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|Title:||Charge Transport in Thermally Aged Paper Impregnated with Natural Ester Oil|
|Authors:||Abdelmalik, A. A.|
Dodd, Stephen John
Dissado, L. A.
Chalashkanov, N. M.
Fothergill, J. C.
|Publisher:||Institute of Electrical and Electronics Engineers (IEEE), United States|
|Citation:||IEEE Transactions On Dielectrics And Electrical Insulation, 2014, 21 (5), pp. 2318-2328 (11)|
|Abstract:||Samples of a dried composite oil-paper system were thermally aged in the laboratory under N2 in a sealed container and analysed using their dielectric response. The contributing loss processes were separated using an equivalent circuit model containing constant high frequency capacitances, dc-conductances, a dispersive capacitance, and a low frequency quasi-dc (q-dc) dispersion process as circuit elements. This low frequency dispersion in oil-paper samples is a bulk property of the system that is often mistaken for a dc conduction process when only the imaginary capacitance or ac-conductance is measured. The Dissado-Hill response function is proposed for the frequency dependence of the dispersive capacitance in the mid-frequency range rather than the Debye function because its cluster concepts correlate with the sample morphology of a matrix of oil-filled cavities. The quasi-dc dispersion is assigned to the transport of mobile charges between charge-clusters associated with locally connected oil filled cavities, which is a process that can be represented on a global scale by the form of hierarchical circuit system that leads to constant phase angle responses, and is here modelled by the Dissado-Hill q-dc function. It was found that the two dispersions moved together to higher frequency with thermal ageing of the composite material. The characteristic frequency common to the dispersions had an activation energy that decreased with thermal ageing, whereas their amplitude increased. This behavior is discussed in terms of possible changes to the oil-paper composite caused by the ageing process.|
|Rights:||Copyright © 2014, IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.|
|Appears in Collections:||Published Articles, Dept. of Engineering|
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|Carge Transport paper_TDEI_after_review_final SUBMITTED VERSION_01_04_2014.pdf||Post-review (final submitted)||412.83 kB||Adobe PDF||View/Open|
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