Study on space charge dynamics by computer simulation: Formation and transport of space charge packet

Kaneko, K.; Odaka, Takahiro; Suzuoki, Y.; Mizutani, Tadashi

doi:10.1109/icpadm.1997.616563

Cited by 4 publications

(4 citation statements)

References 4 publications

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“…They are activated generally by high DC fields, with inception values depending on material (lowered by the presence of contaminants), temperature and mechanical stress [10][11][12][13][14]. They have typically mobility in the range 10 -14 to 10 -12 m 2 V -1 s -1 , and for this reason they are named in the following as -slow‖ packets.…”

Section: Introductionmentioning

confidence: 99%

Fast and slow charge packets in polymeric materials under DC stress

Fabiani

Montanari

Dissado

et al. 2009

IEEE Trans. Dielect. Electr. Insul.

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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 been observed, in fact, that such packets can cause accelerated breakdown of insulation.The development of fast systems for space charge measurements has allowed the presence of almost instant heterocharge to be observed close to electrodes in certain field and temperature conditions, especially in cable models. This has been explained often by the separation of ionic charge populations, even though such heterocharge appears also in materials, such as Polyethylene or cross-linked Polyethylene that represent the best extra-clean technologies. The measurements reported here use a high speed technique to investigate the build up of heterocharge in model cables that have been treated to remove volatile chemical species. They show that in fact the heterocharge is built up by many very small and very fast charge packets (i.e. charge packets having a high mobility), which are injected from both electrodes and cross the insulation in less than one second. Because the packet charge is unable to exit the counter-electrode at the same rate at which it arrives, hetero-charge is built up within just a few seconds from the beginning of the polarization. The mobility of these charges, depending significantly on temperature, is estimated through observation of charge packets as a function of time, and compared with that of the already-known slow packets, generally occurring at higher fields with respect to fast packets. The basis for the interpretation and modelling of such phenomena is discussed.

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Section: Introductionmentioning

confidence: 99%

Fast and slow charge packets in polymeric materials under DC stress

Fabiani

Montanari

Dissado

et al. 2009

IEEE Trans. Dielect. Electr. Insul.

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“…They are activated generally by high dc fields, with inception values depending on material (lowered by the presence of contaminants), temperature and mechanical stress [81][82][83][84][85]. They have typically a mobility in the range 10 -14 to 10 -12 m 2 V -1 s -1 , and for this reason they are considered in [86] as "slow" packets in contrast to the "fast" packet dealt with in the next sub-section.…”

Section: Voltagementioning

confidence: 99%

Bringing an insulation to failure: the role of space charge

Montanari

2011

IEEE Trans. Dielect. Electr. Insul.

274

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Considering the title of this paper, one might think that everything has been said, shown, proven and discussed already on ageing and failure of electrical insulating materials, based on at least half century of research work and field feedbacks. However, perhaps there is still room to collect ideas and speculate on apparently proven or brand new concepts, such as the interrelation between ageing mechanisms and physically measurable quantities such as space charge, partial discharges and conduction current. The latter is, indeed, the scope of this paper, which is taken from the Whitehead Memorial Lecture given at the 2010 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP). On one hand we will revisit the concepts of space charge accumulation in insulating (polymeric) materials, considering also the latest achievements which deal with ultra-fast charge pulses (solitons), on the other hand we will discuss how space charge can contribute to ageing rate under dc, ac or impulsive voltage, directly through electric field alteration, or indirectly modifying a fundamental ageing factor such as partial discharges.The goal is, at the very end, to show how much such basic investigations can have a fundamental impact on insulation design and electrical apparatus long-term performance/ reliability. Index Terms -Space charge,degradation, charge packets,aging models, partial discharges, insulation breakdown. 2 2 4 ,where J ii is the impact ionization rate, I is the ionization energy, J DEA is the Dissociative Electron Attachment Gian Carlo Montanari (M'87-SM'90-F'00) was born on 8 November 1955. In 1979, he took the Master degree in electrical engineering at the University of Bologna. He is currently Full Professor of Electrical Technology at the Department of Electrical Engineering of the University of Bologna, and teaches courses of Technology and Reliability. He has worked since 1979 in the field of aging and endurance of solid insulating materials and systems, of diagnostics of electrical systems and innovative electrical materials (magnetics, nanomaterials, electrets, superconductors). He has been also engaged in the fields of power quality and energy market, power electronics, reliability and statistics of electrical systems. He is a member of AEI and Institute of Physics. He is a member of the AdCom of the IEEE DEIS. Since

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“…Over recent decades, a great deal of effort has been expended in developing experimental tools for space charge characterization [184,186] in measuring space charge profiles [169,181] or in identifying the different kinds of charges [73,187]. Meanwhile, only a few attempts have been made to provide some model description of these experimental results [188][189][190][191][192].…”

Section: Space Charge-limited Field (Sclf)mentioning

confidence: 99%

“…This approach, which has already been described in several papers [128,188], is depicted in Figure 4-29. Trapping phenomena responsible for long lasting space charge are described by a unique deep trapping level [188,190]. For mobile (or trapped) electrons and holes, the continuity equation is solved as the following set of partial differential equations [128,189]: The de-trapping probability is defined by a de-trapping coefficient, for each species, which is of the form:…”

Section: Unique Deep Trapping Level ("Model I")mentioning

confidence: 99%

Study on electrical characteristics of XLPE insulation of high voltage cable

Yang¹

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Study on space charge dynamics by computer simulation: Formation and transport of space charge packet

Cited by 4 publications

References 4 publications

Fast and slow charge packets in polymeric materials under DC stress

Fast and slow charge packets in polymeric materials under DC stress

Bringing an insulation to failure: the role of space charge

Study on electrical characteristics of XLPE insulation of high voltage cable

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