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Title: "Sub-hertz" dielectric spectroscopy
Authors: Fothergill, John C.
See, K.B.A
Ajour, M.N.
Dissado, Len A.
First Published: 2005
Presented at: International Symposium on Electrical Insulating Materials, Kitakyushu, Japan
Start Date: 5-Jun-2005
End Date: 9-Jun-2005
Publisher: IEEE
Citation: Proceedings of the 2005 International Symposium on Electrical Insulating Materials, 2005, 1-3, pp. 821-824
Abstract: Dielectric spectroscopy measurements below 1 Hz are often dominated by "conduction-like" effects. For this reason, they often appear to be dismissed as being of little interest. In this paper two "sub-hertz" responses are considered that give insights into the insulating systems concerned. The first system is that of cross-linked polyethylene, taken from a power cable system. Measurements at temperatures between 60 C and close to melting at 100 C show a change in characteristic from a percolation process to a "true" DC conduction at close to the melting point. Using DC conductivities, it appears to be possible to show whether the cable has been subjected to thermo-electric ageing. This might give insights into where the conduction and hence the ageing in the XLPE is occurring. The second system is an epoxy composite. By considering the sub-hertz response, it is possible to demonstrate the effect of the interface between the filler and the epoxy matrix. In this system, ageing, resulting in delamination between the glass fiber filler and the epoxy, is clearly detected by sub-hertz dielectric spectroscopy. This process is likely to be facilitated by the presence of water, which is known to lead to mechanical failure in such systems, and which can also be detected by "sub-hertz" dielectric spectroscopy. The implications for nano-dielectrics are then briefly considered.
DOI Link: 10.1109/ISEIM.2005.193505
ISBN: 4-88686-063-X
Version: Post-print
Status: Peer-reviewed
Type: Conference Paper
Rights: Copyright © 2005 IEEE.
Appears in Collections:Conference Papers & Presentations, Dept. of Engineering

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