The role of trapped space charges in the electrical aging of insulating materials

Dissado, L.A.; Mazzanti, G.; Montanari, Gian Carlo

doi:10.1109/94.625642

Cited by 350 publications

(197 citation statements)

References 28 publications

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“…12 In the past two decades, due to development in mapping the space charge in solid insulation materials, numerous studies have been carried out to pursue a better understanding of the buildup of trapped space charge within solid dielectric materials. [13][14][15][16][17][18][19][20][21] Consequently, our knowledge of space-charge dynamics and the factors that can affect charge formation has enabled us to improve the electrical performance of materials via material selection and processing. However, majority of the work has been carried out under dc conditions; little attention has been given to the effect of ac aging on space-charge formation in the bulk insulation.…”

Section: Introductionmentioning

confidence: 99%

ac aging and space-charge characteristics in low-density polyethylene polymeric insulation

Chen

Liu

et al. 2005

Journal of Applied Physics

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In the present work efforts have been made to investigate the influence of ac aging on space-charge dynamics in low-density polyethylene ͑LDPE͒. LDPE films with 200 µm were aged under various electric stress levels at 50 Hz for various times at ambient temperature. Space-charge dynamics in the samples after aging were monitored using the pulsed electroacoustic technique. It has been revealed that the space charge under ac aging conditions is related to the level of the applied field, duration of the voltage application, as well as the electrode materials. By comparing with the results of unaged sample the results from aged sample provide a direct evidence of changing trapping characteristics after ac aging. Negative space charge is present in the bulk of the material and the total amount of charge increases with the aging time. The amount of charge increases with the applied field. Charge decay test indicates that the charges are captured in deep traps. These deep traps are believed to form during the aging and related to change caused by injected charge. By using different electrode materials such as gold, brass alloy, and polyethylene loaded with carbon black, it was found that the electrode has an important role in the formation of charge, hence subsequent changes caused by charge. The charge dynamics of the aged samples under dc bias differ from the sample without ac aging, indicating changes brought in by ac aging. Chemical analysis by Fourier transform infrared spectroscope and Raman microscope reveals no detectable chemical changes taken place in the bulk of the material after ac aging. Finally, the consequence of the accumulation of space charge under ac conditions on the lifetime of the material has been discussed. The presence of deeply trapped space charge leads to an electric stress enhancement which may shorten the lifetime of the insulation system.

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Section: Introductionmentioning

confidence: 99%

ac aging and space-charge characteristics in low-density polyethylene polymeric insulation

Chen

Liu

et al. 2005

Journal of Applied Physics

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“…How are the nanoholes formed in dielectric materials is currently one of the hotspots in dielectric research. Ageing processes and mechanisms in mesoscopic scale can be described by three theoretical models: the kinetic model suggested by Lewis [24][25][26][27][28][29][30][31][32]; the space-charge life model developed by Dissado and Montanari [33][34][35][36][37][38] and thermodynamic model of molecular presented by Crine [21,[39][40]. Basic descriptions of phenomenon in mesoscopic scale are as follows.…”

Section: The Spatio-temporal Relation Between Ageing Degradation Andmentioning

confidence: 99%

Short-term breakdown and long-term failure in nanodielectrics: a review

Yin

Chen

et al. 2010

IEEE Trans. Dielect. Electr. Insul.

286

166

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Nanodielectrics, which are concentrated in polymer matrix incorporating nanofillers, have received considerable attention due to their potential benefits as dielectrics. In this paper, short-term breakdown and long-term failure properties of nanodielectrics have been reviewed. The characteristics of polymer matrix, types of nanoparticle and its content, and waveforms of the applied voltage are fully evaluated. In order to effectively comment on the published experimental data, a ratio k has been proposed to compare the electric properties of the nanodielectrics with the matrix and assess the effect for nanoparticles doping. There is evidence that the short-term breakdown properties of nanodielectrics show a strong dependence on the applied voltage waveforms. The polarity and the cohesive energy density (CED) of polymer matrix have a dramatic influence on the properties of nanodielectrics. Nanoparticle doped composites show a positive effect on the long-term failure properties, such as ageing resistance and partial discharge (PD) properties of nanocomposites are superior than microcomposites and the matrix. The larger the dielectric constant and CED of the matrix become, the more significant improvements in long-term performance appear. Based on the reported experimental results, we also present our understandings and propose some suggestions for further work.

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“…The forward transition from unaged state to aged state indicates the process of chemical bonds broken, reorganized and reformed into another configuration in insulation materials while the backward transition refers to the reverse reaction from broken bonds rebounding to original state 1,2,5,6 . Based on physical background that the electrostatic and electromechanical energy storage due to the presence of space charges could accelerate the forward transition rate of ageing and shorten the lifetime, Dissado et al proposed a quantitative model to describe insulation life under the effect of space charges 1,2 .…”

Section: Introductionmentioning

confidence: 99%

“…In the last three decades, many investigations have been made to figure out the relationship between space charge and ageing [1][2][3][4] .…”

Section: Introductionmentioning

confidence: 99%

An improved model to estimate trapping parameters in polymeric materials and its application on normal and aged low-density polyethylenes

Liu

Alghamdi

et al. 2015

Journal of Applied Physics

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Trapping parameters can be considered as one of the important attributes to describe polymeric materials. In the present paper, a more accurate charge dynamics model has been developed, which takes account of charge dynamics in both volts-on and off stage into simulation. By fitting with measured charge data with the highest R-square value, trapping parameters together with injection barrier of both normal and aged low-density polyethylene (LDPE) samples were estimated using the improved model. The results show that, after long-term ageing process, the injection barriers of both electrons and holes is lowered, overall trap depth is shallower and trap density becomes much greater. Additionally, the changes in parameters for electrons are more sensitive than those of holes after ageing.

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The role of trapped space charges in the electrical aging of insulating materials

Cited by 350 publications

References 28 publications

ac aging and space-charge characteristics in low-density polyethylene polymeric insulation

ac aging and space-charge characteristics in low-density polyethylene polymeric insulation

Short-term breakdown and long-term failure in nanodielectrics: a review

An improved model to estimate trapping parameters in polymeric materials and its application on normal and aged low-density polyethylenes

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