Investigating ac space charge accumulation in polymers by PEA measurements

Montanari, G.C.; Mazzanti, G.; Boni, Evangelista; Robertis, G. De

doi:10.1109/ceidp.2000.885240

Cited by 15 publications

(14 citation statements)

References 12 publications

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“…However, increasing temperature undoubtedly breaks the rule with negative charge accumulation clearly observable at 10Hz and 50°C. Measurements up to 50Hz are achievable with the actual PEA hardware with careful prevention of surface and corona discharges in the environment of samples [6,9]. As measurements can be achieved safely up to 6kV voltage only at 50Hz [9], they were not attempted in the present set.…”

Section: Discussionmentioning

confidence: 99%

Space-charge dynamic in polyethylene: from dc to ac stress

Thomas

Teyssèdre

Laurent

2010

J. Phys. D: Appl. Phys.

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Abstract. Time-resolved space charge profiles obtained in low density polyethylene under sinusoidal or square AC stress for frequencies going from DC to 10 Hz, temperature from 25 to 50°C and fields of 30 or 40 kV/mm are presented. It is shown that most of the features observed under DC stress (generation of carriers of the two polarities with non-symmetrical amount and velocity) are still active under AC stress. As a matter of fact, it is shown that a negative space charge builds up at 50°C within the whole insulation bulk even with relatively high stress frequency and for short stressing time (2 h). These results clearly show that space charge has to be considered under AC condition.Confidential: not for distribution.

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Section: Discussionmentioning

confidence: 99%

Space-charge dynamic in polyethylene: from dc to ac stress

Thomas

Teyssèdre

Laurent

2010

J. Phys. D: Appl. Phys.

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“…In order to measure space charge under acfields by the pulsed electroacoustic technique [106,107], synchronization with zero voltage is needed to eliminate the effect of the electrode charges due to the ac source (although a new method has been developed to avoid this [108]), see [109]. This permits space charge profiles to be obtained at 0° (or 360°) and 180°, achieving the maximum sensitivity of the PEA system.…”

Section: Space Charge Accumulation As a Function Of Supply Voltage Frmentioning

confidence: 99%

Bringing an insulation to failure: the role of space charge

Montanari

2011

IEEE Trans. Dielect. Electr. Insul.

267

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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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“…Space charge characteristics of insulating materials under AC voltage and DC voltage are equally important [6][7][8][9]. However, the space charge characteristics of insulating materials under AC condition have not been widely carried out due to the complexity of the testing and the hardware restriction.…”

Section: Introductionmentioning

confidence: 99%

Space charge characteristics of oil impregnated insulation paper under the power frequency voltage

Hao¹,

Wu²,

Fu³

et al. 2013

2013 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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Space charge characteristics of insulating materials under AC voltage and DC voltage are equally important. There is a huge amount of AC transformers in the power transmission system. However, there is no report about the space charge characteristics of the oil-paper insulation materials under the AC voltage. In this paper, firstly, the space charge characteristics of the oil immersed insulating paper under the positive/negative DC field were investigated using the pulsed electro-acoustic (PEA) method. Secondly, the space charge characteristics of the oil immersed insulating paper under power frequency voltage were studied using the improved PEA system. Results show that the electric field polarity has a decisive impact on the charge distribution. When the DC electrical field is positive polarity, the polarity of the charge accumulated at the paper-paper interface near the aluminum electrode is positive, while it is negative when the DC field strength is negative. The charge polarity of the charge accumulated at the aluminum electrode is negative in the positive half cycle under the power frequency voltage. It is positive in the negative half cycle of the power frequency voltage. The charge polarity of the charges accumulated at the internal interface of the oil-immersed insulation paper are opposite for 90° and 270° phase in the voltage applied process. The charges accumulated within the oil-immersed insulating paper under the power frequency voltage show a significant reduction compared with the results under DC voltage.

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Investigating ac space charge accumulation in polymers by PEA measurements

Cited by 15 publications

References 12 publications

Space-charge dynamic in polyethylene: from dc to ac stress

Space-charge dynamic in polyethylene: from dc to ac stress

Bringing an insulation to failure: the role of space charge

Space charge characteristics of oil impregnated insulation paper under the power frequency voltage

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