Numerical analysis of packet-like charge behavior in low-density polyethylene under DC high electric field

Matsui, Kohei; Tanaka, Yasuhiro; Takada, Tatsuo; Maéno, Takashi

doi:10.1109/tdei.2008.4543122

Cited by 54 publications

(24 citation statements)

References 14 publications

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“…Finally, the dense positive space charges are frozen in front of the Al cathode in the steady state although the field strength in the LDPE bulk near the cathode surface is strongly enhanced. (17,18) When a constant field of over 1 MV/cm was applied to the sample as a step function, the transport of the traveling positive charge packet from the SC anode into the LDPE bulk was clearly observed as reported by Matsui et al (17,18) In the present study, however, the transport of the dense charge packet across the sample was not clearly observed. This was because the applied voltage was slowly increased step-by-step with the small step of 0.1 MV/cm.…”

Section: Effects Of Additional Antioxidant and Electrode Materialssupporting

confidence: 72%

Current Saturation Due to Strong Field Concentration into Local Thin Area in Low-density Polyethylene Sheet under Stepwise Increasing DC Voltage

2017

Sensors and Materials

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Generally, space charge formation in dielectrics subjected to DC voltage results in the enhancement of a conduction current called space-charge-limited current (SCLC). In this study, we find an interesting phenomenon that the conduction current for a low-density polyethylene (LDPE) sheet does not increase with increasing applied voltage even though a large number of space charges are accumulated in its bulk. Simultaneous measurements of the conduction current and space charge distribution are carried out for a 150-μm-thick additive-free LDPE between a semiconduction anode and an aluminum-evaporated cathode. Under a low applied field of below 0.6 MV/cm, the current is proportional to the square of the applied field because the maximum field strength in LDPE becomes higher than the mean applied field strength due to space charge formation in the LDPE bulk. Both the space charge distributions and the corresponding field distributions obtained by the simultaneous measurement roughly agree with the theoretical distributions based on the SCLC model. By increasing the applied field, however, the steady-state current saturates although a large number of positive space charges are accumulated in the LDPE bulk. We confirm that the steady-state current is restricted when a large number of frozen positive charges in front of the cathode are formed causing the strong field enhancement at a limited local thin area. These results imply that the carrier mobility at the local thin area was reduced by the excess field enhancement.

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Section: Effects Of Additional Antioxidant and Electrode Materialssupporting

confidence: 72%

Current Saturation Due to Strong Field Concentration into Local Thin Area in Low-density Polyethylene Sheet under Stepwise Increasing DC Voltage

2017

Sensors and Materials

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“…Explanations for these pulses have been proffered in terms of a negative differential resistance, 28 imbalance between injection/extraction and transport 29 or a dc-conductivity discontinuity. 30 However the current observations differ in the following important points: (a) the charge pulse always initiates from the electrode interface and contains a polarity specific quantity of carriers, and (b) the mobility of the carriers as a coherent group is many orders of magnitude higher than the carrier mobility determined from steady state currents in Polyethylene (l ¼ 10 À15 -10 À14 m 2 V À1 s À1 ). 31 …”

Section: Resultsmentioning

confidence: 88%

Fast soliton-like charge pulses in insulating polymers

Dissado

Montanari

Fabiani

2011

Journal of Applied Physics

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A previously unknown mode of conduction is identified in insulating polymers at moderate fields (40-50 MV/m). This takes the form of coherent charged pulses with a mobility ($10 À10 m 2 V À1 s À1 ) several orders of magnitude larger than that traditionally associated with independent charge carriers ($10 À14 m 2 V À1 s À1 ). It is shown that this phenomenon is consistent with a mechanism in which a charged compression boundary is formed electro-mechanically during injection and thereafter travels as a coherent solitary wave (soliton) through the polymer.

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“…13 During the past few years, several experimental and theoretical models with numerical simulation have been integrated for a better understanding of space charge dynamic and characteristics in polymer insulator under electrical stress. 14,15 Many previous works showed the existence of two charge dynamics corresponding to mobile and trapped carriers at high and low dc applied voltages, respectively. 13,[16][17][18] In this work we are interested in space charge packets that are generated under applied high dc electric field in LDPE insulating materials, which are evaluated from the experimental condition.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Space Charge Dynamic in Polyethylene Under DC Continuous Electrical Stress

Boukhari¹,

Fatiha²

2016

Journal of Elec Materi

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The space charge dynamic plays a very important role in the aging and breakdown of polymeric insulation materials under high voltage. This is due to the intensification of the local electric field and the attendant chemicalmechanical effects in the vicinity around the trapped charge. In this paper, we have investigated the space charge dynamic in low-density polyethylene under high direct-current voltage, which is evaluated by experimental conditions. The evaluation is on the basis of simulation using a bipolar charge transport model consisting of charge injection, transports, trapping, detrapping, and recombination phenomena. The theoretical formulation of the physical problem is based on the Poisson, the continuity, and the transport equations. Numerical results provide temporal and local distributions of the electric field, the space charge density for the different kinds of charges (net charge density, mobile and trapped of electron density, mobile hole density), conduction and displacement current densities, and the external current. The result shows the appearance of the negative packet-like space charge with a large amount of the bulk under the dc electric field of 100 kV/mm, and the induced distortion of the electric field is largely near to the anode, about 39% higher than the initial electric field applied.

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Numerical analysis of packet-like charge behavior in low-density polyethylene under DC high electric field

Cited by 54 publications

References 14 publications

Current Saturation Due to Strong Field Concentration into Local Thin Area in Low-density Polyethylene Sheet under Stepwise Increasing DC Voltage

Current Saturation Due to Strong Field Concentration into Local Thin Area in Low-density Polyethylene Sheet under Stepwise Increasing DC Voltage

Fast soliton-like charge pulses in insulating polymers

Simulation of Space Charge Dynamic in Polyethylene Under DC Continuous Electrical Stress

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