Magnetic Shunt Design and Their Effects on Transformer Winding Electromagnetic Forces

Wang, Yuxing; Zhang, Jiangong; Zhou, Bing; Wang, Yanzhao; Yuan, Naichang

doi:10.1007/s40998-018-0074-4

Cited by 8 publications

(3 citation statements)

References 15 publications

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“…Various standards recommended maximum permissible magnetic field intensity, which is 20 µT for 2 kV/m conductor. Furthermore, international guidelines enforce maximum field intensity of 0.8 µT at 50 Hz frequency in the context of human health [ 21 , 22 ]. Due to high permeability, Mu-metal and electrical steel (Fe-Si alloy) are used as flux shunting materials.…”

Section: Introductionmentioning

confidence: 99%

Manufacturing of Pure Iron by Cold Rolling and Investigation for Application in Magnetic Flux Shielding

Satpute¹,

Dhoka²,

Iwaniec

et al. 2022

Materials

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The presented work investigates a novel method to manufacture 98.8% pure iron strips having high permeability and better saturation flux density for application in magnetic flux shielding. The proposed method uses electro-deposition and cold rolling along with intermediate annealing in a controlled environment to manufacture 0.05–0.5 mm thick pure iron strips. The presented approach is inexpensive, has better control over scaling/oxidation and requires low energy than that of the conventional methods of pure iron manufacturing by pyrometallurgical methods. Important magnetic and mechanical properties of the pure iron are investigated in the context of the application of the material in magnetic shielding. Magnetic properties of the material are investigated by following IEC60404-4 standard and toroidal coil test to determine hysteresis curve, magnetic permeability and core losses. The microstructure is investigated with an optical microscope and scanning electron microscopy to study grain size and defects after cold rolling and annealing. The properties derived from the experimental methods are used in finite element analysis to study the application of the material for static, low-frequency and high-frequency magnetic shielding. Theoretical simulation results for magnetic shielding around a current-carrying conductor and micro-electromechanical inductive sensor system are discussed. Further shielding performance of the material is compared with that of the other candidate materials, including that of Mu-metal and electrical steel. It is demonstrated that the pure iron strips manufactured in the present study can be used for magnetic shielding in the case of low-frequency applications. In the case of high-frequency applications, a conducting layer can be combined to ensure the required shielding effectiveness in the case of Class 2 applications.

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Section: Introductionmentioning

confidence: 99%

Manufacturing of Pure Iron by Cold Rolling and Investigation for Application in Magnetic Flux Shielding

Satpute¹,

Dhoka²,

Iwaniec

et al. 2022

Materials

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show abstract

“…In a large electric power system, the currents in electrical apparatuses such as transformers increase as a result of higher loading in the power transformers, which increases the electromagnetic forces produced [8], [9]. Furthermore, because electromagnetic forces are proportional to the square of the current flowing through the transformer windings, mechanical stress and mechanical oscillations on the windings are significantly increased in the event of a short circuit or inrush current [10], [11].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Transformer Vibration Characteristics using the Finite Element Method

Samimi

2022

Scientia Iranica

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Understanding the vibrational characteristics of power transformers is significantly important in their design and monitoring. In this contribution, a model with a multi-physics coupling simulation of the electrical circuit, magnetic field, and solid mechanics is developed to investigate the characteristics of the transformer vibration. After describing the model, the harmonic contents of the vibration signals and their variation in the case of mechanical faults are studied. It is shown that under normal operating conditions, the fundamental vibration frequency of 100 Hz has the maximum amplitude, while in the case of mechanical faults, the amplitudes of 200 Hz and 300 Hz harmonics increase dramatically compared to the fundamental harmonic. The influence of vibration sensor position is investigated too, which indicates that the area near the tank bottom is the best position to gather vibration signals. Moreover, the mechanical resonance frequencies of the transformer, along with their mode shapes, are addressed in this paper. Finally, the influence of mechanical changes on the vibration energy distribution in the tank surface is explored. The results of the paper suggest possible diagnosis methods for condition monitoring of transformers, such as using the vibration energy distribution on the tank surface or analyzing the vibration harmonics.

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“…Refs. [12][13][14][15] analyzed the transient electromagnetic forces of large power transformer windings under shortcircuit currents. A three-dimensional transformer electromagnetic-structural coupling finite element model was established to analyze the dynamic electromagnetic force and winding mechanical structure interaction during short-circuit condition, and the simulation analysis results were compared with the experimental results.…”

Section: Introductionmentioning

confidence: 99%

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

Zhang

Xie

et al. 2021

Energies

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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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Magnetic Shunt Design and Their Effects on Transformer Winding Electromagnetic Forces

Cited by 8 publications

References 15 publications

Manufacturing of Pure Iron by Cold Rolling and Investigation for Application in Magnetic Flux Shielding

Manufacturing of Pure Iron by Cold Rolling and Investigation for Application in Magnetic Flux Shielding

Investigation of Transformer Vibration Characteristics using the Finite Element Method

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

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