Residual Flux Measurement of the Single-Phase Transformer Based on Transient Current Method

Huo, Cailing; Wang, Youhua; Zhao, Ziwei; Liu, Chengcheng

doi:10.1109/tasc.2020.2975192

Cited by 17 publications

(7 citation statements)

References 4 publications

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“…Based on the magnetic circuit analysis [25], the relationship between the equivalent inductance Leq and μrd at Br is expressed as = 2 0 (5) where N expresses the ratio of measuring winding, S and l represent the cross-sectional area and the average magnetic path length of the iron core, respectively. μ0 expresses the vacuum permeability of air, and its value is 4π×10 -7 H/m.…”

Section: Determining Direction Of Residual Flux Densitymentioning

confidence: 99%

“…However, this method uses the magnetization curve in the simulation model, thus this accuracy is greatly reduced and the Br direction is not judged. To address the limitations of this approach, in [25], author analyzes the relationship between Br and transient current difference. However, the measurement time of transient current difference is not easily determined, which may result in a lower accuracy of calculated Br.…”

Section: Introductionmentioning

confidence: 99%

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Residual Flux Density Measurement Method of Single-Phase Transformer Core Based on Time Constant

Huo

Yang

et al. 2020

IEEE Access

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Residual flux density in the single-phase transformer core can dramatically increase inrush current when the transformer is energized. To reduce inrush current, it is necessary to study residual flux density measurement. This paper proposes a new residual flux density measurement method based on time constant. Firstly, the generation principle of residual flux density is analyzed under different magnetization states, and it is found that the positive relative differential permeability is smaller than the negative at different residual flux density. To obtain the relative differential permeability, when an appropriate DC excitation is applied, the measurement circuit is equivalent to a first-order RL circuit. Then, combining magnetic circuit and transient circuit analysis, the relationship between time constant and relative differential permeability is obtained. It is conclusion that the positive time constant is less than the negative. Residual flux density direction is determined by comparing the positive and negative time constant, and the magnitude of residual flux density is calculated by the relationship between residual flux density and the difference of the positive and negative time constant. Finally, the empirical formula between residual flux density and time constant difference of the square core is obtained in finite element method, and then verified on the experimental platform. Compared with other measurement methods, the relative error of proposed empirical formula is within 4.58 %, and it has higher accuracy in this paper. The proposed method in this paper can provide a reference for selecting the demagnetization voltage, which improves the effectiveness of demagnetization. INDEX TERMS Residual flux density, relative differential permeability, time constant difference, empirical formula.

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Section: Determining Direction Of Residual Flux Densitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Residual Flux Density Measurement Method of Single-Phase Transformer Core Based on Time Constant

Huo

Yang

et al. 2020

IEEE Access

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“…However, the existence of the tank of the actual transformer makes the fluxgate unable to get close to the iron core, and the small signal of the leakage flux is sensitive to any kind of possible noise. The remanence can also be obtained according to the empirical equation between the remanence and the measured small voltage and current signals, including amplitude of the transient current difference [12], extremum time of the transient current difference [13], time constant of the transient current [14] and the area of minor hysteresis loop [15]. The determination of the empirical equation requires a lot of experiments or simulations, which is difficult to conduct on such many types of transformers in the actual power system.…”

Section: Introductionmentioning

confidence: 99%

Field‐circuit coupling numerical calculation method of transformer remanence

Yuan

2022

IET Electric Power Appl

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When the transformer is re‐energised, the remanence in the core will cause inrush current, which will have adverse impacts on the power system. In the remanence distribution calculation, not only the hysteresis characteristics of the core, but also the characteristics of the external circuit need to be considered. In this paper, an indirect field‐circuit coupling method for calculating transformer remanence distribution is presented. The residual flux density distribution at every point of the iron core, which has not been shown in previous literatures, can be obtained, and also the H‐B trajectory of the iron core. In the field calculation, the pseudo‐permeability method is modified in order to fit the field separation‐based dynamic hysteresis model. The pseudo‐permeability method and the initial value estimation method are used to speed up the iteration convergence. Furthermore, in the electric circuit topology used in the calculation, the switching process of the circuit breaker and the capacitance in the circuit are considered, and this has not been tried in the previous remanence calculation method. The remanence results are verified by comparison with the results in the literature. The remanence results can provide a basis for the impact analysis and phase control of the re‐energisation.

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“…Finally, the results were verified by experiments. A method for interpreting the residual flux of a single-phase transformer by sequentially applying two Direct Current (DC) voltages of opposite polarity to the transformer windings and then detecting their corresponding transient response currents was proposed in [6]. The equation between the residual flux and the transient current difference was fitted using the data analysis method.…”

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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Residual Flux Measurement of the Single-Phase Transformer Based on Transient Current Method

Cited by 17 publications

References 4 publications

Residual Flux Density Measurement Method of Single-Phase Transformer Core Based on Time Constant

Residual Flux Density Measurement Method of Single-Phase Transformer Core Based on Time Constant

Field‐circuit coupling numerical calculation method of transformer remanence

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

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