Effect of AC ageing on space charge evolution in XLPE

Chong, Y.L.; Chen, G.; Miyake, Hiroaki; Tanaka, Yasuhiro; Takada, Tatsuo

doi:10.1109/ceidp.2004.1364194

Cited by 2 publications

(4 citation statements)

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“…It has been reported that space charge trapped in samples of LDPE or indeed XLPE tends to decay at a slower rate when the samples have been aged under dc [26][27][28] or ac [29][30][31][32] electric stress for longer duration or higher stress level as compared to one aged for a shorter duration or lower stress level when short-circuited. Bearing this in mind, the reduction of fast charge in sample A could be interpreted as indicating formation of deep traps being accompanied by reduction of shallow ones as a result of dc ageing.…”

Section: As-received Samplesmentioning

confidence: 99%

Temperature effect on space charge dynamics in XLPE insulation

Chong

Chen

2007

IEEE Trans. Dielect. Electr. Insul.

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This paper reports on space charge evolution in crosslinked polyethylene (XLPE) planar samples approximately 1.20 mm thick subjected to electric stress level of 30 kV dc /mm at four temperatures 25, 50, 70 and 90 o C for 24 h. Space charge profiles in both asreceived and degassed samples were measured using the laser induced pressure pulse (LIPP) technique. The dc threshold stresses at which space charge initiates are greatly affected by testing temperatures. The results suggest that testing temperature has numerous effects on space charge dynamics such as enhancement of ionic dissociation of polar crosslinked by-products, charge injection, charge mobility and electrical conductivity. Space charge distributions of very different nature were seen at lower temperatures when comparing the results of as-received samples with degassed samples. However at higher temperature, the space charge distribution took the same form, although of lower concentration in degassed samples. Space charge distributions are dominated by positive charge when tested at high temperatures regardless of sample treatment and positive charge propagation enhances as testing temperature increases. This can be a major cause of concern as positive charge propagation has been reported to be related to insulation breakdown.

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Section: As-received Samplesmentioning

confidence: 99%

Temperature effect on space charge dynamics in XLPE insulation

Chong

Chen

2007

IEEE Trans. Dielect. Electr. Insul.

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“…acetophenone generated by the cross-linking reactions, and the partial alignment of these molecules, generating polarization in the sample bulk, would have persisted for some time after the end of poling. Thus measurements made immediately after the end of poling would probably reflect electric field and polarization distributions, as given by equation (2). However, in the absence of reliable quantitative polarization data, P(z) in equation (2) was set to zero.…”

Section: Resultsmentioning

confidence: 99%

“…The corresponding PEB profile is given by the dotted points. In the calculations, α z in equation (2) was taken as 2 x 10 -4 / o C [14] and α ε as -2.43 α z , the latter following from differentiation of the Clausius-Mossotti relation with respect to temperature [15] and ε = 2.3. The accuracy of the experimental data falls off rapidly with increasing distance from the laser-irradiated surface, due to the attenuation of the heat pulse in transit.…”

Section: Resultsmentioning

confidence: 99%

“…Most of this space charge accumulates near the interface of the insulation with the inner semicon layer, where the electric field is largest. Much experimental work has been done on the problem, mostly involving the laser-induced-pressure-pulse (LIPP) or pulsed-electroacoustic (PEA) techniques to measure the space charge profiles in samples 1-2 mm thick [1][2][3]. Although a spatial resolution (in the thickness direction) of about 4 μm in samples 25 and 75 μm thick was claimed in one of the earliest LIPP measurements [4], the resolution achievable using the LIPP or PEA technique and equipment with average specifications is unlikely to be better than about 20 μm [5].…”

Section: Introductionmentioning

confidence: 99%

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LIMM study of space charge in crosslinked polyethylene

Pawłowski

Fleming

Lang

2006

IEEE Trans. Dielect. Electr. Insul.

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Electric field / space charge profiles obtained using the laser-intensity-modulationmethod (LIMM) are presented for XLPE samples machined from power cable insulation cross-linked using dicumyl peroxide. The samples, 110 μm thick with vacuum-evaporated aluminium electrodes, were subjected to dc fields of 48 kV/mm and both polarities at room temperature for at least 24 hr. The LIMM measurements were made at room temperature, and at various times after the end of poling. Electric field and space charge profiles obtained using the scaletransformation and polynomial regularization methods were in fair quantitative agreement over much of the sample thickness, except when the electric field showed a maximum or minimum. Simulation data for assumed electric field profiles strongly suggested that the polynomial regularization method is more accurate. Most of the space charge was concentrated near the electrodes, with densities of order 5-10 C m -3 in those regions. Charge of the same sign tended to accumulate adjacent to a given physical electrode, for both poling polarities.

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Effect of AC ageing on space charge evolution in XLPE

Cited by 2 publications

References 6 publications

Temperature effect on space charge dynamics in XLPE insulation

Temperature effect on space charge dynamics in XLPE insulation

LIMM study of space charge in crosslinked polyethylene

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