Moisture‐dependent interface and bulk behaviour of space charge in DC‐stressed oil‐impregnated pressboard insulation

Zhou, Guiyue; Wu, Jiandong; Che, Lu; Yin, Yi

doi:10.1049/gtd2.12043

Cited by 8 publications

(4 citation statements)

References 28 publications

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“…When the electric field is higher than 1 kV mm −1 , the charge was injected into the cellulose paper and participated in the transport process. 57 As analyzed above, the i p − i d results were not a constant and flat straight line due to the trapped charge, and this feature became more significant with the continuous increase in the electric field. Herein, the results under 5 kV mm −1 were taken as an example for detailed analysis.…”

Section: Journal Of Applied Physicsmentioning

confidence: 81%

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Mechanism study of the conductivity characteristics of cellulose electrical insulation influenced by moisture

Zhao

Zhang

et al. 2022

Journal of Applied Physics

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Cellulose insulating paper is widely used in the power industry for its good electrical insulating properties. Moisture sharply increases its conductivity, which directly leads to the weakening of insulation performance and greatly increases the risk of subsequent electric field distortion and insulation breakdown. This paper focuses on the microscopic mechanism of moisture changing the characteristics of charge transport in cellulose insulation and attempts to reveal the related conductivity mechanism. To achieve this purpose, microscopic and macroscopic perspectives are integrated and several simulation and experimental methods are utilized comprehensively. The molecular dynamics simulation results showed that most water molecules in damped cellulose were individually and uniformly adsorbed on the hydroxyl groups by hydrogen bond, and the quantum chemistry computation results showed that the lowest unoccupied molecular orbital more appeared on the water molecule and the corresponding density of state increased. Then, experimentally, it was confirmed that the trap energy level decreased by the thermally stimulated current method. On this basis, the promotion effect of moisture on charge transport is predicted and verified by polarization and depolarization current methods. As the moisture content increased, more charge carriers escaped from the trap by hopping and participated in long-range continuous charge motion. Therefore, after dampness, the current of cellulose insulating paper increased exponentially with the increase in electric field strength, which was consistent with the hopping conductivity mechanism.

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Section: Journal Of Applied Physicsmentioning

confidence: 81%

“…This charge transport characteristic of the cellulose paper under the influence of moisture is consistent with the accumulation and dissipation characteristics of space charge obtained by the pulse electro-acoustic (PEA) method. 57 2. The conductivity mechanism of cellulose insulating paper under the influence of moisture…”

Section: Journal Of Applied Physicsmentioning

confidence: 99%

Mechanism study of the conductivity characteristics of cellulose electrical insulation influenced by moisture

Zhao

Zhang

et al. 2022

Journal of Applied Physics

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show abstract

“…In this paper, the parameters used in this numerical simulation are based on [24,25], and the model parameters are listed in Table 3. By using parameters in Table 3, a numerical simulation is conducted to obtain the space charge curve, as shown in Figure 6a.…”

Section: Effects Of Moisture Contentmentioning

confidence: 99%

“…The relationship between the maximum value of heterocharge density and the thickness of oil-impregnated paper (x) is shown in Figure 11. The fitting equation of the curve in Figure 11 can be expressed by (24). The fitting degree is 0.99.…”

Section: Effects Of the Thickness Of Oil-impregnated Papermentioning

confidence: 99%

Effect of multi‐factors on heterocharges for oil‐impregnated paper in converter transformer using modified charge transport model

Yan

Liu

Fan

et al. 2021

IET Generation Trans & Dist

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The heterocharge accumulated in the oil-paper insulation system of the converter transformer will enhance the local electric field and cause insulation deterioration. Numerical simulation is an effective method to analyze heterocharge. Currently, the numerical simulation of heterocharge is mainly based on the bipolar charge transport (BCT) model and the impurity ion transport (IIT) model. However, the effects of temperature, conductivity, and thickness of oil-impregnated paper on charge transport have not been considered in these models. In view of this, a modified charge transport (MCT) model by introducing the Maxwell-Wagner model and heat conduction equation is proposed in this paper based on the BCT model and IIT model. Then, the influence of multi-factors (temperature gradient, moisture content, and oil-impregnated paper thickness) on heterocharge accumulation is investigated by using the MCT model. The simulation results obtained by the MCT model are more consistent with the experimental results than the BCT model, which proves the accuracy and superiority of the MCT model. Moreover, the increase in temperature gradient, moisture content, and oil-impregnated paper thickness will enlarge the ion dissociation rate, conductivity, and trap density, and thus promote the generation of heterocharge. In that respect, the MCT model is expected to optimize the insulation design and provide a reference for space charge dynamic simulation.

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Interface Charge Characteristics in Polymer Dielectric Contacts: Analysis of Acoustic Approach and Probe Microscopy

Wang

et al. 2023

Adv Materials Inter

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Interfaces are essential components in polymer contact systems, which widely exist in electronic devices and power equipment. Interface charge originating from the mismatch of the electronic structure in interfaces is one of the key issues to modify the device performance due to its multifunctional migration and accumulation behaviors. Hence, the detection and analysis of the interface charge characteristics are of great importance to deeply understand the polymer contact system in various devices. This paper presents an overview of recent research progress in the interface charge properties at dielectric interfaces. Based on the theoretical analysis of the MWS polarization and electronic localized states, two typical approaches of discussing the interface charges from micrometer to millimeter are mainly studied. Acoustic method is prevalent in detecting the space charge in various dielectrics. However, owing to its limited resolution (several µm), it is difficult to clarify the charge distributions at the interface with a micro‐scale. Probe microscopy presents a promising technique due to its flexible surface potential detection at a submicron scale. The challenges and prospects of acoustic and probe microscopy methods are discussed in this paper. The advanced techniques of interface charges can promote the development of new energy electronic devices.

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Moisture‐dependent interface and bulk behaviour of space charge in DC‐stressed oil‐impregnated pressboard insulation

Cited by 8 publications

References 28 publications

Mechanism study of the conductivity characteristics of cellulose electrical insulation influenced by moisture

Mechanism study of the conductivity characteristics of cellulose electrical insulation influenced by moisture

Effect of multi‐factors on heterocharges for oil‐impregnated paper in converter transformer using modified charge transport model

Interface Charge Characteristics in Polymer Dielectric Contacts: Analysis of Acoustic Approach and Probe Microscopy

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