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Journal articles on the topic 'Power transformer inrush current'
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1
Nitin Mahadeo Khandare. "Differentiation Between Inrush and Fault Currents in Transformers to Avoid Malfunctioning of Protection Scheme." Journal of Information Systems Engineering and Management 10, no. 38s (2025): 421–29. https://doi.org/10.52783/jisem.v10i38s.6865.
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The power transformers are key components of the today's power systems. To ensure smooth operation, it modifies the supply's voltages and current levels at different power system stages. Differentiating between fault currents and inrush currents is the most crucial component of transformer protection. The most vital part of a protection strategy for transformer is the ability to differentiate between inrush current and internal fault currents. Therefore, safeguarding it is crucial to ensuring the power system operates steadily and consistently. Inrush current is the primary cause of protective system breakdowns. Thus, timely and precise fault current and inrush current discrimination is essential for reliable and satisfying power system operation.
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Patil, Bhushan Prataprao, and Shah Paresh Jaychand Dr. "A REVIEW ON FAULT CLASSIFICATION METHODOLOGIES IN TRANSFORMER"." International Journal of Research and Analytical Reviews 6, no. 1 (2019): 449–57. https://doi.org/10.5281/zenodo.8434792.
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This paper presents a survey on different fault classification methodologies in transformer, when the transformer becomes operational, it experiences a magnetizing inrush current with a magnitude that can range from six to eight times the rated current. This can cause the differential relay to trigger incorrectly and cutting off the transformer's supply lines without need. To avoid deceptively tripping the differential relay and make sure the transformer is operating properly, it's critical to differentiate between inrush current and internal fault current. The second harmonic restraint relay is used by traditional protection systems to distinguish between the internal fault current and the inrush current. The scale and complexity of power systems are growing along with the energy demand, making rapid, stable, and dependable protection systems necessary to preserve crucial components like transformers. Thus, current research focuses on creating unique algorithms for precise separation between internal fault current and inrush current. This review study, which is meant to help researchers new to this topic, examines numerous methods used to distinguish between internal fault current and inrush current in transformers.
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Wang, Xiao Fang. "Transformer Inrush Current Identification Based on EMD+TEO Methods." Applied Mechanics and Materials 556-562 (May 2014): 3129–33. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.3129.
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Transformers is one of the most important power system components, its role is to carry power conversion and transmission, transformer manufacturing technology continues to develop, but there is a surge of its problems, factors that have caused the transformer inrush load switching, transformers string parallel operation and fault lines, etc, as a transformer inrush phenomenon often can lead to malfunction of its protection, the correct identification is particularly important means of this paper, the combination of EMD and TEO transformer inrush and fault operation effective identification, theory and simulation confirms the validity and reliability of the algorithm.
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Xiang, Dong, and Fei Yu. "Characteristic Analysis of Ship Transformer Magnetizing Inrush Current and its Suppression Method." Advanced Materials Research 1070-1072 (December 2014): 1154–58. http://dx.doi.org/10.4028/www.scientific.net/amr.1070-1072.1154.
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Medium voltage in the electric power system of ship typically is powered by a large capacity transformer for low voltage electrical apparatus. When switching on, the primary side of transformer will produce very large current, which would endanger the safe operation of power for ships. The mechanism and characteristics of magnetizing inrush current is analyzed when the transformer switches with no load. We think that the reason caused magnetizing inrush current is transformers saturation. Pre-excitation is presented through a small volume transformer magnetizing method of suppressing the inrush current of transformer and validated by simulation and experiment.
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Nadhirah, Nurul Fatin, Hana Abdull Halim, Nurhakimah Mohd Mukhtar, and Samila Mat Zali. "Varying the energisation condition to mitigate sympathetic inrush current." International Journal of Electrical and Computer Engineering (IJECE) 13, no. 6 (2023): 5975. http://dx.doi.org/10.11591/ijece.v13i6.pp5975-5985.
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Transformers are generally easy to access and can contribute significantly to entire power system. When a transformer is turned on for the first time, it produces a magnetising inrush current which acts as a starting current. Energisation of transformer has a substantial impact on inrush current and transformer that are connected in parallel. Sympathetic inrush current is a phenomenon that appears when a transformer is switched-on in network whereas the other transformers that was earlier energised. Besides, when sympathetic inrush phenomena occur, the peak and period fluctuate significantly. In this paper, the transformers will be energised in three different ways and each condition will be explored in depth. The operation time of the transformer’s energisation whether it is energised simultaneously or at different times are tested and analysed in terms of their characteristics. It is performed using power system computer aided design (PSCAD) software, starting with a develop model of the energisation and then generate the outcomes. The results of the simulation demonstrate that energising the transformer in different ways can give different effect on the sympathetic inrush current, as well as the variables that affect it and methods for reducing it.
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Desai, B. T., H. O. Gupta, and M. K. Vasantha. "Current transformer performance for inrush current in power transformers." Electric Power Systems Research 14, no. 3 (1988): 237–41. http://dx.doi.org/10.1016/0378-7796(88)90057-0.
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SACHIN, S. DADHE, DR.N.M.LOKHANDE, and A. C. GIDDE PROF. "CALCULATION OF MAGNETIZING INRUSH CURRENT IN TRANSFORMER." JournalNX - A Multidisciplinary Peer Reviewed Journal NCMTEE-2K17 (March 26, 2017): 108–11. https://doi.org/10.5281/zenodo.1452050.
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When transformer is energized its current reaches very high value generally approximately 10 to 20 times greater than its rated current. This paper deals with study of calculation of inrush current in transformer. Different methods are available to calculate inrush current in transformer. Different methods to calculate inrush current in transformer which depends on operating conditions and type of transformer; which are explained in this paper.The calculation of inrush current is necessary is necessary to predefine the protective system adapted to power transformer. https://journalnx.com/journal-article/20150270
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Kuvshinov, A., V. Vakhnina, D. Kretov, and A. Chernenko. "The Assessment of a Magnetizing-Current Inrush of a Power Transformer." Journal of Physics: Conference Series 2096, no. 1 (2021): 012135. http://dx.doi.org/10.1088/1742-6596/2096/1/012135.
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Abstract The study aims to propose an analytical tool for determining the parameters of the power transformer magnetizing inrush current caused by geomagnetically induced currents flowing through high-voltage windings with a grounded neutral under the impact of geomagnetic disturbances on the power grid. The analytical equations for the instantaneous magnetizing current under geomagnetic disturbances were obtain by mathematical model of magnetizing branch for a shell-type power transformer. A model base on a magnetization characteristics piecewise-linear approximation for the electrical steel. The magnetizing inrush current amplitude and duration it was found depends on the intensity of geomagnetic disturbances and in cope-link with the dynamics of the power transformer core saturation transient process were determined the changes in the magnetizing inrush current amplitude and duration under geomagnetic disturbances. The magnetizing inrush current amplitude it was found may reach the level of short-circuit current periodic component at the point of power transformer grid connection. The results were verify by comparing the design and experimental values of the magnetizing inrush current amplitude. The advantages of proposed mathematical model shown with justifying the analogy between core saturation under connecting of power transformer to a grid and under geomagnetically induced currents exposed. The piecewise-linear approximation of power transformer magnetization characteristic, allow to obtain the amplitude value of magnetizing inrush current caused by geomagnetically induced currents with an accuracy of 6% and can be used with power grid steady state and transient simulation under geomagnetic disturbances.
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Nassim, A. Iqteit, and Yahya Khalid. "Simulink model of transformer differential protection using phase angle difference based algorithm." International Journal of Power Electronics and Drive System (IJPEDS) 11, no. 2 (2020): 1088–98. https://doi.org/10.11591/ijpeds.v11.i2.pp1088-1098.
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An application of phase-angle-difference based algorithm with percentage differential relays is presented in this paper. In the situation where the transformer differential relay is under magnetizing inrush current, the algorithm will be utilized to block the process. In this study, the technique is modeled and implemented using Simulink integrated with MATLAB. The real circuit model of power transformer and current transformers are considered in the simulation model. The results confirmed the effectiveness of the technique in different operation modes; such as, magnetizing inrush currents, current transformers saturation and internal transformer faults.
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Banerjee, Mudita, and Anita Khosla. "Mitigation of magnetising inrush current in three–phase power transformer." Indonesian Journal of Electrical Engineering and Computer Science 20, no. 1 (2020): 39. http://dx.doi.org/10.11591/ijeecs.v20.i1.pp39-45.
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<span>During energization of no – load transformers, a high and peaky current flow on the primary side which has rich second harmonics. This current is magnetising inrush current and it is generated when transformer core is driven deep into saturation. This current has various disturbances on transformer attribute; reduced life-span, major voltage drop, insulation weakening, electrical and mechanical vibrations in coils, difficulties in protecting relays and all leads to poor power quality of the electric system. This paper presents the analysis and comparison of recent techniques to reduce the magnitude of inrush current during energization of power transformer. The simulation results are provided for Pre – insertion of resistors, Controlled swithing and Pre – fluxing method. The best method is suggested for mitigating inrush current by simulating in MATLAB/SIMULINK environment.</span>
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Mudita, Banerjee, and Khosla Anita. "Mitigation of magnetising inrush current in three-phase power transformer." Indonesian Journal of Electrical Engineering and Computer Science 20, no. 1 (2020): 39–45. https://doi.org/10.11591/ijeecs.v20.i1.pp39-45.
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During energization of no-load transformers, a high and peaky current flow on the primary side which has rich second harmonics. This current is magnetising inrush current and it is generated when transformer core is driven deep into saturation. This current has various disturbances on transformer attribute; reduced life-span, major voltage drop, insulation weakening, electrical and mechanical vibrations in coils, difficulties in protecting relays and all leads to poor power quality of the electric system. This paper presents the analysis and comparison of recent techniques to reduce the magnitude of inrush current during energization of power transformer. The simulation results are provided for Pre-insertion of resistors, Controlled swithing and Pre-fluxing method. The best method is suggested for mitigating inrush current by simulating in MATLAB/SIMULINK environment.
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Nurul Fatin Nadhirah Subli, Hana Abdull Halim, and Haziah Abd Hamid. "Assessment and Mitigation Studies of Voltage Sags during Sympathetic Inrush Current." Journal of Advanced Research in Applied Sciences and Engineering Technology 46, no. 2 (2024): 50–63. http://dx.doi.org/10.37934/araset.46.2.5063.
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The system voltage may be negatively impacted by the transformer’s energisation which draws a large value of magnetising inrush current for a few seconds. During the transformer’s energisation process, it experiences an unexpected saturation. When the transformer is saturated, the growth of magnetising inrush current, sympathetic inrush current and voltage sags are a few issues that are appear. Numerous variables that affect the inrush current and the resulting voltage sags were taken into consideration. This is due to the fact that the energisation of a large power transformer may result in a high voltage sag which relies on a value of parameters, including the duration of the circuit breaker closing time. One of the most essential objectives for power quality is the research of voltage sags that appear in a network. The goal of this project is to investigate sympathetic and inrush currents as well as to assess the voltage sag that occurs during transformer energisation and how severe it is. In this paper, the voltage sags are analysed by modelling 100kVA, 11kV/415V of wye-delta of single line (circles) transformer and using PSCAD software. It is expected to observe the magnitude, the duration and the percentage of voltage sags in order to make a comparison result between single connected transformer, two parallel-connected transformers and three parallel-connected transformers. To predict the severity of the sympathetic inrush current, the effects of voltage sags and their assessment is developed. As a result, it has been shown that the more energisation of the transformers, the peak of inrush current increases causing the higher magnitude and the longer duration of voltage sags. In conclusion, the voltage sags also become severe and persists for a longer duration when the number of transformers in operation are increased.
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Šulc, Ivan, Robert Sitar, and Antun Mikulecky. "An aspect of transformer inrush current." Journal of Energy - Energija 63, no. 1-4 (2022): 150–55. http://dx.doi.org/10.37798/2014631-4173.
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Paper analyzes a sparking phenomena that were observed on power transformers during their first few energizing. Sparks occurred on the flange between tank cover and tank side, in spite of the fact that a jumper (copper link) was used. The phenomenon was observed on transformers from different manufacturers, with various transformer ratings, three or five limb core. Paper proposes a simple electromagnetic model for analyzing the phenomena. Three-phase power transformer is modeled in finite element method (FEM) magnetic software. Simplified 3D transformer model is used in order to simulate well known core saturation during the inrush current event. Voltages between tank cover and tank side are calculated for simulated conditions. The same model is used for calculation of possible currents flowing between tank cover and tank side, showing that a value of several kA can be reached. In spite of the fact that the observed phenomenon is harmless mitigation measures are proposed. However, by doing nothing, sparking would disappear very soon.
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Iqteit, Nassim A., and Khalid Yahya. "Simulink model of transformer differential protection using phase angle difference based algorithm." International Journal of Power Electronics and Drive Systems (IJPEDS) 11, no. 2 (2020): 1088. http://dx.doi.org/10.11591/ijpeds.v11.i2.pp1088-1098.
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<p class="p1">An application of phase-angle-difference based algorithm with percentage differential relays is presented in this paper. In the situation where the transformer differential relay is under magnetizing inrush current, the algorithm will be utilized to block the process. In this study, the technique is modeled and implemented using Simulink integrated with MATLAB. The real circuit model of power transformer and current transformers are considered in the simulation model. The results confirmed the effectiveness of the technique in different operation modes; such as, magnetizing inrush currents, current transformers saturation and internal transformer faults.</p>
15
Ge, Wenqi, Chenchen Zhang, Yi Xie, Ming Yu, and Youhua Wang. "Analysis of the Electromechanical Characteristics of Power Transformer under Different Residual Fluxes." Energies 14, no. 24 (2021): 8244. http://dx.doi.org/10.3390/en14248244.
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When the electromagnetic transients occur in a power transformer, an inrush current is generated in its winding. The inrush current not only affects the performance of the transformer windings, but also affects the lifetime of the transformer. Many factors affect the inrush current, the most influential ones among which are the closing phase angle and the residual flux. In this paper, a dry-type transformer simulation model is built to analyze the influence of the inrush current on the performance of transformer windings during no-load reclosing conditions. Firstly, the inrush current was generated in the transformer windings during the no-load reclosing operation under different residual fluxes. Secondly, the field-circuit coupling 3d finite element method is used to analyze the electromagnetic force at different locations of the transformer windings under the influence of different inrush currents. The results of winding structural parameter variations are obtained through electromagnetic-structural coupling simulation, and the electromagnetic forces are used as the input parameter for the structural analysis. Finally, the residual flux is generated by controlling the opening and closing angle of the transformer through the phase-controlled switch, and the winding electromechanical characteristics are tested under different residual fluxes. Finally, comparisons of the test and simulation results are drawn to verify the impact of the closing angle and residual flux on inrush current and the winding deformation during the no-load reclosing conditions.
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Ali Naghizadeh, Ramezan, Behrooz Vahidi, and Seyed Hossein Hosseinian. "Calculation of inrush current using adopted parameters of the hysteresis loop." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 33, no. 5 (2014): 1794–808. http://dx.doi.org/10.1108/compel-08-2012-0133.
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Purpose – The purpose of this paper is to propose an accurate model for simulation of inrush current in power transformers with taking into account the magnetic core structure and hysteresis phenomenon. Determination of the required model parameters and generalization of the obtained parameters to be used in different conditions with acceptable accuracy is the secondary purpose of this work. Design/methodology/approach – The duality transformation is used to construct the transformer model based on its topology. The inverse Jiles-Atherton hysteresis model is used to represent the magnetic core behavior. Measured inrush waveforms of a laboratory test power transformer are used to calculate a fitness function which is defined by comparing the measured and simulated currents. This fitness function is minimized by particle swarm optimization algorithm which calculates the optimal model parameters. Findings – An analytical and simple approach is proposed to generalize the obtained parameters from one inrush current measurement for simulation of this phenomenon in different situations. The measurement results verify the accuracy of the proposed method. The developed model with the determined parameters can be used for accurate simulation of inrush current transient in power transformers. Originality/value – A general and flexible topology-based model is developed in PSCAD/EMTDC software to represent the transformer behavior in inrush situation. The hysteresis model parameters which are obtained from one inrush current waveform are generalized using the structure parameters, switching angle, and residual flux for accurate simulation of this phenomenon in different conditions.
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YAHIOU, Abdelghani, Amar MAAFA, Hacene MELLAH, et al. "Point on Wave Energization Strategy and Sequential Phase Shifting for Sympathetic Inrush Current Mitigation in Three-Phase Transformer - Measurement." Eurasia Proceedings of Science Technology Engineering and Mathematics 26 (December 30, 2023): 578–88. http://dx.doi.org/10.55549/epstem.1411094.
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Inrush currents generated when an electrical transformer is energized can achieve great values and cause abnormal difficulties in the power grid. The sympathetic inrush current phenomenon is resulted in the power system when a transformer is energized with the existence of other transformer already energized. The main objective of this article is the attenuation of sympathetic inrush current in a three-phase transformer. The control technique is carried out by the consideration of the residual flux value when de-energizing the transformer as well as respecting the three-phase shifting. Moreover, an experimental setup to measure the inrush current will be presented. Furthermore, a technique for controlling the circuit breaker to energize a 2 kVA three-phase transformer which allows the sympathetic inrush current to be attenuated was also applied and tested in the experimental. The contribution of this paper is that this technique is applied in measurements with an in-depth estimation of the residual flux. The proposed technique made it possible to completely eliminate the sympathetic inrush current.
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Key, Sopheap, Gyu-Won Son, and Soon-Ryul Nam. "Deep Learning-Based Algorithm for Internal Fault Detection of Power Transformers during Inrush Current at Distribution Substations." Energies 17, no. 4 (2024): 963. http://dx.doi.org/10.3390/en17040963.
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The reliability and stability of differential protection in power transformers could be threatened by several types of inferences, including magnetizing inrush currents, current transformer saturation, and overexcitation from external faults. The robustness of deep learning applications employed for power system protection in recent years has offered solutions to deal with several disturbances. This paper presents a method for detecting internal faults in power transformers occurring simultaneously with inrush currents. It involves utilizing a data window (DW) and stacked denoising autoencoders. Unlike the conventional method, the proposed scheme requires no thresholds to discriminate internal faults and inrush currents. The performance of the algorithm was verified using fault data from a typical Korean 154 kV distribution substation. Inrush current variation and internal faults were simulated and generated in PSCAD/EMTDC, considering various parameters that affect an inrush current. The results indicate that the proposed scheme can detect the appearance of internal faults occurring simultaneously with an inrush current. Moreover, it shows promising results compared to the prevailing methods, ensuring the superiority of the proposed method. From sample N–3, the proposed DNN demonstrates accurate discrimination between internal faults and inrush currents, achieving accuracy, sensitivity, and precision values of 100%.
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Banerjee, Mudita, and Dr Anita Khosla. "Comparison and Analysis of Magnetizing Inrush and Fault Condition for Power Transformer." International Journal of Engineering & Technology 7, no. 4.5 (2018): 126. http://dx.doi.org/10.14419/ijet.v7i4.5.20027.
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This paper presents the second harmonics present in the primary current of a power transformer at different conditions using Fast Fourier Transform and Total Harmonic Distortion techniques to analyze the inrush condition and to distinguish it with fault condition of a power transformer. Result shows that the 2nd harmonic content is pre-dominant in inrush condition of primary current of the power transformer. It is observed that there are significant differences amongst the parameters found during inrush condition, normal condition and internal fault condition which are useful in the identification of magnetizing inrush current of power transformer. The simulation is done in MATLAB/SIMULINK.
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Huang, Qiyue, and Lizhu Jia. "Research on magnetizing inrush current of microgrid based on Grey identification." Journal of Physics: Conference Series 2237, no. 1 (2022): 012005. http://dx.doi.org/10.1088/1742-6596/2237/1/012005.
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Abstract With the large-scale access of wind and light energy, the power system is gradually developing towards the micro grid with low inertia. AC microgrid often uses multiple parallel transformers to supply power to the load at the same time. In case of power failure due to a fault or maintenance, the parallel transformer needs to be powered on and closed without load to restore power supply. The parallel transformer is easier to saturate, the core remanence is higher, and the peak value of inrush current is larger, which has an impact on the stability of microgrid. It will also lead to misoperation of transformer differential protection and affect the safe and stable operation of power system. Therefore, a switching method of parallel transformer based on Grey recognition is proposed. Firstly, the generation mechanism of inrush current is analyzed theoretically, and then the waveform shape characteristics are analyzed. The grey whitening weight clustering method is used to identify the feature set to complete the magnetizing inrush current locking and ensure that the protection does not misoperate. Finally, the PSCAD simulation model is established to simulate the AC microgrid to verify the feasibility of this method.
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Manusov, Vadim, Dmitry Ivanov, and Elena Ivanova. "Modeling and Experimental Study of the Inrush Current of a High-Temperature Superconducting Transformer." Problems of the Regional Energetics, no. 2(62) (April 2024): 46–56. http://dx.doi.org/10.52254/1857-0070.2024.2-62.05.
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Inrush current in high-temperature superconducting (HTS) transformers is a little-studied phenomenon. After connecting to the power grid, a current flow through the windings which exceeding the critical current value of the superconducting tape. It may cause significant overheating and thermal damage of winding. The purpose of the study is to develop a mathematical model for calculating inrush current pulses in a HTS transformer and its verification by physical experiments. To achieve the goal of the study, a mathematical model has been developed that accurately represents the electromagnetic and thermal transient processes after HTS transformer is turned on at idling or under load. The model considers the critical parameters of the HTS tapes, the process of heating and cooling of the windings, quench characteristics, and the electrical and magnetic parameters of the transformer. Good compliance of the experimental results and mathematical modeling with a deviation of 1.99 % allowed us to verify the model. The most important result is the creation of a mathematical model of the HTS transformer at the moment of connecting to power grid. This model represents the temperature changing of the windings during the loss of superconductivity. The developed model can be used in the analysis and modeling of inrush current in designed and operating HTS transformers for any power. The obtained results are significant for determine the optimal starting characteristics, geometric and electrical parameters of HTS transformers. The proposed methods for reducing the inrush current ensure safe and reliable operation of the HTS transformer when switched on at idling or under load.
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KUVSHINOV, Aleksey A., Vera V. VAKHNINA, and Aleksey N. CHERNENKO. "Evaluation of the Power Transformer Magnetizing Inrush Currents." Elektrichestvo 10, no. 10 (2020): 20–32. http://dx.doi.org/10.24160/0013-5380-2020-10-20-32.
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The mathematical model of a shell-core power transformer’s magnetization branch is substantiated. By using the model, analytical expressions for the magnetizing current instantaneous values under the conditions of geomagnetic disturbances can be obtained. Quantitative assessments of the magnetizing inrush current amplitudes and durations versus the geomagnetic disturbance intensity are obtained. The dynamics of the power transformer magnetic system saturation transient and changes in the magnetization inrush current amplitudes and durations after a sudden occurrence of geomagnetic disturbances are shown. The error of estimating the magnetizing inrush current amplitudes under geomagnetic disturbances is determined based on comparison with experimental data.
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Petrescu, L., E. Cazacu, V. Ioniţă, and Maria-Cătălina Petrescu. "An Experimental Device for Measuring the Single-Phase Transformers Inrush Current." Scientific Bulletin of Electrical Engineering Faculty 19, no. 1 (2019): 18–22. http://dx.doi.org/10.1515/sbeef-2019-0004.
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AbstractElectrical transformers are essential parts of power supply networks and it is important that their life-time to be preserved. The inrush current of this devices could determine malfunctioning of the transformers or even others component of the network. For this reason, determining the inrush current for single-phase transformers is an important issue in power quality analysis of electrical grids. In this paper we presented an experimental device (hardware set-up and software program) that can measure this in rush current features for small transformers (up to 10 kVA). Also, the device affords the users to measure inrush current knowing the geometry of the transformer, the dimensions and the magnetic characteristic of the core.
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Azeem, Abdul, Majid Jamil, Shamimul Qamar, Hasmat Malik, and Rayees Ahmad Thokar. "Design of Hardware Setup Based on IEC 61850 Communication Protocol for Detection & Blocking of Harmonics in Power Transformer." Energies 14, no. 24 (2021): 8284. http://dx.doi.org/10.3390/en14248284.
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In this paper, the authors have developed a hardware model for blocking even and odd harmonics of a power transformer. In the proposed hardware model, intelligent differential & over-current relays are used for the blocking of harmonics of a power transformer. The harmonic restraint function on the differential relay (7UT61) prevents the relay from tripping during transformer magnetizing inrush current. However, the over-current relays which are used for back up protection does not have a harmonic restraint element, and over-current relay trips due to magnetizing inrush current, causes unwanted interruptions and power failures. The establishment of harmonic blocking scheme for over-current protection in power transformers is an important finding of this research study. IEC61850 standard-Based GOOSE (Generic Object Oriented Substation Event) applications used in power transformer protection for fast detecting and clearing of faults is an interested study presented in the proposed work.
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Tseng, H. T., and J. F. Chen. "Voltage compensation-type inrush current limiter for reducing power transformer inrush current." IET Electric Power Applications 6, no. 2 (2012): 101. http://dx.doi.org/10.1049/iet-epa.2011.0151.
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Nițu, Maria-Cristina, Ileana-Diana Nicolae, Livia-Andreea Dina, and Paul-Mihai Mircea. "Power Transformer Inrush Current Analysis: Simulation, Measurement and Effects." Applied Sciences 14, no. 23 (2024): 10926. http://dx.doi.org/10.3390/app142310926.
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Inrush current is still a persistent problem affecting the quality of the power system. This paper presents the theoretical aspects of this transient phenomenon, the simulation of the phenomenon for prediction purposes and its measurement in a test laboratory. In the operation of power transformers, there may also be cases where electrical phenomena affecting the operation of transformers may overlap. When power transformers are in operation, there may also be cases where electrical phenomena affecting their operation overlap. This paper includes a study describing such a situation, where the maximum value of the inrush current is amplified by the fact that the series resonance condition has been met. The intersection of these electrical phenomena resulted in internal and external electrical discharges that led to the overhaul of a 440 MVA transformer; the description of this situation is based on field data. The paper focuses on real information and situations that support the development of a maintenance management schedule based on accurate and up-to-date data. The information presented in this paper will be particularly useful to personnel specializing in power transformer design and/or those monitoring/operating high power transformers in the energy sector, but can also be a teaching aid for students interested in such transient phenomena.
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Seo, Hun-Chul, and Gi-Hyeon Gwon. "Systematization of the Simulation Process of Transformer Inrush Current Using EMTP." Applied Sciences 9, no. 12 (2019): 2398. http://dx.doi.org/10.3390/app9122398.
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An inrush current is generated when a transformer is energized. This current has a large magnitude and rich harmonics, thereby causing mal-operation of the protection relay. Therefore, the development of countermeasures against inrush current is necessary, and this study has been performed by computer simulations. However, it is difficult for a power system operator to perform a computer simulation as it is difficult to determine what data should be selected and entered. Therefore, this paper establishes the simulation process of transformer inrush current using the Electromagnetic Transients Program (EMTP). Two methods to simulate the transformer inrush current are described in detail. Based on the actual 154 kV transformer test report in Korea, the simulation results of the inrush current using the two methods are discussed.
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CISNEROS VILLALOBOS, LUIS, JOSÉ GERARDO VERA DIMAS, DAVID MARTÍNEZ MARTÍNEZ, JOSE FRANCISCO SOLIS VILLAREAL, and OSCAR ESPINOZA ORTEGA. "SYMPATHETIC INRUSH CURRENT PHENOMENA IN PARALLEL CONNECTED TRANSFORMERS CONSIDERING GRADING CAPACITANCE." DYNA 100, no. 3 (2025): 211–18. https://doi.org/10.52152/d11354.
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The article presents the results of a research study focused on the phenomenon of sympathetic inrush current caused by the sequential energization of two transformers connected in parallel with another transformer already in operation, introducing the novelty of considering the effect of the circuit breaker's grading capacitance. The aim is to propose an operational practice that reduces the intensity of this phenomenon and minimizes the risk of blackouts or equipment failures during the energization or re-energization of the transformers.The studied system is common in the central Mexican electrical grid and consists of a substation with three 100 MVA transformers. Through these transformers, it is possible to transfer energy between the 230 kV and 85 kV networks. The research employs electrical system modeling using the ATP (Alternative Transients Program) software to simulate common practical cases involving the manipulation of substation circuit breakers during the operation of the power grid. The program allows for controlling the closing time of the circuit breakers to create critical scenarios during the energization process. It also uses a transformer model with saturation characteristics provided by the manufacturer, including a certain level of remanent magnetization. The results show that the magnitudes, waveforms, and durations of both the magnetizing inrush current and the sympathetic inrush current can cause imbalances and affect the normal operation of the electrical system. This may lead to transformer outages due to the incorrect functioning of differential and overcurrent relays or problems with the quality of power within the system. However, the results also suggest that the proper handling of certain circuit breakers can have beneficial effects, reducing the intensity of the phenomenon and improving the quality and reliability of the power supply. Keywords: Sympathetic inrush current, three transformers in parallel, ATP simulation, power systems operation, grading capacitor.
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Alkhayyat, Mahmood T., Faisal Aiwa, Ali Salah Alhfidh, and Mohammed Y. Suliman. "Power Transformer Inrush Current Minimization During Energization using ANFIS based Peak Voltage Tracking Approach." International Journal of Electrical and Electronics Research 12, no. 1 (2024): 211–18. http://dx.doi.org/10.37391/ijeer.120130.
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Energizing the power transformer at no load causes inrush current flow. The value of this current depends on main three factors, the residual and saturation flux of the transformer core, the rating of the transformer, and the switching instant. Inrush current may decrease the life of the transformer and causes mall function of the protective relays. Many efforts were done for limiting the inrush current using a current limiter or improve the core material to reduce residual flux. Other treating is to control energizing instance. This paper focused on controlling the instant of the transformer energization switch using fuzzy logic inference system. A new technique depends on adaptive seeking the crest of the voltage waveform. By this method there is no need to zero-crossing technique or phase looked loop. At this point, the flux of the core reaches the minimum value. Simulation and laboratory results show the success of this technique in reducing the inrush current. This technique gives the freedom to the operational engineering for energizing the power transformer at any time.
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Amir Tokić and Ivo Uglešić. "Power Quality Problems Due to Transformer Inrush Current." Journal of Energy - Energija 59, no. 1-4 (2022): 11–18. http://dx.doi.org/10.37798/2010591-4272.
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Transformer energization can produce a large nonsinuoidal inrush current which contains both odd and higher order harmonic components that can put transformer winding under mechanical stress. Additionally, they can cause irregular tripping of harmonic protection relays. Furthermore, in relatively weak power systems, such as is the Bosnian system, the superposition of harmonic components with system resonance frequencies may produce temporary overvoltages (TOV). Transformer winding failures and metal oxide surge arrester (MOA) energy stresses can occur due to TOV. The paper demonstrates a case study of an energization of a 220/110 kV transformer and power quality problems that can appear due to higher harmonics. Energy stresses of MOA provoked by transformer energization are considered in the paper.
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Gunda, Sunil Kumar, and Venkata Samba Sesha Siva Sarma Dhanikonda. "Discrimination of Transformer Inrush Currents and Internal Fault Currents Using Extended Kalman Filter Algorithm (EKF)." Energies 14, no. 19 (2021): 6020. http://dx.doi.org/10.3390/en14196020.
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The discrimination of inrush currents and internal fault currents in transformers is an important feature of a transformer protection scheme. The harmonic current restrained feature is used in conventional differential relay protection of transformers. A literature survey shows that the discrimination between the inrush currents and internal fault currents is still an area that is open to research. In this paper, the classification of internal fault currents and magnetic inrush currents in the transformer is performed by using an extended Kalman filter (EKF) algorithm. When a transformer is energized under normal conditions, the EKF estimates the primary side winding current and, hence, the absolute residual signal (ARS) value is zero. The ARS value will not be equal to zero for internal fault and inrush phenomena conditions; hence, the EKF algorithm will be used for discriminating the internal faults and inrush faults by keeping the threshold level to the ARS value. The simulation results are compared with the theoretical analysis under various conditions. It is also observed that the detection time of internal faults decreases with the severity of the fault. The results of various test cases using the EKF algorithm are presented. This scheme provides fast protection of the transformer for severe faults.
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Wang, Chen, Jianlin Li, Rigao Shu, Cheng Xie, Zheng Cao, and Zhiwei Chen. "Fast calculation and analysis of excitation inrush current peak of converter transformer under different remanence conditions." Advances in Engineering Technology Research 9, no. 1 (2024): 846. http://dx.doi.org/10.56028/aetr.9.1.846.2024.
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In order to solve the problems of fixed model parameters and low efficiency in the traditional numerical method and software simulation method for transformer excitation inrush current. In this paper, the response surface fitting method is applied to the calculation of the excitation inrush current, which realizes the efficient calculation and analysis of the peak value of the excitation inrush current with the change of the closing Angle under the condition of different remanence of the main column. Firstly, the generation mechanism of transformer excitation inrush current was theoretically analyzed, and the key influencing factors were extracted. Secondly, parameter modeling is used to establish the converter transformer model in this paper. Finally, the response surface model between initial winding current, closing Angle and excitation inrush current peak was fitted by response surface test design, and the accuracy of the response surface was verified. It provides technical reference for the fast calculation and analysis of transformer excitation inrush current and the digital twin technology of power transformer.
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Taha, Hussein A. "Eliminating Inrush Current in Three-Phase Transformer using Artificial Neural Network." Wasit Journal of Engineering Sciences 12, no. 4 (2024): 52–63. https://doi.org/10.31185/ejuow.vol12.iss4.568.
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Transformers are important parts of an electrical power system. When a power transformer is connected to the grid, usually inrush current increases substantially with a high value of harmonic components with a duration up to many cycles. The amount of flux in the core increases causing the magnetic circuit to saturate due to the increasing in the load. This paper describes a technique to accurately predict the inrush current and third harmonic of three phase transformer. A shallow neural network was created. The input parameters of the artificial neural network were the magnetization resistance Rm, the initial flux of phase A and the switching angle q. The number of neurons has been changed in the code to see the best performance value. The best validation performance was at epoch 71 with a value of 5.3641e-05. A good prediction results were obtained using this ANN. The simulation of the inrush current was done using the MATLAB Simulink software.
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Li, Jia, Xi, and Chen. "Mechanism Analysis of Sympathetic Inrush in Traction Network Cascaded Transformers Based on Flux-Current Circuit Model." Energies 12, no. 21 (2019): 4210. http://dx.doi.org/10.3390/en12214210.
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When electric multiple units (EMU) pass the neutral zone, the traction transformer may generate sympathetic inrush, which will cause a malfunction in the transformer differential protection. In order to study the mechanism of the sympathetic inrush of the cascaded traction transformer, the flux–current model of the transformer, line impedance, power system voltage source, and other loads was established. On the basis of the flux–current circuit model, the influence of different factors on the sympathetic inrush of the traction transformer was analyzed. The analysis results were verified by simulation. Research results show that the remanence, closing angle, line impedance, and load will affect the duration and amplitude of the sympathetic inrush.
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Li, Chunyan, Yi Yang, Wenyan Li, and Haixiao Li. "A Soft-Start-Based Method for Active Suppression of Magnetizing Inrush Current in Transformers." Electronics 12, no. 14 (2023): 3114. http://dx.doi.org/10.3390/electronics12143114.
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The occurrence of high-amplitude magnetizing inrush current during the energization of a transformer without load poses significant challenges to the stable operation of both the transformer and the power grid, potentially leading to malfunctions in relay protection devices. This paper analyzes the underlying mechanisms of transformer inrush current and presents a novel approach utilizing a soft-start-based method for effectively suppressing inrush currents. The proposed method employs an inrush current suppressor comprising anti-parallel thyristors and filters to mitigate the adverse effects caused by the inrush current. A comparative study is conducted to evaluate the filtering efficacy of three types of filters incorporated in the inrush current suppressor: an LCLC damping filter, a high-order single trap filter and a high-order double trap filter. Through careful analysis and optimization, the high-order double trap filter with parallel RC damping damper is selected as the optimal configuration. To ensure effective suppression, it is necessary to incorporate a filter at the termination point of the anti-parallel thyristor. Additionally, a closed-loop control strategy is implemented to ensure a smooth start and actively suppress the magnetizing inrush current. To validate the effectiveness of the proposed method, comprehensive simulations are performed using Matlab/Simulink. The results demonstrate the successful suppression of inrush current and the maintenance of stable operation for the transformer. This inrush suppression method does not require considering the influence of residual magnetism and the grounding mode of the transformer’s neutral point. It is also suitable for various transformer structures and wiring methods, which makes it highly applicable.
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Sun, Guo Feng. "Analysis of HZD Series Single-Phase Transformer Inrush Current Suppression Method." Applied Mechanics and Materials 341-342 (July 2013): 1412–17. http://dx.doi.org/10.4028/www.scientific.net/amm.341-342.1412.
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Transformer inrush current generated has been plagued by engineering and technical personnel, is also a hot topic in the industry. Electro slag furnace is a common metallurgical industry furnace, used in the metal crystal more closely requirements, performance requirements and a variety of high quality roll alloys, high temperature alloys, nonferrous alloys. Electro slag furnace transformer is the core component, have a great no-load closing inrush current protection trip often makes itself affect the product quality and production efficiency or to expand on a power trip protection range. In order to suppress inrush current, with the primary winding series resistance speed-load closing the attenuation of inrush current, inrush current generated from the theoretical reasons to be discussed and a simple series resistance deduce the resistance of this method. Theoretical basis for comparison with other methods are not subject to a number of objective factors sufficient interference, the results demonstrate the practical application of this method is simple and inrush current suppression effect is very significant. Thus, the series resistance ESR furnace transformer inrush current suppression is a method of high cost.
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Martínez-Figueroa, G. de J., Felipe Córcoles-López, and Santiago Bogarra. "FPGA-Based Smart Sensor to Detect Current Transformer Saturation during Inrush Current Measurement." Sensors 23, no. 2 (2023): 744. http://dx.doi.org/10.3390/s23020744.
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Current transformer saturation affects measurement accuracy and, consequently, protection reliability. One important concern in the case of overcurrent protections is the discrimination between faults and inrush current in power transformers. This paper presents an FPGA-based smart sensor to detect current transformer saturation, especially during inrush current conditions. Several methods have been proposed in the literature, but some are unsuitable for inrush currents due to their particular waveform. The proposed algorithm implemented on the smart sensor uses two time-domain features of the measured secondary current: the second-order difference function and the third-order statistic central moment. The proposed smart sensor presents high effectiveness and immunity against noise with accurate results in different conditions: different residual flux, resistive burdens, sampling frequency, and noise levels. The points at which saturation starts are detected with an accuracy of approximately 100%. Regarding the end of saturation, the proposed method detects the right ending points with a maximum error of a sample. The smart sensor has been tested on experimental online and real-time conditions (including an anti-aliasing filter) with accurate results. Unlike most existing methods, the proposed smart sensor operates efficiently during inrush conditions. The smart sensor presents high-speed processing despite its simplicity and low computational cost.
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Wuyun, Gao Wa. "An Optimization Algorithm of Inrush Currents Inhibition of Closing Time." Applied Mechanics and Materials 475-476 (December 2013): 996–1000. http://dx.doi.org/10.4028/www.scientific.net/amm.475-476.996.
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To meet the complex electromagnetic environmental conditions of power transformer on-site, an optimization algorithm of the closing time based on fuzzy reasoning is proposed. It can not only improve the robustness and stability of inrush currents inhibition of algorithm, but also can be a theoretical basis for the research of transformer inrush current restraining method.
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Namdari, Farhad, Mohammad Bakhshipour, Behroz Rezaeealam, and Mohammad Sedaghat. "Modeling of Magnetizing Inrush and Internal Faults for Three-Phase Transformers." International Journal of Advances in Applied Sciences 6, no. 3 (2017): 203. http://dx.doi.org/10.11591/ijaas.v6.i3.pp203-212.
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Among the most noticeable root causes of improper performance in power transformers, internal short circuit faults can be noted and if not quickly be identified and addressed in the accepted time interval, irrecoverable damages such as interruption or even collapse of the network connected to the power transformer would happen. In this contribution, three-phase transformer behaviors under magnetizing inrush, internal short circuit condition and their current values determination have been surveyed using electromagnetic coupling model approach and structural finite element method. Utilizing the definition of transformer in the form of multi-coil and their electromagnetic and electric couple, a three dimensional geometric model of transformer is developed which includes nonlinear characteristics of the transformer, different states of normal and under internal short circuit occurrence and the moment of magnetizing inrush creation are investigated. The comparison between obtained results of presented model simulation with the consequences of practical studies on a typical three phase transformer reveals that the proposed model has a reliable accuracy in detection and modelling the transformer behavior in normal conditions, magnetizing inrush and different types of internal faults. The proposed approach represents an accurate model of a three-phase transformer for protection aims.
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Bakhshipour, Mohammad, Farhad Namdari, and Mohammad Sedaghat. "Modeling of Magnetizing Inrush and Internal Faults for Three-phase Transformers." Indonesian Journal of Electrical Engineering and Computer Science 3, no. 1 (2016): 26. http://dx.doi.org/10.11591/ijeecs.v3.i1.pp26-37.
Full textAbstract:
Among the most noticeable root causes of improper performance in power transformers, internal short circuit faults can be noted and if not quickly be identified and addressed in the accepted time interval, irrecoverable damages such as interruption or even collapse of the network connected to the power transformer would happen. In this contribution, three-phase transformer behaviors under magnetizing inrush, internal short circuit condition and their current values determination have been surveyed using electromagnetic coupling model approach and structural finite element method. Utilizing the definition of transformer in the form of multi-coil and their electromagnetic and electric couple, a three dimensional geometric model of transformer is developed which includes nonlinear characteristics of the transformer, different states of normal and under internal short circuit occurrence and the moment of magnetizing inrush creation are investigated. The comparison between obtained results of presented model simulation with the consequences of practical studies on a typical three phase transformer reveals that the proposed model has a reliable accuracy in detection and modelling the transformer behavior in normal conditions, magnetizing inrush and different types of internal faults. The proposed approach represents an accurate model of a three-phase transformer for protection aims.
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Komarzyniec, Grzegorz. "Calculating the Inrush Current of Superconducting Transformers." Energies 14, no. 20 (2021): 6714. http://dx.doi.org/10.3390/en14206714.
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Under certain circumstances, after connecting a superconducting transformer to the power network, a high value current may flow through its windings. This current can exceed the critical value of the superconductor many times and cause the windings to lose their superconductive state. Loss of superconductive state of the windings may result in thermal interruption of their continuity as a result of conduction of a current of very high density. The mathematical relationships used to calculate the inrush current of conventional transformers do not work well for the calculation of superconducting transformers. This is due to the properties of superconducting materials used in the windings, first of all to the stepwise changes of the windings’ resistance when exiting the superconducting state and when returning to this state. The article presents the mathematical dependencies allowing to calculate the pulse waveforms of the inrush current of these transformers are derived. Basic electrical circuit sizes are used in the calculations, making the calculations quick and easy. Using the formulas, calculations of the inrush current of 8.5 kVA and 13.5 kVA superconducting transformers. The results were verified with the results of the inrush current measurements, achieving good compliance.
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Yang, Xuemei, Hanjiang Li, Yingqian Ni, Bowen Deng, and Tingting Ren. "Adaptability Analysis of Differential Protection for Output Transformers in Wind Power Plants." Journal of Physics: Conference Series 2785, no. 1 (2024): 012090. http://dx.doi.org/10.1088/1742-6596/2785/1/012090.
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Abstract After large-scale integration of wind farms into the power grid, according to the requirements of the State Grid’s wind power grid connection operation guidelines, wind farms should have low-voltage ride-through capability. The short-circuit current of wind farms will have a significant impact on the identification of excitation inrush currents in the transformers sent out by the wind farms, and the saturation of current transformers will also have an impact on differential protection. Analysis shows that after the wind power is connected, the harmonic components contained in the fault current output by the wind farm will cause the second harmonic braking component to malfunction, and there is a risk of transformer differential protection rejecting operation. At the same time, it will make the current transformer more susceptible to saturation, and the saturation of TA will increase the differential current of the transformer, which may cause misoperation of the transformer differential protection.
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Wael Abdulhassan Atiyah. "A Novel Approach for Diagnosing Transformer Internal Defects and Inrush Current Based on 1DCNN and LSTM Deep Learning." Journal of Electrical Systems 20, no. 4s (2024): 2557–72. http://dx.doi.org/10.52783/jes.3163.
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In power systems, power transformer (Pt) protection plays a vital role in ensuring that customers have a reliable power supply. Correctly recognizing inrush currents from internal defects and preventing differential relay malfunctions are two of biggest challenges facing the differential protection of power transformers. Although previous approaches suggested to overcome these issues have promising outcomes, increasing the accuracy and reducing the execution time and complexity of transformer differential relays are still interesting topics for researchers. Accordingly, a new fault diagnostic method based on wavelet transform (WT) and deep learning is introduced in paper. In the proposed approach, Discrete WT is used to extract the features of differential currents, and combined one-dimensional convolutional neural networks and long short-term memory (1DCNN-LSTM)) is applied for classify internal faults from other abnormal events. High accuracy, no need for any thresholds or transformer parameters and fast fault detection are the main advantages of the proposed approach. The simulation results for a 132/11 kV, 63 MVA power transformer approved the proposed method for its ability to accurately differentiate between inrush currents and internal defects after 5 ms, as well as its accuracy for abnormal event classification of about 99.4%.
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Turner, Ryan, and Kenneth Smith. "Transformer Inrush Currents." IEEE Industry Applications Magazine 16, no. 5 (2010): 14–19. http://dx.doi.org/10.1109/mias.2010.937440.
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Bharambe, Purushottam R., Dr Sudhir R. Paraskar, Ravishankar S. Kankale, and Dr Saurabh S. Jadhao. "A Statistical Approach to Discriminate the Magnetising Inrush Current and Internal Fault Current of a Transformer." International Journal for Research in Applied Science and Engineering Technology 10, no. 8 (2022): 1611–18. http://dx.doi.org/10.22214/ijraset.2022.46462.
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Abstract: The transformer is one of the important elements of electrical power system. So, it is required to provide the good protection scheme for transformer, which enhance the reliability & economy of the system. There are many methods available for the protection of transformer out of which differential protection is the most commonly used method. It is observed that the conventional differential protection scheme mal-operates during the magnetizing inrush current. The mal-operation of differential relay will affect the continuity of supply to customer and hence the economy of our system. To avoid such type of mal-operation of the relays, proper discrimination between the magnetising inrush current and fault current is required. This paper presents Teager Energy Operator (TEO) and Statistical parameters based novel approach for the discrimination between the magnetizing inrush current and the internal fault current of a transformer. In this paper, TEO of the differential current of the transformer is calculated and compared with its threshold value to detect the abnormal condition. When TEO is more than threshold, statistical parameters like variance & standard deviation are calculated and if the calculated value is more than the threshold then it’s an internal fault condition and hence relay gives the trip signal. Else relay does not issue the trip signal. The suggested algorithm is tested using the experimental data. The results demonstrated that the suggested algorithms are capable of accurately differentiating between the transformer's internal fault current and inrush current.
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Horiszny, Jacek. "Implementation of power transformer controlled switching algorithm." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 35, no. 4 (2016): 1418–27. http://dx.doi.org/10.1108/compel-01-2016-0007.
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Purpose – The paper presents two new algorithms of controlled switching the power transformer. The purpose of this paper is to obtain formulas that determine the moments of closing of the circuit breaker poles. The study contains projects of control systems for both algorithms. Design/methodology/approach – Mathematical formulas for the time instants of the breaker poles closing were developed on the basis of electric circuit theory and magnetic circuit theory. The presented systems were simulated using a model created in the Alternative Transients Program/Electromagnetic Transients Program software. Findings – Numerical simulations have proved that the shown systems properly perform the controlled switching carried out in accordance with the proposed algorithms. The times of the poles closing were correctly determined and the inrush currents were reduced to a level of the current of unloaded transformer. Originality/value – The results achieved are better than those shown in the literature. The solutions presented in the literature provide a reduction of inrush current to a value comparable to the rated current of the transformer, which is ten times greater than the no-load current. Additional achievement of the work is the development of analytical formulas that determine the times of the breaker poles closing.
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Ganguly, Avishek. "HARMONIC ANALYSIS OF TRANSFORMER’S MAGNETIC INRUSH AND FAULT CURRENT WITH FFT." International Journal of Engineering Applied Sciences and Technology 6, no. 11 (2022): 165–69. http://dx.doi.org/10.33564/ijeast.2022.v06i11.031.
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The distorted voltage or current waveform (not purely sinusoidal) contains harmonics. The frequency of harmonics may be integer multiple or fraction of fundamental frequency. Increase of power electronic loads, faults in power system, switching of induction motors, transformer switching, magnetic saturation of transformers core are several reasons of harmonic pollution.
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Li, Hong Kui. "Analysis of Three-Phase Power Transformer Inrush Current Magnetic Field." Applied Mechanics and Materials 44-47 (December 2010): 1719–23. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.1719.
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This research studies the magnetic field and forces on the windings of transformer due to short circuit. Three dimensional finite element computation of three-phase power transformer is carried out. The model developed have been applied to power transformer and the results are verified experimentally. To verify the computation results, they are compared with those obtained using ANSYS software simulation.
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Zhang, Licheng, Shan Li, and Bing Sun. "Simulated Calculation and Measured Analysis on the Spot with the 750 kV Transformer Switch-In with Load." Journal of Electronic Research and Application 9, no. 1 (2025): 147–56. https://doi.org/10.26689/jera.v9i1.9424.
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Through an example of a main transformer switch-in with load during the reverse transmission of a 750 kV power plan, the paper introduces the basic principle of transformer switch-in with load. EMTPE program that is used to establish a calculation model, at the same time mainly considers the excitation characteristics of the transformer, the transient model of the circuit breaker, and the model of high voltage transformer, and calculated the inrush current with transformer switch-in with load in this plan. During system debugging in the plan, the two sets of main transformers passed the closing and opening test, and the data of inrush current in the test are recorded and analyzed. The simulation calculation and measured data show that the results are consistent. The simulation calculation also shows that it is not recommended to perform on-load closing of the transformer except for special circumstances, because of the influence of hysteresis characteristic when the transformer was switched in with load or the terminal voltage of the transformer resumed normal level from a low one after an external near-end fault was cleared, which various transformer differential protection using the characteristics of inrush to implement block scheme may mal-operate.
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ABDELMOUMENE, Abdelkader, Rachid BOUDERBALA, and Hamid BENTARZI. "Design and Evaluation of a DSP Based Differential Relay of Power Transformer." Algerian Journal of Signals and Systems 1, no. 1 (2021): 69–78. http://dx.doi.org/10.51485/ajss.v1i1.20.
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The problem of mal operation of differential protection of power transformer due to the inrush magnetizing current has long considered as a challenging problem. Several types of protection relays have been used to solve the issue (basic relay, percentage relay, multi slop ….). Each of them has its advantage and its limits. In this paper, a Digital differential relay has been developed and simulated. The logic used to distinguish between the inrush current and the internal fault is based on the theory of harmonic analysis. The behavior of the presented relay has been simulated versus various situations (inrush current, internal fault and external fault). The obtained results show that the proposed algorithm provides a good discrimination and a fast action.