Estimating the Amplitude of Power Transformer Magnetizing Inrush Currents Caused by Geomagnetic Disturbances

2021 ◽  
Author(s):  
A. A. Kuvshinov ◽  
V. V. Vakhnina ◽  
A. N. Chernenko
Keyword(s):  
Power Transformer ◽  
Geomagnetic Disturbances ◽  
Inrush Currents

Evaluation of the Power Transformer Magnetizing Inrush Currents

2020 ◽  
Vol 10 (10) ◽  
pp. 20-32
Author(s):  
Aleksey A. KUVSHINOV ◽  
◽  
Vera V. VAKHNINA ◽  
Aleksey N. CHERNENKO ◽  
◽  
...  
Keyword(s):  
Power Transformer ◽  
Geomagnetic Disturbance ◽  
Inrush Current ◽  
Geomagnetic Disturbances ◽  
Disturbance Intensity ◽  
Magnetizing Inrush Current ◽  
Inrush Currents ◽  
Instantaneous Values ◽  
The Mathematical Model ◽  
Analytical Expressions

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.

A Novel Approach for Classifying Transient Phenomena in Power Transformers

2004 ◽  
Vol 1 (2) ◽  
Author(s):  
El Sayed M. Tag Eldin
Keyword(s):  
Fuzzy Logic ◽  
Wavelet Transforms ◽  
Power Transformer ◽  
Current Transformer ◽  
Transient Phenomena ◽  
Protective Relay ◽  
Novel Approach ◽  
Inrush Currents ◽  
Internal Faults ◽  
External Faults

The role of a power transformer protective relay is to rapidly operate the tripping during internal faults and block the tripping during magnetizing inrush. This paper presents a new approach for classifying transient phenomena in power transformer, which may be implemented in digital relaying for transformer differential protection. Discrimination between internal faults, external faults with current transformer saturation and magnetizing inrush currents is achieved by combining wavelet transforms and fuzzy logic. The wavelet transform is applied for the analysis of the power transformer transient phenomena because of its ability to extract information from the transient signals in both time and frequency domain. Fuzzy logic is used because of the uncertainty in the differential current signals and relay settings. MATLAB power system toolbox is used to generate current signals at both sides of a power transformer in a typical system with various conditions. The simulation results obtained show that the new algorithm provides a high operating sensitivity for internal faults and remains stable for external faults and inrush currents.

scholarly journals Analysis of the Electromechanical Characteristics of Power Transformer under Different Residual Fluxes

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8244
Author(s):  
Wenqi Ge ◽  
Chenchen Zhang ◽  
Yi Xie ◽  
Ming Yu ◽  
Youhua Wang
Keyword(s):  
Power Transformer ◽  
Input Parameter ◽  
Electromagnetic Transients ◽  
Structural Parameter ◽  
Inrush Current ◽  
Parameter Variations ◽  
Inrush Currents ◽  
3D Finite Element Method ◽  
Opening And Closing ◽  
The Impact

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.

scholarly journals Simulink model of transformer differential protection using phase angle difference based algorithm

2020 ◽  
Vol 11 (2) ◽  
pp. 1088
Author(s):  
Nassim A. Iqteit ◽  
Khalid Yahya
Keyword(s):  
Phase Angle ◽  
Power Transformer ◽  
Inrush Current ◽  
Current Transformers ◽  
Phase Angle Difference ◽  
Simulink Model ◽  
Magnetizing Inrush Current ◽  
Angle Difference ◽  
Inrush Currents ◽  
Transformer Differential Protection

<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>

A suggested differential protection scheme for power transformer

2014 ◽  
Vol 5 (2) ◽  
pp. 91-103 ◽  
Author(s):  
E. Ahmed ◽  
R. El-Sehiemy
Keyword(s):  
High Speed ◽  
Power Transformer ◽  
Normal Operation ◽  
Power Differential ◽  
Transformer Protection ◽  
Protection Scheme ◽  
Wide Range ◽  
Inrush Currents ◽  
Differential Scheme ◽  
External Faults

This paper integrates a Real Power Differential Scheme (RPDS) for power transformer protection. The suggested RPDS for power transformer computes the active power loci during normal operation, switching, normal, and internal, involves turn to turn, and external faults at varied load angles. The proposed RPDS concept is based on monitoring and comparing the transformers primary and secondary active and reactive powers. The dynamic response of the proposed RPDS is tested 300 MVA, 220/66 kV, Y/Δ transformer. Furthermore, the suggested scheme is simulated with the use of Matlab/Simulink then tested for various fault and switching conditions. Moreover, the RPDS is checked for inter turn fault conditions at primary and secondary sides. The evaluation of the suggested scheme confirms the superiority of the proposed scheme to distinguish internal and external faults as well as magnetizing inrush currents with good selectivity, high speed, sensitivity, stability limits and high accuracy response of the power differential scheme. Finally, the suggested scheme is able to detect correctly the turn to turn faults for wide range of fault resistances but fails at very low values.

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