Identification of electron and hole trap based on isothermal surface potential decay model

Shen, Wen-Wei; Mu, Hai-Bao; Zhang, Guanjun; Deng, Jian; Tu, Demin

doi:10.1063/1.4792491

Cited by 149 publications

(76 citation statements)

References 24 publications

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“…30 In fact, in our ISPD model, it is the injected homocharges existing in the top surface layer that 2015) determine the surface potential. Therefore, the measured trap parameters with this method mainly reveal the surface trap states of the material, 22 which is just what we most concern. Figure 7 shows the electron and hole trap energy distributions of the original and fluorinated samples.…”

Section: Electron and Hole Trap Energy Distributionmentioning

confidence: 99%

Suppression of surface charge accumulation on Al2O3-filled epoxy resin insulator under dc voltage by direct fluorination

Zhang

Wang

et al. 2015

AIP Advances

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Surface charge accumulation on insulators under high dc voltage is a major factor that may lead to the reduction of insulation levels in gas insulated devices. In this paper, disc insulators made of Al2O3-filled epoxy resin were surface fluorinated using a F2/N2 mixture (12.5% F2) at 50 °C and 0.1 MPa for different durations of 15 min, 30 min and 60 min. A dc voltage was applied to the insulator for 30 min and the charge density on its surface was measured by an electrostatic probe. The results revealed significant lower surface charge densities on the fluorinated insulators in comparison with the original one. Surface conductivity measurements indicated a higher surface conductivity by over three orders of magnitude after fluorination, which would allow the charges to transfer along the surface and thus may suppress their accumulation. Further, attenuated total reflection infrared analysis and surface morphology observations of the samples revealed that the introduction of fluoride groups altered the surface physicochemical properties. These structure changes, especially the physical defects reduced the depth of charge traps in the surface layer, which was verified by the measurement of energy distributions of the electron and hole traps based on the isothermal current theory. The results in this paper demonstrate that fluorination can be a promising and effective method to suppress surface charge accumulation on epoxy insulators in gas insulated devices.

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Section: Electron and Hole Trap Energy Distributionmentioning

confidence: 99%

Suppression of surface charge accumulation on Al2O3-filled epoxy resin insulator under dc voltage by direct fluorination

Zhang

Wang

et al. 2015

AIP Advances

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“…After that, Tu. et al applied the method to measure energy distribution of surface trap [11][12][13]. In 2011, Tang et al successfully estimated the trap energy distribution in oil-paper insulation based on the PEA results [14], which established the relationship between trap depth and charge depolarization.…”

Section: Trap Energy Distributionmentioning

confidence: 99%

Space charge behavior in thick oil-impregnated pressboard under HVDC stresses

Hao

Zhou

Wilson

et al. 2015

IEEE Trans. Dielect. Electr. Insul.

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The space charge accumulation can affect the dielectric performance of oilimpregnated pressboard in convertor transformers. In this paper, the space charge behaviour in 1mm thick impregnated pressboards is investigated by the means of pulsed electroacoustic method. The dried pressboards are separately impregnated in fresh oil and service aged oil as comparison. The space charge distributions are investigated under ±15 kV/mm and ±25 kV/mm at room temperature. The homocharge injection can be observed for all the samples, which is much more significant in the aged oil impregnated samples. The amount of injected charges and the depth of the injected charges accumulation in the pressboard bulk are closely related to the oil properties, amplitude and polarity of the applied voltages. The service aged oil shows the dominant effects on the local electric field distortion, about 48% enhanced in the aged oil impregnated samples while about 15% enhanced in the fresh oil impregnated samples. The estimations of the apparent charge mobility and trap depth also indicate the great impacts caused by the service aged oil.

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“…The surface potential decay profiles of both the original and fluorinated samples were tested by using isothermal surface potential decay (ISPD) method detailed in Ref. 11, for calculating trap characteristics of carriers. The sample is firstly charged using a corona triode and then moved to the Kelvin probe of an electrostatic voltmeter for ISPD measurement.…”

Section: Samples and Experimentsmentioning

confidence: 99%

Space charge characteristics of fluorinated polyethylene: Different effects of fluorine and oxygen

Zhao

Nie

2018

AIP Advances

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Direct fluorination are proved having obvious effect on space charge characteristics of polyethylene. It is believed that fluorine has a positive effect on suppressing space charge injection while oxygen impurity has a negative effect. However, the mechanism for the opposite effect of fluorine and oxygen is still not clear. In this paper, the different effects of fluorine and oxygen on space charge characteristics of fluorinated low density polyethylene (LDPE) are investigated on the basis of dielectric property, chemical constitutes and trap performance of surface fluorinated layers. The results show that direct fluorination has obvious effect on chemical constitutes and dielectric properties of surface fluorinated layer. Introduced fluorine is the main factor for suppressing charge injection from the electrodes, because it seriously changes the chemical constitutes and further the trap properties of the surface fluorinated layer. While introduction of oxygen results in heterocharges and makes space charge distribution complex, due to the ionization of generated small groups like C=O containing groups. Moreover, direct fluorination will result in cleavage of some LDPE molecules whatever there is oxygen impurity or not.

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Identification of electron and hole trap based on isothermal surface potential decay model

Cited by 149 publications

References 24 publications

Suppression of surface charge accumulation on Al2O3-filled epoxy resin insulator under dc voltage by direct fluorination

Suppression of surface charge accumulation on Al2O3-filled epoxy resin insulator under dc voltage by direct fluorination

Space charge behavior in thick oil-impregnated pressboard under HVDC stresses

Space charge characteristics of fluorinated polyethylene: Different effects of fluorine and oxygen

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