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1
Oktavianus Rikardus Waro e Aris Heriandriawan. "Analisis Umur Pakai Transformator Distribusi 800 Dan 1600 kVA Di PDAM Ngagel Surabaya". Venus: Jurnal Publikasi Rumpun Ilmu Teknik 2, n. 2 (9 marzo 2024): 01–17. http://dx.doi.org/10.61132/venus.v2i2.234.
Testo completoAbstract (sommario):
Distribution transformers have a very important role in the electric power system. The lifespan of transformers in electric power systems will decrease over time. The reduced service life of distribution transformers is caused by several factors, including loading, ambient temperature, transformer winding temperature and transformer oil temperature. The author uses quantitative and qualitative research types. This research was conducted to determine the remaining useful life of distribution transformers. The data used in this research are transformer template data and peak load data during the day and night. The results of data processing obtained state that the first transformer's estimated remaining life with a load > 80% is 18 years starting from 2023, the second transformer's estimated remaining life with a load > 80% is 16 years starting from 2023, for the third and fourth transformers it is not calculated because it has been used since 1982 or is around 41 years old. For the winding temperature on the first transformer LBP 84 ℃ and BP 89 ℃, on the second transformer the winding temperature LBP 81 ℃ and BP 96 ℃. Both transformers are still considered good because the hot spot temperature is below the maximum limit set by the IEEE in 1955, namely a temperature of 98 ℃.
2
ÖZÜPAK, Yıldırım. "Medium Frequency Electric Field Analysis of Power Transformers in High Voltage System". BEN Vol:2 Issue:3 2021 2, n. 3 (8 febbraio 2021): 1–5. http://dx.doi.org/10.36937/ben.2021.003.001.
Testo completoAbstract (sommario):
Electronic power transformers (EPT) are transformers that are smaller in size and volume compared to conventional 50 Hz frequency transformers. Medium frequency transformers (MFT) have begun to become important components in high voltage and high power energy conversion systems such as EPTs. In this study, the electric field distribution of these transformers is discussed. The electric field distributions in the transformer have been obtained using the two-dimensional finite element method (FEM). Besides, maximum electric field intensities were obtained in the study. ANSYS@Maxwell simulation program, which realizes a solution based on FEM, was used for these analyzes. Electromagnetic field analyzes of the same transformer under normal conditions were also performed to compare the analyzes. Besides, the values obtained from the high-frequency analysis, the values obtained from the study below 50 Hz frequency, and the values obtained experimentally were compared. In this way, the stress in the insulation material of the transformer and the weak parts of the insulation material were detected. It is expected that the method used will contribute to future studies to examine the results of the electric field distribution analysis of transformers.
3
Savchenko, Oleg Vladislavovich, Mihail Yur'evich Khmel, Valery Nikolaevich Polovinkin e Igor Mihaylovich Kalinin. "Ship electric propulsion systems transformers: specific aspects of development". Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2024, n. 1 (29 febbraio 2024): 112–20. http://dx.doi.org/10.24143/2073-1574-2024-1-112-120.
Testo completoAbstract (sommario):
The necessity of new organizational and technical solutions in shipbuilding to ensure the quality of marine transformer transformers is substantiated. The analysis of the requirements of the Russian Maritime Register of Shipping, the current ISS for dry transformers is carried out, the experience of enterprises of related industries and foreign companies, the design features of power transformers of the ship's electric propulsion system are considered. The results of the analysis of the requirements for power transformers of marine electric propulsion systems, the features of their design and operation are presented. The main parameters of the converters in operating and emergency modes are considered and analyzed. The organizational and technical directions of ensuring increased reliability of marine converter transformers are proposed. Unlike converter transformers for land transport, there are no regulatory documents for power converter transformers in shipbuilding. The regulatory documents in force in shipbuilding do not fully take into account the specifics of marine conversion transformers. The existing main features of marine converter transformers are noted. High economic losses in the event of an accident of marine converter transformers determine higher requirements for their electrodynamic stability compared with converter transformers for land transport. In shipbuilding, there are no requirements for determining the partial short-circuit voltage and the splitting short-circuit voltage during testing of transformers necessary for the analysis of their characteristics and modes. When creating marine converter transformers, it is necessary to justify the characteristic modes of marine transformers using computer modeling, develop methods for measuring and calculating the parameters of selected modes and perform process calculations for the most likely accidents in the transformer – rectifier system. With the increase in the power of shipboard electric propulsion systems, the development of state regulatory documentation to ensure the quality of development and operation of converter transformers is becoming increasingly relevant.
4
Xia, Lingyu, Xixiu Wu, Hui Hou, Shipu Wu, Yunbing Peng e Jiaxin Cao. "Study on the error characteristics of transformer for primary and secondary fusion used in pole-mounted switchgear". Journal of Physics: Conference Series 2757, n. 1 (1 maggio 2024): 012014. http://dx.doi.org/10.1088/1742-6596/2757/1/012014.
Testo completoAbstract (sommario):
Abstract The fusion of primary and secondary functions refers to integrating the function of primary equipment and secondary equipment together. If doing so, the working condition of the equipment for primary and secondary fusion becomes more and more complex and bad, especially the transformer working in the smaller workspace after fusing. Therefore, this paper focuses on the transformer used in primary and secondary fusion pole-mounted Switchgear and establishes the temperature field and electric field simulation model of the primary and secondary fusion pole-mounted switchgear transformer, respectively, and the temperature rise and the environment electric field interference influencing the error of transformer are analyzed as well. When the working environment temperature ranges from -40 to 70°C, the maximum error of low-power current transformers and resistive voltage transformers is 0.1246% and 0.0371%, respectively. The electric field is one of the main factors influencing resistive voltage transformers, which makes ratio errors and angle errors -0.256% and -22.5392’, respectively. The research reveals that under conditions, the error is mainly dependent on temperature rise and electric field. These two factors have a great influence on the error, while the transformers still have enough reliability.
5
Yusupov, D. T., I. K. Ismoilov, A. E. Norboev, R. X. Beytullaeva e A. A. Yuldashev. "Development of a simulation model for assessing the technical condition of oil power transformers by measuring vibroacoustic parameters". E3S Web of Conferences 510 (2024): 04014. http://dx.doi.org/10.1051/e3sconf/202451004014.
Testo completoAbstract (sommario):
In the electric power industry, oil-type power transformers are considered the main device that ensures reliable transmission of electric power, and their technical capabilities are analyzed. Factors affecting long-term reliable operation of oil-fired power transformers are investigated. In this paper, a simulation model is developed to assess the condition of oil power transformers during rapid diagnosis. A mathematical model has also been developed that allows calculating the absorption coefficients and the general technical condition of oil power transformers depending on the value of the input variables of oil power transformers operating in city power networks. The authors developed a Simulink model for rapid assessment of the technical condition of the oil power transformer. A block diagram is created that allows to determine the value of the technical condition of the oil power transformer according to the vibroacoustic parameters.
6
Ilyas, Iriandi, e Muhamad Taufan Agassy. "ANALISIS KEGAGALAN CURRENT TRANSFORMER (CT) TIPE DUA BELITAN SEKUNDER DENGAN INTI MAGNETIK TERPISAH PADA SISTEM PROTEKSI DAN PEMBATAS DAYA". SAINSTECH: JURNAL PENELITIAN DAN PENGKAJIAN SAINS DAN TEKNOLOGI 32, n. 1 (29 marzo 2022): 41–48. http://dx.doi.org/10.37277/stch.v32i1.1240.
Testo completoAbstract (sommario):
ABSTRACT
Current transformers function to transform large currents into small currents used for electrical energy measurement instruments, power limitation and protection of electric power networks, current transformers have many types, the use of current transformers in actual facts such as electrical power requested by consumers to producers of electricity providers at 53 kVA to 197 kVA using a single ratio current transformer type and> 197 kVA using a secondary twisting transformer type with a separate magnetic core In this type of current transformers with different ratios have different saturation values also due to high interference current values, so they are not able to provide an accurate secondary current value according to the class and the ability of current transformers against measuring instruments, power limitation and protection of electric power networksBy analyzing the failure of these types can be a reference or reference in the use of current transformers by selecting the appropriate type, ratio and accuracy class on the electricity network
7
Alyunov, A. N., O. S. Vyatkina, I. G. Akhmetova, R. D. Pentiuc e K. E. Sakipov. "Issues on optimization of operating modes of power transformers". E3S Web of Conferences 124 (2019): 02015. http://dx.doi.org/10.1051/e3sconf/201912402015.
Testo completoAbstract (sommario):
The article presents measure to optimize the operating modes of power transformers in order to minimize losses of electrical energy. The influence of actual voltage and service life of power transformers on electric power losses is shown. It was proposed to determine the economic capacity of power transformers taking into account the indicated factors, as well as taking into account the time of transformer switching on into the electric network and the form of the load schedule.
8
Jin, Lan, Dowon Kim, Ahmed Abu-Siada e Shantanu Kumar. "Oil-Immersed Power Transformer Condition Monitoring Methodologies: A Review". Energies 15, n. 9 (6 maggio 2022): 3379. http://dx.doi.org/10.3390/en15093379.
Testo completoAbstract (sommario):
A power transformer is one of the most critical and expensive assets in electric power systems. Failure of a power transformer would not only result in a downtime to the entire transmission and distribution networks but may also cause personnel and environmental hazards due to oil leak and fire. Hence, to enhance a transformer’s reliability and extend its lifespan, a cost-effective and reliable condition monitoring technique should be adopted from day one of its installation. This will help detect incipient faults, extend a transformer’s operational life, and avoid potential consequences. With the global trend to establish digital substation automation systems, transformer online condition monitoring has been given much attention by utilities and researchers alike. Several online and offline condition monitoring techniques have been recently proposed for oil-immersed power transformers. This paper is aimed at providing a state-of-the-art review for the various condition monitoring technologies used for oil-immersed power transformers. Concept of measurements and analysis of the results along with the future trend of condition monitoring techniques are presented.
9
Novais, I. F., A. A. P. Junior e S. F. P. Silva. "Modeling Three-Phase Transformers". Energies and Quality Journal 1 (giugno 2019): 60–65. http://dx.doi.org/10.24084/eqj19.233.
Testo completoAbstract (sommario):
Transformers in electric power systems are of great importance, with significant effects on the distribution of electric energy. The modeling of this machine, considering the various usable connections, requires a more detailed analysis for better results. Thus, the objective of this work is to propose a three-phase transformer model including the neutral in the admittance matrices, the ground impedance, taps settings and also the magnetizing branch. Key words Three-phase transformers modeling, ground impedance, magnetizing branch, admittance matrix
10
Jain, Akansha, e Masoud Karimi-Ghartemani. "Mitigating Adverse Impacts of Increased Electric Vehicle Charging on Distribution Transformers". Energies 15, n. 23 (29 novembre 2022): 9023. http://dx.doi.org/10.3390/en15239023.
Testo completoAbstract (sommario):
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.
11
DeCristofaro, Nicholas. "Links of Science & Technology". MRS Bulletin 23, n. 5 (maggio 1998): 50–56. http://dx.doi.org/10.1557/s0883769400030451.
Testo completoAbstract (sommario):
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.
12
Su, Biao, Li Xue Li, Yi Hui Zheng, Xin Wang, Yan Liu e Chang Li Dang. "Design and Analysis of PCB Rogowski Coil Current Transformer". Applied Mechanics and Materials 672-674 (ottobre 2014): 984–88. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.984.
Testo completoAbstract (sommario):
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.
13
Hanus, Oleksii, e Kostiantyn Starkov. "STUDY OF THE NATURE OF OVERVOLTAGES IN THE ELECTRICAL NETWORK ARISING FROM VOLTAGE TRANSFORMERS". Bulletin of the National Technical University "KhPI". Series: Energy: Reliability and Energy Efficiency, n. 1 (2) (2 luglio 2021): 28–36. http://dx.doi.org/10.20998/2224-0349.2021.01.05.
Testo completoAbstract (sommario):
A non-linear dynamic mathematical model of voltage transformer has been considered and overvoltages arising on the elements of voltage transformer equivalent circuit during transient processes have been investigated. The influence of voltage transformer secondary circuit capacitance on overvoltage multiplicity in the primary circuits and the duration of transients has been determined. The advantages of approximation of nonlinearity of voltage transformers by hyperbolic sine are used. Mathematical expressions determining the nature of changes in the forced and free components of the transient process in an electrical network with a voltage transformer have been obtained. It is shown that with the increase of the electric network capacitance the duration of the transition process damping increases and the frequency of the forced oscillations and the level of overvoltage decrease. It is proved that even small, in comparison with the primary nominal sinusoidal voltage, aperiodic components of the voltage transient process can lead to significant overvoltages during voltage transformer outages. It has been substantiated that both the secondary resistance and the switching torque influence the overvoltage multiplicity arising in the primary winding of voltage transformers. It is shown that the closed secondary winding worsens the disconnection process of non-linear inductance of voltage transformers. The values to which overvoltages increase in this case are determined. According to the results of calculations it is determined that with open secondary winding of voltage transformers the duration of transient process significantly increases. It has been found that the decrease of frequency of forced oscillations, which occurs in this case, is accompanied by an increase of currents in the primary winding of the voltage transformer, which is dangerous in terms of thermal stability of the winding insulation. It is shown, that closing the secondary winding of voltage transformers leads to significant reduction of transient damping time. It is suggested that this algorithm can be used to provide a rapid breakdown (suppression) of ferroresonant processes. The effectiveness of such a measure of stopping of ferroresonance processes as short-term shunting of secondary winding of voltage transformers has been investigated. The correlation of parameters of electric networks (capacity of busbar sections, nonlinearity of characteristics of voltage transformers, disconnection torque, etc.) at which ferroresonance process may occur and consideration of which may allow, in terms of prevention of ferroresonance processes, to identify substations (electric networks) that require more detailed research has been determined. The results of analytical studies were tested in the electric networks of JSC "Kharkivoblenergo" and used in the electricity distribution system for the selection of specific voltage transformers for certain configurations of electrical networks.
14
Sharma, Asmita. "Solid State Transformer: An Overview of Application and Advantages". International Journal for Research in Applied Science and Engineering Technology 12, n. 7 (31 luglio 2024): 335–37. http://dx.doi.org/10.22214/ijraset.2024.63557.
Testo completoAbstract (sommario):
Abstract: Solid-state transformer (SST), Electronic power transformer or Power electronic transformer (PET) contain the transformer inside the AC-TO-AC converters or DC-TO-DC converters. SST is type of electric power converter that replaces a conventational transformer used in electric power distribution.SST carries the full power and provides the electrical isolation. This paper gives the information of the solid state transformers advantages and applications
15
Kuznetsov, Andrey Albertovich, Viktor Vasilyevich Kharlamov e Mariya Andreevna Volchanina. "Increase of efficiency of insulation diagnostics for high-voltage bushing of three-phase transformers". Transport of the Urals, n. 3 (2022): 86–93. http://dx.doi.org/10.20291/1815-9400-2022-3-86-93.
Testo completoAbstract (sommario):
The paper considers technical means of methods for diagnostics of insulation of high-voltage bushing for power transformers. It also points out advantages and disadvantages of existing methods and proposes a new solution for contactless diagnostics on the basis of measurement of electric field parameters near the surface of bushing. For control of technical condition of power transformers bushing the authors have developed a scheme for placement of elements of portable diagnostics device. A defect in the insulator leads to redistribution of electric potentials on capacitive elements of the high-voltage bushing and to change of electric field intensity around the fault bushing. The proposed design allows fast mounting of device on the power transformer body without its shutdown and revealing of fault bushing according to change of field intensity (sensors of electric field are located near bushing). The developed method for diagnostics of condition of power transformers bushing based on analysis of data of electric field distribution allows determining technical condition of bushing in operation conditions.
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Melnikova, O. S., e V. S. Kuznetsov. "Method of calculating the electric strength of oil channels of the main insulation of power transformers". Vestnik IGEU, n. 5 (30 dicembre 2020): 48–55. http://dx.doi.org/10.17588/2072-2672.2020.5.048-055.
Testo completoAbstract (sommario):
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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Kulesz, Barbara. "RECTIFIER TRANSFORMERS IN ELECTRIC TRACTION SUBSTATIONS ‐ DIFFERENT DESIGNS". TRANSPORT 20, n. 2 (20 aprile 2005): 66–72. http://dx.doi.org/10.3846/16484142.2005.9637998.
Testo completoAbstract (sommario):
Electric traction in Poland is supplied with dc voltage which is obtained from the power grid via traction substations equipped with transformers and rectifiers. The paper gives the results of the investigation of different designs of these transformer‐rectfier sets ‐ namely, 12‐ and 24‐pulse systems. The comparison of electrical quantities such as ripple content, harmonic content of supply current and output voltage and utilisation of transformer secondary windings is provided.
18
Krasovskyi, Pavlo. "Dynamics of No-Load Losses in Power Transformers". Advanced Engineering Forum 25 (novembre 2017): 113–17. http://dx.doi.org/10.4028/www.scientific.net/aef.25.113.
Testo completoAbstract (sommario):
Developed and released recommendations to clarify the calculation of idle power losses in power transformers of distribution networks. It takes into account the dynamics of magnetic properties changes in transformer cores, depending on the operation term and conditions, and major overhaul of the transformers with the magnetic core unburdening. It will improve the accuracy of normative losses calculation in power transformers and determine the most accurate structure of losses in electric networks.
19
Tian, Fenglan, Zhongzhao Jing, Huan Zhao, Enze Zhang e Jiefeng Liu. "A Synthetic Condition Assessment Model for Power Transformers Using the Fuzzy Evidence Fusion Method". Energies 12, n. 5 (5 marzo 2019): 857. http://dx.doi.org/10.3390/en12050857.
Testo completoAbstract (sommario):
Condition-based maintenance decision-making of transformers is essential to electric enterprises for avoiding financial losses. However, precise transformer condition assessment was tough to accomplish because of the negligence of the influence of bushing and accessories, the difficulty of fuzzy grade division, and the lack of reasonable fuzzy evidence fusion method. To solve these problems, a transformer assessing model was proposed in the paper. At first, an index assessing system, considering the main body, the bushing and the accessories components, was established on the basis of components division of transformers. Then, a Cauchy membership function was employed for fuzzy grades division. Finally, a fuzzy evidence fusion method was represented to handle the fuzzy evidences fusion processes. Case studies and the comparison analysis with other methods were performed to prove the effectiveness of this model. The research results confirm that the proposed model could be recommendation for condition based maintenance of power transformers for electric enterprises.
20
Son, Won-Jin, e Byoung Kuk Lee. "Design of Planar Transformers for LLC Converters in High Power Density On-Board Chargers for Electric Vehicles". Energies 16, n. 18 (21 settembre 2023): 6757. http://dx.doi.org/10.3390/en16186757.
Testo completoAbstract (sommario):
This article presents a planar transformer design and optimization method for high power density on-board chargers (OBCs) utilized in electric vehicles (EVs). Owing to considerations of electrical safety, OBCs require an isolated converter, leading to a substantial increase in volume due to the inclusion of a transformer. To address this issue and achieve high power density, a planar transformer is used, and an optimized design method is proposed for pattern arrangement, width, and core shape. The feasibility of the design is verified through the development of a 3.3 kW OBC prototype. Consequently, when compared to conventional transformers, the design method in this article results in a 27% reduction in the transformer’s height and a 20% reduction in its overall volume. This reduction is advantageous for meeting the requirements of high power density OBCs.
21
Disios, Konstantinos, Irodotos Mantas, Antonios Melanitis, Eleftherios Amoiralis e Marina Tsili. "Electric Machine Design through Investigation of Thermal Performance by Installing Thermocouple Sensors". Materials Science Forum 856 (maggio 2016): 349–55. http://dx.doi.org/10.4028/www.scientific.net/msf.856.349.
Testo completoAbstract (sommario):
The aim of this paper is to explore new approaches of monitoring, diagnosis, condition evaluation, and possibility of extending the life of transformers. Research, emphasizing to experimental work, is conducted on a 1.5 KVA single-phase transformer to measure the internal temperature of the primary and secondary winding, using reliable instruments. Special consideration is given to the convenience in the acquisition and management of experimental data, so that the proposed monitoring system can be exploited for all kinds of thermal tests and various loading conditions. The transformer under study is designed and constructed from scratch, according to particular technical specifications. Having completed the transformer construction with the temperature sensors linked in each coil, our aim is to apply various types of loads and record the temperature variation inside the transformer. A process of acquisition and processing of data related to various parameters of transformers is developed so as to predict the behavior and prevent the failure of a transformer.
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Kefalas, Themistoklis D., e Antonios Kladas. "Reduction of Power Grid Losses by Using Energy Efficient Distribution Transformers". Materials Science Forum 721 (giugno 2012): 269–74. http://dx.doi.org/10.4028/www.scientific.net/msf.721.269.
Testo completoAbstract (sommario):
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.
23
Nozdrenkov, V. S., I. M. Diahovchenko, M. V. Petrovskyi e V. V. Volokhin. "Fuzzy model of compensation for aging factors of distribution transformers". Electrical Engineering and Power Engineering, n. 2 (27 giugno 2024): 7–17. http://dx.doi.org/10.15588/1607-6761-2024-2-1.
Testo completoAbstract (sommario):
Purpose. This paper aims to evaluate the negative factors that affect the aging of power distribution transformers, develop a fuzzy control model for their compensation, and study the results of applying the proposed model to different modes of the electrical power network. Methodology. The mathematical method of fuzzy logic was used to implement the control system of the power grid operating modes. Findings. The article presents a structure based on fuzzy logic for compensating depreciation factors of distribution transformers. A tuning algorithm and measures were developed to optimize the transformer's load level and power factor. The developed model analyzes the parameters and factors affecting the normal operation of the transformer and warns of dangerous factors that threaten reliability and may lead to a malfunction. In addition, the efficiency of PV generating stations, shunt capacitor banks, and energy storage systems installed on the secondary voltage side to preserve the service life of distribution transformers was analyzed and discussed. Originality. The paper further develops the fuzzy logic models used to optimize the operation of the power grid and compensate for the aging factors of power distribution transformers Practical value. The results obtained in the paper can be used to build an optimal system for controlling the operation modes of the electric power grid, which reduces the factors that accelerate the aging of power distribution transformers.
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Gilfanov, K. H., N. Tien, R. N. Gaynullin e 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.
Testo completoAbstract (sommario):
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.
25
Varga, Aleksandr A., e Galaktion V. Shvedov. "Estimating the Error of Calculating the Load Losses in 6—10 kV Distribution Electric Networks". Vestnik MEI, n. 5 (2021): 37–43. http://dx.doi.org/10.24160/1993-6982-2021-5-37-43.
Testo completoAbstract (sommario):
The aim of the study is to estimate the level of load losses for actual (nonuniform) loading of transformer substations in comparison with the load loss level under the conditions of their being uniformly loaded for a typical 6 kV urban distribution electric network. The extent to which such networks are equipped with automated information and measurement systems for fiscal electricity metering is extremely poor. Therefore, not only the load curves of the 6--10/0.4 kV substation transformers, but also their load factors are unknown in the majority of cases. Under these conditions, in calculating the load losses in 6--10 kV distribution electric networks, it is assumed that all substation transformers are uniformly (equally) loaded. The load losses in these electrical networks are calculated with a certain error associated with the assumption according to which the substation transformers are supposed to be uniformly loaded. Under these conditions, estimation of this error becomes of issue. The article describes the modeling, calculation and analysis of technical losses of electricity under the conditions of nonuniformly loaded transformers of a typical urban distribution network consisting of four transformers and four cables interconnecting them. The modeling and calculation of power losses were carried out using the RAP-10-st computer program for several different groups of transformer loading factors. Within each group, different subgroups were produced by rearranging the group loading factors. Each subgroup modeled a nonuniform transformers loading mode in the studied network. For each of these modes, the power losses were calculated and studied with the use of the RAP-10-st computer program. A conclusion has been drawn from the obtained analysis results regarding the error in determining the load losses associated with the assumption about the uniform loading of the substation transformers in the network. The obtained results may prompt electric grid companies to increase the extent of fitting their networks with automated information and measurement systems for fiscal electricity metering to improve the accuracy of determining the load losses.
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S, Kumaran. "Transformer Fault Condition Prognosis Using Vibration Signals Over Cloud Environment". International Scientific Journal of Engineering and Management 03, n. 04 (23 aprile 2024): 1–9. http://dx.doi.org/10.55041/isjem01631.
Testo completoAbstract (sommario):
he Automatic Area Transformer Fault Message Indicator is an innovative system designed to detect and report faults in transformers. It utilizes potential and current transformers, precision rectifiers, and sensors to monitor high/low voltage, current, frequency, and transformer temperature. The data is processed by a microcontroller, displayed on an LCD, and transmitted to the electric utility station via GSM, enabling timely identification and communication of transformer issues for efficient maintenance and grid reliability. This system offers several key benefits. First, its use of advanced sensors and precision rectifiers ensures accurate measurement of critical parameters, allowing for early detection of potential faults. Keywords—GSM, Step down transformer, potential and current transformer, Temperature sensor.
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Saidane, A. "Electric Machinery and Transformers". Microelectronics Journal 32, n. 9 (settembre 2001): 787. http://dx.doi.org/10.1016/s0026-2692(01)00052-0.
Testo completo
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Naumov, I. V., D. N. Karamov, A. N. Tretyakov, M. A. Yakupova e E. S. Fedorinovа. "Study of power transformer loading in rural power supply systems". Safety and Reliability of Power Industry 13, n. 4 (18 febbraio 2021): 282–89. http://dx.doi.org/10.24223/1999-5555-2020-13-4-282-289.
Testo completoAbstract (sommario):
The purpose of this study is to study the effect of loading power transformers (PT) in their continuous use on their energy efficiency on a real-life example of existing rural electric networks. It is noted that the vast majority of PT in rural areas have a very low load factor, which leads to an increase in specific losses of electric energy when this is transmitted to various consumers. It is planned to optimize the existing synchronized power supply systems in rural areas by creating new power supply projects in such a way as to integrate existing power sources and ensure the most efficient loading of power transformers for the subsequent transfer of these systems to isolated ones that receive power from distributed generation facilities. As an example, we use data from an electric grid company on loading power transformers in one of the districts of the Irkutsk region. Issues related to the determination of electric energy losses in rural PT at different numerical values of their load factors are considered. A computing device was developed using modern programming tools in the MATLAB system, which has been used to calculate and plot the dependence of power losses in transformers of various capacities on the actual and recommended load factors, as well as the dependence of specific losses during the transit of 1 kVA of power through a power transformer at the actual, recommended and optimal load factors. The analysis of specific losses of electric energy at the actual, recommended and optimal load factors of PT is made. Based on the analysis, the intervals of optimal load factors for different rated power of PT of rural distribution electric networks are proposed. It is noted that to increase the energy efficiency of PT, it is necessary to reduce idling losses by increasing the load of these transformers, which can be achieved by reducing the number of transformers while changing the configuration of 0.38 kV distribution networks.
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HS, Syafruddin, Ali Hanafia Rambe e Agus Prabowo. "Impact Analysis of Public Electric Vehicle Charging Stations on Transformers and Distribution Networks". Journal of Mechanical, Civil and Industrial Engineering 4, n. 4 (25 ottobre 2023): 08–19. http://dx.doi.org/10.32996/jmcie.2023.4.4.2.
Testo completoAbstract (sommario):
Public Electric Vehicle Charging Stations (SPKLUs) are critical infrastructure in facilitating the increasingly popular use of electric vehicles. The increasing number of electric vehicles using SPKLU also has an impact on existing transformers and distribution networks. This research uses the Fluke 1748 tool to analyze the impact on transformers and distribution networks. The Fluke 1748 is a tool that can record and analyze electrical parameters such as voltage, current, power, and power factor with high precision. The method used in this analysis involves installing the Fluke 1748 device at strategic points around the SPKLU, transformer, and distribution network. The results of this study are At the public electric vehicle charging station, an analysis has been carried out on the voltage and current where the results of THDV of 2.212% still meet the IEEE 2014 standard and THDi of 4.929% meet the IEEE 2014 standard, the impact caused is that there are losses in kWh sales due to voltage drops or voltage drops of 2250 watts, losses in significant transformers and in the conductor also cause a voltage drop of 2.5% of the nominal voltage.
30
Levin, Vladimir M., e Ammar A. Yahya. "Adaptive management of technical condition of power transformers". International Journal of Electrical and Computer Engineering (IJECE) 10, n. 4 (1 agosto 2020): 3862. http://dx.doi.org/10.11591/ijece.v10i4.pp3862-3868.
Testo completoAbstract (sommario):
Ensuring reliable operation of power transformers as part of electric power facilities is assigned to the maintenance and repair system, whose important components are diagnostics and monitoring of the technical condition. Monitoring allows you to answer the question of whether the transformer abnormalities and how to do they manifest, while diagnostics allow determining the nature, the severity of the problem, determine the cause and possible consequences. The article presents the results of the authors ' research on creating an algorithm for adaptive control of the technical condition of power transformers using diagnostic and monitoring data. The developed algorithm implements the decision-making procedure for ensuring the reliable operation of oil-filled transformer equipment as part of the substations of electric power facilities. The decision-making procedure is based on the method of statistical Bayesian identification the states of a transformer based on the results of dissolved gas analysis (DGA) in oil. The method is characterized by high reliability of recognizing defects in the transformer and the ability to adapt the probabilities of the obtained solutions to the newly received diagnostic information. These results illustrate the effectiveness of the developed approach and the possibility of its application in the operation of oil-filled transformer equipment.
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Malažinskas, Vilius, Renaldas Raišutis, Alfonsas Morkvėnas, Saulius Gudžius, Audrius Jonaitis, Jonas Vaičys e 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, n. 2 (15 aprile 2021): 253–61. http://dx.doi.org/10.17222/mit.2020.175.
Testo completoAbstract (sommario):
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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Berg, Heinz-Peter, e Nicole Fritze. "Risk and Consequences of Transformer Explosions and Fires in Nuclear Power Plants / Ryzyko I Konsekwencje Wybuchów Transformatora I Pożarów W Elektrowniach Jądrowych". Journal of KONBiN 23, n. 1 (1 settembre 2012): 5–16. http://dx.doi.org/10.2478/jok-2013-0034.
Testo completoAbstract (sommario):
Abstract The high failure frequency and the resultant reliability and safety implications in recent years of transformers, in particular at nuclear power plants (NPP), required an in-depth assessment. Fires of main transformers are considered as critical because of the large quantity of oil in contact with high voltage elements. Therefore, these phenomena have been investigated in more detail using the information from the OECD FIRE database for NPP. 12.8 % of all fires and, thus, the most frequent fire source in this database are transformer fires, mainly fires of high voltage oil-filled transformers. Thus, possible diagnostic measures to avoid such events and enhance the reliability currently discussed in Germany are shortly described. Moreover, consequences of transformer failures with respect to a reliable electric power supply are addressed.
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Abdikulova, Z. K., e E. O. Zhaparov. "СALCULATION AND CHOICE OF ELECTRIC CHART OF SUBSTATION OF THE КENTAU TRANSFORMER PLANT". BULLETIN Series of Physics & Mathematical Sciences 70, n. 2 (30 giugno 2020): 141–48. http://dx.doi.org/10.51889/2020-2.1728-7901.21.
Testo completoAbstract (sommario):
Electric supply system in enterprises must provide with electrical supply continuity and reliability as in normal and accidental regimes, quality electro energetic, production efficiency, so in connection with these in the article there have been analyzed work regimes of substations, studied electrical net scheme for Kentau Transformer Plant’s substation, calculated plant’s loads and short circuit currents and on the base of the calculated results curried out inspection for the chosen equipment. The number of connections, reliability of power supply and prospects for development are the determining factors for choosing the electrical scheme of high-voltage switchgears. You also need to take into account the need to conduct audits and tests of switches without interruption. In our case, we have four connections: two communication lines with electrical systems and two transformers. The distribution devices of the substation of the Kentau transformer plant are connected to the transformers according to a block scheme. Electrical installations are connected to the network transformer unit or receive backup power from another substation, since in case of failure of one network, both transformers can not work with the rest of the network. Based on this, measures are proposed for the reconstruction of the substation, with the replacement of the block diagram of the switchgear with the circuit for connecting the power transformer to the switchgear by a bus bridge. Offered measurements on reconstruction of the substation by replacing block scheme of switchgears to scheme of power transformer connection with DD bus bridge. Worked out main modernization problems of the substation switchgear, done calculation and selection of distributing bus bars for arranging switchgear.
34
Seheda, M. S., P. F. Gogolyuk e Y. V. Blyznak. "High-frequency periodic processes in two-winding power transformers". Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, n. 6 (2021): 96–100. http://dx.doi.org/10.33271/nvngu/2021-6/096.
Testo completoAbstract (sommario):
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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Lansberg, A. A., A. V. Vinogradov e 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, n. 5 (9 gennaio 2022): 34–45. http://dx.doi.org/10.30724/1998-9903-2021-23-5-34-45.
Testo completoAbstract (sommario):
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».
36
Bolshanin, G. A., e E. G. Skulina. "USE OF TRANSFORMERS AS PAIRING DEVICES FOR MEASURING SYSTEMS". EurasianUnionScientists 1, n. 7(76) (20 agosto 2020): 66–70. http://dx.doi.org/10.31618/esu.2413-9335.2020.1.76.895.
Testo completoAbstract (sommario):
The execution of devices of interface of means of control of indicators of quality of electric energy with the electric power system in the form of measuring transformers of voltage and shunt of alternating current is shown. This is most preferable due to the lack of non-linearity in the working area of magnetic characteristics. A transformer substitution scheme is shown, as well as experiment execution schemes, as a result of which the necessary parameters are determined.
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Alame, Dima, Maher Azzouz e Narayan Kar. "Assessing and Mitigating Impacts of Electric Vehicle Harmonic Currents on Distribution Systems". Energies 13, n. 12 (23 giugno 2020): 3257. http://dx.doi.org/10.3390/en13123257.
Testo completoAbstract (sommario):
Harmonic currents of electric vehicle (EV) chargers could jeopardize the power quality of distribution systems and add to the transformer’s losses, thus degrading its lifetime. This paper assesses and mitigates the impacts of different EV chargers on distribution transformers and the voltage quality of distribution systems. The effect of state-of-charge (SOC) of the EV battery is considered through applying weighted arithmetic mean to accurately assess the impacts of EV harmonic currents on aging and losses of the EV interfacing transformer. The voltage quality of the IEEE 33-bus distribution system, supplying several EV parking lots, is also assessed at different charging levels using a fast-decoupled harmonic power flow. A new optimal harmonic power flow algorithm—that incorporates photovoltaic-based distribution generation units (DGs)—is developed to enhance the voltage quality of distribution systems, and elongate the lifetime of the substation transformer. The effectiveness of the proposed mitigation method is confirmed using the IEEE 33-bus distribution system, hosting several EV charging stations and photovoltaic-based DGs.
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Carreno, Alvaro, Marcelo Perez, Carlos Baier, Alex Huang, Sanjay Rajendran e Mariusz Malinowski. "Configurations, Power Topologies and Applications of Hybrid Distribution Transformers". Energies 14, n. 5 (24 febbraio 2021): 1215. http://dx.doi.org/10.3390/en14051215.
Testo completoAbstract (sommario):
Distribution systems are under constant stress due to their highly variable operating conditions, which jeopardize distribution transformers and lines, degrading the end-user service. Due to transformer regulation, variable loads can generate voltage profiles out of the acceptable bands recommended by grid codes, affecting the quality of service. At the same time, nonlinear loads, such as diode bridge rectifiers without power factor correction systems, generate nonlinear currents that affect the distribution transformer operation, reducing its lifetime. Variable loads can be commonly found at domiciliary levels due to the random operation of home appliances, but recently also due to electric vehicle charging stations, where the distribution transformer can cyclically vary between no-load, rated and overrated load. Thus, the distribution transformer can not safely operate under highly-dynamic and stressful conditions, requiring the support of alternative systems. Among the existing solutions, hybrid transformers, which are composed of a conventional transformer and a power converter, are an interesting alternative to cope with several power quality problems. This article is a review of the available literature about hybrid distribution transformers.
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Ivanov, Georgi, Anelia Spasova, Valentin Mateev e Iliana Marinova. "Applied Complex Diagnostics and Monitoring of Special Power Transformers". Energies 16, n. 5 (22 febbraio 2023): 2142. http://dx.doi.org/10.3390/en16052142.
Testo completoAbstract (sommario):
As a major component in electric power systems, power transformers are one of the most expensive and important pieces of electrical equipment. The trouble-free operation of power transformers is an important criterion for safety and stability in a power system. Technical diagnostics of electrical equipment are a mandatory part of preventing accidents and ensuring the continuity of the power supply. In this study, a complex diagnostic methodology was proposed and applied for special power transformers’ risk estimation. Twenty special power transformers were scored with the proposed risk estimation methodology. For each transformer, dissolved gas analysis (DGA) tests, transformer oil quality analysis, visual inspections of all current equipment on-site and historical data for the operation of each electrical research were conducted. All data were collected and analyzed under historical records of malfunctioning events. Statistical data for expected fault risk, based on long-term records, with such types of transformers were used to make more precise estimations of the current state of each machine and expected operational resource. The calculated degree of insulation polymerization was made via an ANN-assisted predictive method. Assessment of the collected data was applied to allow detailed information of the state of the power transformer to be rated. A method for risk assessment and reliability estimation was proposed and applied, based on the health index (HI) for each transformer.
40
Dung, Nguyen Thi Ngoc. "Voltage Tap Changer of Power Transformer: Structure, Control and Application". International Journal of Research and Review 10, n. 12 (27 dicembre 2023): 343–51. http://dx.doi.org/10.52403/ijrr.20231237.
Testo completoAbstract (sommario):
This paper focuses on voltage tap changer of transformers to improve voltage quality in electric power systems. The structure and design of this unit will be mentioned with the capability to change the voltage ratio of the transformer in cases of having electric load at high voltage side and not having electric load at medium voltage side. A method to determine standard voltage taps for both high and medium voltage sides of three-winding transformers will be proposed in this paper to provide information for the controller and execute remote control. Moreover, the control structure of whole system, including local and remote-control modes, will be created for the problem of voltage tap changers. An experimental model will be designed to have a virtual calculation, information display and control signal for the problem of voltage tap. Experimental results will prove the ability to calculate standard voltage taps at high and medium voltage taps of a three-winding transformer using values of voltage source and electric loads. Moreover, voltage taps can be also displayed on a human-machine interface software, LCD screen and send control signal after being evaluated by operators. It helps to show scientific meanings of this research and provide an overview about calculating and controlling voltage taps before applying in real control systems. Keywords: On-Load tap changer, Load tap changer, Remote control, Voltage quality, Voltage regulator, Voltage tap, Transformer, Three-winding power transformer.
41
Melnikova, O. S. "Impact of distribution of impurity particles on electric strength of transformer oil". Vestnik IGEU, n. 6 (2019): 41–49. http://dx.doi.org/10.17588/2072-2672.2019.6.041-049.
Testo completoAbstract (sommario):
To extend the service life and ensure the operability of oil-filled transformer equipment, the attention is paid to the development of methods for monitoring the state of oil-barrier insulation. When monitoring the technical condition of transformer oil, the class of liquid purity is determined depending on the rated voltage of the equipment. However, the influence of the parameters of mechanical impurities on the breakdown voltage is not taken into account, thereby lowering the requirements for the quality of oil barrier insulation. This makes it relevant to study the influence of the size distribution of impurity particles on the electric strength of the internal insulation of power transformers and determine the parameters of particles of mechanical impurities to justify the underestimation of the quality indicators of transformer oil in operation. Methods of mathematical statistics were employed using the Gnedenko-Weibull distribution based on the standard values of liquid purity classes. To determine the maximum and minimum voltages, the standard values of the average breakdown voltages and the results of operational tests of transformer oil in a standard spark gap were used. The relation between the particle size of mechanical impurities and the breakdown voltage of transformer oil has been established. The particle size distribution of impurities has been obtained for 12 and 13 classes of liquid purity for power transformers with a voltage of 110–750 kV. The particle size range that defines the maximum and minimum breakdown voltages has been determined, and the values of limit concentrations of mechanical particles have been established. The obtained parameters of impurity particles which determine the maximum and minimum breakdown voltages of the operating oils can be used to evaluate the technical condition when diagnosing the internal insulation of power transformers in order to increase their operational reliability, as well as to adjust the regulatory requirements for the quality of operational transformer oil according to the content of mechanical impurities.
42
Gracheva, E. I., A. N. Gorlov e Z. M. Shakurova. "Calculation of the economy of electric energy in industrial electrical supply systems". Power engineering: research, equipment, technology 22, n. 2 (15 maggio 2020): 65–74. http://dx.doi.org/10.30724/1998-9903-2020-22-2-65-74.
Testo completoAbstract (sommario):
The article examines the main features of the layout of electrical equipment for shop networks of internal power supply with the definition of indicators for a group of shop customers connected to a single power center, affecting the choice of the structure of schemes for shop network sites. The parameters characterizing the circuit topology are revealed. A study is presented of the influence of the load factor of workshop transformers on their reactive power factor, it is proved by calculation by technical and economic criteria the feasibility of replacing a workshop transformer with two with a lower total power. The calculation of energy savings in the in-plant power supply systems. The type of dependences tgφ of transformers ТМ and ТСЗ with various rated powers in the function of loading transformers is established. The most significant factors of the growth of idle power losses during operation are presented. With determination of losses of active and reactive power and electricity in transformers and losses of active power in a high voltage distribution network A feasibility study was carried out on the options for internal power supply schemes with two transformers of lower power installed instead of one, and the feasibility of such a replacement to increase the efficiency of the equipment was proved and the estimated payback period for the investment capital was determined. A comparative analysis of the studied power supply schemes of industrial enterprises with the identification of their advantages and disadvantages.
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Vinogradov, A. V., A. V. Vinogradova, V. E. Bolshev, M. O. Ward, N. V. Makhiyanova e L. V. Dolomaniuk. "Justification for creating a mobile complex to assess electric energy loss in power transformers during the operation process". E3S Web of Conferences 124 (2019): 02009. http://dx.doi.org/10.1051/e3sconf/201912402009.
Testo completoAbstract (sommario):
The paper analyzes the statistical data on the transformers of the Kromsky branch of Oreloblenergo OJSC including the average lifetime of the transformers and no-load losses measured in accordance with the requirements of Russian standard GOST 3484.1. The analysis indicates that the declared passport data differ from the measured data. There is also the analysis of technical solutions to improve the power transformer design including to development of new types of electrical steel used in transformer cores, superconducting materials for winding. The article gives an understanding of the advantages and disadvantages of using these technologies as well as the possible reduction of electrical losses. In conclusion there is the justification for creating the mobile measuring complex to assess electric energy loss in power transformers during operation without disconnecting the load. The paper describes the result achieved using such a mobile measuring complex along with the economic effect of creating the project.
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Olosunde, Akinlolu, e Rowland Benjamin Ekpo. "HALF EXPONENTIAL POWER MODEL FOR THE FIRST TIME FAILURE OF POWER DISTRIBUTION TRANSFORMERS IN NIGERIA". Indonesian Journal of Statistics and Its Applications 4, n. 2 (31 luglio 2020): 321–26. http://dx.doi.org/10.29244/ijsa.v4i2.640.
Testo completoAbstract (sommario):
Transformer failure is a major problem confronting the Nigerian power sector, hindering the transmission and distribution of electric power to various households, institutions, and industries. Many of these transformer developed problem due to the old age of the transformers, overloading, in-availability of technical expertise, poor maintenance culture, manufacturer's faults, just to mention few. The present research focuses on providing half exponential power model for the failure of already installed transformers, with respect to years of installation up to the time of the first failure, using secondary data from the south western part of Nigeria as a case study. The results obtained showed that half exponential power performed better in modeling the first time failure of power transformers. This was possible because of the present of shape parameter which gives flexibility to half exponential power when compared with a half normal distribution.
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Lee, Choongman, Gyu-Jung Cho e Joorak Kim. "Development of Scott Transformer Model in Electromagnetic Transients Programs for Real-Time Simulations". Applied Sciences 11, n. 12 (21 giugno 2021): 5752. http://dx.doi.org/10.3390/app11125752.
Testo completoAbstract (sommario):
This paper presents a Scott transformer model to be applied in electromagnetic transients (EMT) programs, particularly in the absence of a detailed Scott transformer model for performing real-time simulations (RTS). Regarding a Scott transformer, a common topology for converting a three-phase network into two single-phase networks, the transformer model in EMT programs is essential to simulate large-scale electric railway systems. A code-based model has been developed to simulate the transformer in RTS directly and contain the transformer’s actual impedance characteristics. By establishing a mathematical foundation with the current injection method, we presented a matrix representation in conjunction with a network solution of EMT programs. The proposed model can handle more practical parameters of Scott transformers with a relatively low computational load. Thus, it supports the flexible computation of real-time simulators with a finite number of processor units. The accuracy of the model is verified by simulating it and comparing the simulation results with an industrial transformer’s certified performance. Furthermore, a case study involving a comparison of the results with the field measurement data of an actual Korean railway system demonstrated the efficacy of the model.
46
Hendri, Hendri, Yanuar Zulardiansyah Arief e Abdul Syukur. "Testing of Palm Oil-Based Electric Power Transformer Insulation Oil as a Renewable Energy Source". Jurnal Pendidikan Teknologi Kejuruan 6, n. 1 (28 febbraio 2023): 56–63. http://dx.doi.org/10.24036/jptk.v6i1.32323.
Testo completoAbstract (sommario):
Reducing petroleum resources and environmental problems, alternative insulating oils with biodegradable characteristics have become an alternative. Esterification of palm-based oil is expected to provide better and optimum electrical properties. The esterification of palm oil will be carried out as a test sample and observed for its electrical, physical and chemical properties such as PD characteristics, breakdown voltage, dissipation factor, viscosity, flash point, etc. The effect of thermal aging on oil samples will also be carried out to simulate real situations in power transformer applications. Then after obtaining the best formulation from the sample it will be used as insulating oil in electric power transformers (100kVA). The purpose of this research is to apply esterified palm oil as an electric power transformer oil. The method used in this research includes field research. Field research includes taking oil samples, measuring the breakdown voltage of transformer oil, and the color of transformer oil. The results obtained are insulating oil for electric power transformers based on palm oil. Palm oil has the advantage of being an environmentally friendly, biodegradable and renewable oil compared to the transformer oil used today which is based on petroleum. With the realization of transformer oil based on palm oil, it is hoped that it can provide great economic opportunities for Indonesia as one of the largest palm oil producers in the world and can also provide added value and increase the competitiveness of the palm oil industry in the future.
47
Bustamante, Sergio, Mario Manana, Alberto Arroyo, Pablo Castro, Alberto Laso e Raquel Martinez. "Dissolved Gas Analysis Equipment for Online Monitoring of Transformer Oil: A Review". Sensors 19, n. 19 (20 settembre 2019): 4057. http://dx.doi.org/10.3390/s19194057.
Testo completoAbstract (sommario):
Power transformers are the most important assets of electric power substations. The reliability in the operation of electric power transmission and distribution is due to the correct operation and maintenance of power transformers. The parameters that are most used to assess the health status of power transformers are dissolved gas analysis (DGA), oil quality analysis (OQA) and content of furfuraldehydes (FFA) in oil. The parameter that currently allows for simple online monitoring in an energized transformer is the DGA. Although most of the DGA continues to be done in the laboratory, the trend is online DGA monitoring, since it allows for detection or diagnosis of the faults throughout the life of the power transformers. This study presents a review of the main DGA monitors, single- or multi-gas, their most important specifications, accuracy, repeatability and measurement range, the types of installation, valve or closed loop, and number of analogue inputs and outputs. This review shows the differences between the main existing DGA monitors and aims to help in the selection of the most suitable DGA monitoring approach according to the needs of each case.
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Gotovkina, Elena, Vladimir Tyutikov, Nikolay Smirnov, Vladimir Lebedev e Evgeniy Bushuev. "Influence of insolation and ambient temperature on operation of digital voltage transformers in Russia". MATEC Web of Conferences 178 (2018): 09005. http://dx.doi.org/10.1051/matecconf/201817809005.
Testo completoAbstract (sommario):
The present study is devoted to questions connected with influence of solar radiation and high values of ambient air temperatures on work of digital voltage transformers. The developed designs of digital voltage transformers are included in smart grid system of technical and commercial metering of electric energy consumption. The analysis of the unfavorable conditions for work of digital voltage transformers for the conditions of Russia in summer is carried out. The results of mathematical simulation for thermal state of transformers, obtained with the help of COMSOL Multiphysics program based on the finite element method, are presented. Experimental research regarding the thermal field of resistive voltage divider transformer was conducted on a verified mathematical model in order to determine the position of resistive elements where their self-heating is minimal.
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Rigot, Valentin, Tanguy Phulpin, Jihen Sakly e Daniel Sadarnac. "A New 7 kW Air-Core Transformer at 1.5 MHz for Embedded Isolated DC/DC Application". Energies 15, n. 14 (19 luglio 2022): 5211. http://dx.doi.org/10.3390/en15145211.
Testo completoAbstract (sommario):
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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Gapon, Dmytro, Oleg Gryb, Igor Karpaliuk, Andrey Zuev e Tetiana Donetska. "Electric power metering with its low quality". Bulletin of the National Technical University "KhPI". Series: Energy: Reliability and Energy Efficiency, n. 2 (3) (30 dicembre 2021): 49–53. http://dx.doi.org/10.20998/2224-0349.2021.02.12.
Testo completoAbstract (sommario):
The issue of electricity metering with low quality is being considered. Special attention is paid to checking the connection metering scheme with low quality of electrical energy. It is shown that a specific circuit design can affect the accuracy of metering of electrical energy in case of poor quality of electrical energy. In distribution networks intended for power supply of industrial enterprises, reactive power is also active. If the consumer has compensating devices, the directions of active and reactive power can be opposite. It is noted that current transformers, selected taking into account the short-circuit current or the characteristics of relay protection, do not provide metering accuracy due to the increased transformation ratio, forcing the installation of an additional set of current transformers or transferring the meters to another point in the network. Thus, the current transformation ratio of the current transformer is somewhat different from the nominal one, and the secondary current vector forms a certain angle with the primary current vector. The voltage error is manifested in a slight decrease in the secondary voltage under load. The angular error is characterized by a certain angle between the vectors of the primary and secondary stress. The value of the errors depends on the load power of the transformer. The maximum allowable voltage drop of the transformer determines the accuracy class. A rated power is set for each accuracy class. Thus, the voltage transformer, depending on the load, can operate in different accuracy classes. Changing the accuracy classes leads to errors in the measurements of metering devices and requires appropriate correction. The article reveals the reasons for the occurrence of such errors, which makes it possible to develop methods and, as a consequence, create devices to prevent the described errors of metering devices.