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The developed DC space-charge life model has been used to investigate the effect of trap cross-sections and trapped charges on the aging process in polymers. The experiment was performed using a two-dimensional grid that consists of multiple squares with micro dimensions that are treated as isolated regions. This grid was used to represent the evolution of damage structures during the aging process...
Large number of studies describes phenomena associated with space charge build-up in polymeric materials and the incited consequences when high voltage direct current is imposed. Currently, the studies are oriented towards possibilities to minimize this drawback by addition of nanometric size inclusions into the bulk of the polymer material. One alternative approach is to tailor the interface of the...
Charge packet under high electric dc fields has been observed in polyethylene and its formation has been closely associated with ageing and breakdown of the insulating material. To understand the mechanisms several models have been proposed. In this paper, two models originated from completely different approaches have been reviewed. The first model proposed is based on bipolar charge injection together...
Trap depth in polyethylene was numerically estimated using calculation of molecular orbital method. In polymeric material, electric conduction seems to be strongly affected by the existence of carrier traps. Therefore the estimation of trap depth is one of important factors for electrical characterization of polymeric materials. However, there are not so many examples to estimate the trap depth. Therefore,...
Small but repetitive charge packets injected from both electrodes, that cross insulation very rapidly and accumulate at the counter electrodes, are observed in polyethylene-based insulating materials. The results presented in this paper show that the charge packet amplitude remains almost independent of field and temperature, while mobility and repetition rate are thermally activated quantities. This...
The presence of slow space charge packets crossing the insulation thickness from one electrode to the other and causing significant electrical field distortion has been reported already in several papers. They are activated in general by very high dc fields or, in highly polluted materials, by relatively low fields and constitute an important ageing factor, concerning dc electrical stress. It has...
Whenever a polymeric material is subjected to an electrical stress, imperfections such as protrusions, contaminants and microvoids, will all act as points where the field is enhanced, causing the degradation processes to be initiated. However, as manufacturing technology improves, insulation systems are of higher quality and their interfaces smoother. The reduction in concentration and size of impurities...
Charge accumulation characteristics in dielectric materials for a spacecraft were studied to elucidate spacecraft charging problems in a high-energy radiation environment. This study especially addressed spacecraft charging accidents caused by internal charge accumulation in dielectric materials irradiated by electron and proton beams. Internal charge measurements of those bulk materials were carried...
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