. "Mathematical Calculation of Stray Losses in Transformer Tanks with a Stainless Steel Insert." Mathematics 9, no. 2 (January 18, 2021): 184. http://dx.doi.org/10.3390/math9020184.
Анотація:
At present it is claimed that all electrical energy systems operate with high values of efficiency and reliability. In electric power systems (EPS), electrical power and distribution transformers are responsible for transferring the electrical energy from power stations up to the load centers. Consequently, it is mandatory to design transformers that possess the highest efficiency and reliability possible. Considerable power losses and hotspots may exist in the bushing region of a transformer, where conductors pass through the tank. Most transformer tanks are made of low-carbon steel, for economical reasons, causing the induction of high eddy currents in the bushing regions. Using a non-magnetic insert in the transformer tank can reduce the eddy currents in the region and as a consequence avoid overheating. In this work, analytical formulations were developed to calculate the magnetic field distribution and the stray losses in the transformer region where bushings are mounted, considering a stainless steel insert (SSI) in the transformer tank. Previously, this problem had only been tackled with numerical models. Several cases were analyzed considering different non-magnetic insert sizes. Additionally, a numerical study using a two dimensional (2D) finite element (FE) axisymmetric model was carried out in order to validate the analytical results. The solved cases show a great concordance between models, obtaining relative errors between the solutions of less than two percent.
44
Zhou, Li, Tongqin Shi, Songquan Huang, Fangchao Ke, Zhenxi Huang, Zhaoyang Zhang, and Jinzheng Liang. "Convolutional neural network for real-time main transformer detection." Journal of Physics: Conference Series 2229, no. 1 (March 1, 2022): 012021. http://dx.doi.org/10.1088/1742-6596/2229/1/012021.
Анотація:
Abstract For substation constructions, the main transformer is the dominant electrical equipment, and its arrival and operation affect the progress of project directly. In the context of smart grid construction, in order to improve the efficiency of real-time main transformer detection, this paper proposes an identification and detection method based on the SSD algorithm. The SSD algorithm is able to extract the target device (such as main transformer) accurately and the Lenet algorithm module can analyse the features contained in the image. To improve the accuracy of the detection method, the image migration algorithm of VGG-Net is used to expand the negative samples of main transformers to improve the generalisation of the algorithm. Finally, the image set collected in the real substation projects is used for validation, and result shows that the method identifies main transformers more accurately, with high effectiveness and feasibility.
45
Melnikova, Olga, Alexandr Nazarychev, and Konstantin Suslov. "Enhancement of the Technique for Calculation and Assessment of the Condition of Major Insulation of Power Transformers." Energies 15, no. 4 (February 21, 2022): 1572. http://dx.doi.org/10.3390/en15041572.
Анотація:
The findings of the analysis of data on the accident rate of power transformers indicate that one of the main causes of their failures is a decrease in the dielectric strength of the insulation. To reduce failures and extend the service life of power transformers in operation, the issue of enhancing the techniques for assessing the condition of their internal insulation becomes relevant. Currently, when selecting the major insulation of transformers, one takes into account the dependency of the dielectric strength of the oil passage on its width. Experts discuss the issues involved in the choice of major insulation while taking into account the effect of the generalized factor being the volume of the oil passage. The solution to that problem largely depends on the study of the statistical characteristics of the dielectric strength of oil passages of different volumes and the effect rated parameters of transformers have on them. The efficiency of the application of such diagnostic characteristics depends on the extent of studies available on them and the establishment of their standardized parameters. The paper proposes a method for estimating the change in the transformer oil volume in stressed oil passages of major insulation of high-voltage power transformers and statistical characteristics of the dielectric strength of these passages while taking into account the effect of the rated values of capacity and voltage of transformers. It is shown that the degree of effect of transformer technical parameters on the statistical characteristics of the dielectric strength of oil passages depends on the quality of transformer oil, which undergoes a change in operating conditions.
46
Chang, Wen-Ching, and Cheng-Chien Kuo. "A Novel Excitation Approach for Power Transformer Simulation Based on Finite Element Analysis." Applied Sciences 11, no. 21 (November 3, 2021): 10334. http://dx.doi.org/10.3390/app112110334.
Анотація:
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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Ravikumar, V., S. Ranjith, and T. Bhavyasree. "Automatic Load Sharing of Distribution Transformers to Reduce Over all Losses in Distribution network." E3S Web of Conferences 309 (2021): 01126. http://dx.doi.org/10.1051/e3sconf/202130901126.
Анотація:
An increase in the development of Industries and rapid growth in the population has led to an increase in the power demand in the distribution network. With these increased needs, the existing distribution transformer have become overloaded conditions. Due to overload on the transformer, the efficiency and power factor drops and also it led to increase in the transformer voltage regulation and windings get overheated. This paper presents a novel topology called transformer auto stop-start that will automatically energise and de-energise, one pair of transformers at a kV/V Distribution network. In this way, the proposed technique reduces overall electric losses. Performance of transformer under different load conditions are illustrated by simulation.
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Malažinskas, Vilius, Renaldas Raišutis, Alfonsas Morkvėnas, Saulius Gudžius, Audrius Jonaitis, Jonas Vaičys, and Gediminas Daukšys. "EVALUATION OF THE INSULATION CONDITION OF HIGH-VOLTAGE TRANSFORMERS BY DETECTING PARTIAL DISCHARGES USING THE ELECTROMAGNETIC WAVE RADIATION METHOD." Materiali in tehnologije 55, no. 2 (April 15, 2021): 253–61. http://dx.doi.org/10.17222/mit.2020.175.
Анотація:
High-voltage transformers are among the most important elements in an electric-power system. Each one of them is affected by various external factors: overvoltage, partial discharge (PD), overheating, vibrations, etc., which are created by a strong electric field, thermal effect, humidity, impurities, factory defects, dissolved water and gas in oil-type-transformer insulation. These and other factors, caused by the environment, reduce the life of a device. Thus, the evaluation of the device condition is one of the most important factors for a system-safety evaluation, which ensures a reliable and economical electrical-network operation. This work reviews different contact and non-contact methods, used to evaluate the conditions of transformers by measuring the level of PD. The selected method, i.e., the non-contact measurement of electromagnetic-wave radiation was used to evaluate the voltage-transformer status. The experiment was performed at a 110 kV substation. The authors discuss the efficiency of the selected method to evaluate the voltage-transformer insulation condition.
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Cremasco, Andrea, Wei Wu, Andreas Blaszczyk, and Bogdan Cranganu-Cretu. "Network modelling of dry-type transformer cooling systems." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 37, no. 3 (May 8, 2018): 1039–53. http://dx.doi.org/10.1108/compel-12-2016-0534.
Анотація:
Purpose The application of dry-type transformers is growing in the market because the technology is non-flammable, safer and environmentally friendly. However, the unit dimensions are normally larger and material costs become higher, as no oil is present for dielectric insulation or cooling. At designing stage, a transformer thermal model used for predicting temperature rise is fundamental and the modelling of cooling system is particularly important. This paper aims to describe a thermal model used to compute dry transformers with different cooling system configurations. Design/methodology/approach The paper introduces a fast-calculating thermal and pressure network model for dry-transformer cooling systems, preliminarily verified by analytical methods and advanced CFD simulations, and finally validated with experimental results. Findings This paper provides an overview of the network model of dry-transformer cooling system, describing its topology and its main variants including natural or forced ventilation, with or without cooling duct in the core, enclosure with roof and floor ventilation openings and air barriers. Finally, it presents a formulation for the new heat exchanger element. Originality/value The network approach presented in this paper allows to model efficiently the cooling system of dry-type transformers. This model is based on physical principles rather than empirical assessments that are valid only for specific transformer technologies. In comparison with CFD simulation approach, the network model runs much faster and the accuracies still fall in acceptable range; therefore, one is able to utilize this method in optimization procedures included in transformer design systems.
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Pham, Khoi Dinh Anh. "Measurement -based electrical parameters of power transformers for Frequency Response Analysis interpretation - Part I: Core analysis." Science and Technology Development Journal 20, K3 (June 30, 2017): 5–10. http://dx.doi.org/10.32508/stdj.v20ik3.1074.
Анотація:
Although the standard Frequency Response Analysis (FRA) test has been approved as an efficient tool to diagnose mechanical failures in power transformers, the demand to interpret FRA traces in practical and physical way is still requested. That means physical electrical parameters of transformers should be determined reasonably based on real measurements and afterwards are applicable for the interpretation. For purpose of FRA interpretation in practical manner, electrical parameters of power transformers in a physical equivalent circuit should be determined. As a first step, the paper introduces a new approach in determining frequency dependent core impedances of a distribution transformer based on the combination of circuit analysis of a duality-based model, measurements of driving-point impedances and experimental formulas. From that, two important contributions can be drawn. Firstly, frequency dependent core impedances are ready as available components in the circuit for FRA interpretation in broad frequency range. Secondly, the core parameters could be useful indicators for detecting relevant failures in cases there is no more failure on transformer windings.