Effect of BTA on Interface Charge Barrier and Charge Transportation in Oil-paper Insulation

Gao, Lu; Wu, Yang; Lv, Zepeng; Wu, Kai

doi:10.1109/tdei.2022.3157891

Cited by 9 publications

(9 citation statements)

References 25 publications

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“…The relative dielectric constant of the insulating oil system is 2.16. This is consistent with the dielectric constant ε r = 2.27 measured in engineering practice …”

Section: Resultssupporting

confidence: 91%

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Calculation of Charge Transport Phenomena and Mobility Analysis in the Insulating Oil Using First Principle and Marcus Theory

Chen,

Liu,

Maharana

et al. 2024

J. Phys. Chem. B

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Oil-paper insulation is widely used as a reliable composite insulation system in power transformers. The dielectric property of oil insulation plays an important role in the reliable operation of power equipment. To recognize the charge transfer process in composite insulation, the mobility of the charge in aged insulating oil is studied. However, few studies have been conducted on the microscopic mechanism of charge transport phenomena at the molecular level. In this research, we have studied the molecular electronic structure and the distribution of holes and electrons in the insulating oil by first-principles calculation. By combining with Marcus theory, the corresponding electron coupling energy, reorganization energy, and free energy are obtained. The corresponding charge hopping model is chosen by the parameter relation, and the hopping rate is calculated. At last, the mobility of holes and electrons in insulating oil within the insulation is simulated by the Monte Carlo method. Other possible charge migration methods are also studied and discussed for the comparison. It is observed that the transfer integral of electrons is 2 orders of magnitude larger than that of holes, which is mostly due to the localization of lowest unoccupied molecular orbitals (LUMO). The hole and charge transfers accord with Marcus hopping, the adiabatic charge transfer model, and the charge hopping rate is obtained. The actual free energy action under an external electric field is obtained by calculating polarizability and permittivity. Monte Carlo simulation is used to obtain the charge transfer image and mobility under an actual electric field. Possible types of traps and mobility of ions and clusters in the insulating oil are also studied.

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“…The relative dielectric constant of the insulating oil system is 2.16. This is consistent with the dielectric constant ε r = 2.27 measured in engineering practice …”

Section: Resultssupporting

confidence: 91%

“…This is consistent with the dielectric constant ε r = 2.27 measured in engineering practice. 45 The external free energy caused by electrostatic interaction is estimated by the dipole moment μ B .…”

Section: ■ Resultsmentioning

confidence: 99%

Calculation of Charge Transport Phenomena and Mobility Analysis in the Insulating Oil Using First Principle and Marcus Theory

Chen,

Liu,

Maharana

et al. 2024

J. Phys. Chem. B

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“…However, oil−paper interfaces exhibit remarkable charge accumulation under a relatively low electric field, 4−6 which aggravates the distortion of the local electric field distribution and further threatens the reliability of the insulation system. 7,8 In the traditional dielectric polarization theory, interface charges follow the Maxwell−Wagner−Sillar (MWS) polarization model. That is, interface charge accumulation comes from the discontinuity of the ratio of conductivity to the dielectric constant of materials on different sides of the interface.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The basic configuration of oil–paper insulation is a composite structure of overlapping insulating paper and insulating oil gap, forming a large number of oil–paper interfaces. , In homogeneous solid materials, charge accumulation can be observed only under a high electric field. However, oil–paper interfaces exhibit remarkable charge accumulation under a relatively low electric field, − which aggravates the distortion of the local electric field distribution and further threatens the reliability of the insulation system. , …”

Section: Introductionmentioning

confidence: 99%

Probing and Modulation of the Electric Double Layer at the Insulating Oil–Paper Interface

Gao,

Chen,

et al. 2023

Langmuir

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“…oil-paper interface is a common phenomenon that can be observed in various space charge experiments, including those involving different electric fields [5], ageing conditions [6][7][8][9], and impregnation patterns on the oil-paper insulation [10]. This charge distribution and accumulation near the oil-paper interface were explained by the formation of an electric double layer (EDL) [11] or surface potential barrier [12] across the interface. Furthermore, Zhu et al proposed an empirical model explaining charge transport behaviour in oil-paper insulation under temperature gradients based on bipolar carrier transport and trap barrier theory [13].…”

mentioning

confidence: 99%

Dynamics of an impurity ion transport in oil‐paper insulation under various electric fields

Ren,

Wang,

Zhang

et al. 2023

High Voltage

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The ionic transport process is an important counterpart to charge transport in oil‐paper insulation, and it significantly impacts oil flow electrification at the oil‐paper interface. Despite this, the dynamics of this phenomenon and the underlying mechanisms remain unclear, particularly at the molecular level. To understand this fundamental aspect, we conduct Molecular Dynamics study on the transport behaviour of an impurity ion in different oil‐paper insulation models under various external electric fields. Different influence factors, such as external electric fields, temperatures, and local structural characteristics, are investigated in relation to the corresponding ionic mobility in different polymer models. According to the simulations, ionic mobility and its response to electric fields are higher in weaker electrostatic models. As a result, mineral oil exhibits the highest ionic mobility and the most substantial enhancement of ionic mobility by external electric fields, followed by vegetable oil, oil‐paper blends, and insulating paper. This significant deviation in ionic mobility between oil and paper leads to the formation of an electric double layer near the oil‐paper interface. The underlying physical mechanisms of different ionic mobility and its response to the electric field in different polymer models could be explained by the different polymer structural influences in terms of interaction energy and coordination numbers in a static manner, as well as by the interactions between the impurity ion and its surrounding atoms in terms of lifetime correlation functions and velocity autocorrelation functions in a dynamic manner. In addition, the influence of temperature on ionic mobility in mineral and vegetable oil is examined, and their activation energies are calculated. Advancing in the fundamental understanding of the dynamics of the ion transport process in oil‐paper insulation is vital to improving their insulating properties for oil‐impregnated power transformers.

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Effect of BTA on Interface Charge Barrier and Charge Transportation in Oil-paper Insulation

Cited by 9 publications

References 25 publications

Calculation of Charge Transport Phenomena and Mobility Analysis in the Insulating Oil Using First Principle and Marcus Theory

Calculation of Charge Transport Phenomena and Mobility Analysis in the Insulating Oil Using First Principle and Marcus Theory

Probing and Modulation of the Electric Double Layer at the Insulating Oil–Paper Interface

Dynamics of an impurity ion transport in oil‐paper insulation under various electric fields

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