Showing papers by "John C. Fothergill published in 2003"
TL;DR: This stage of the ARTEMIS programme is now complete and an analysis of the results will show how they may be correlated with the concepts proposed in aging theories.
Abstract: The aim of the European project "ARTEMIS" is to develop a diagnostic system for assessing aging in power cable insulation. Its first task was to make a thorough characterisation of the cable insulation before aging. This is intended to provide a background against which any changes introduced by thermo-electric aging can be identified. The aging markers derived from this initial characterisation will be considered both as diagnostic indicators in their own right, and also to develop an aging model for predictive purposes, if and when possible. This stage of the ARTEMIS programme is now complete and we will present an analysis of the results, and show how they may be correlated with the concepts proposed in aging theories.
110 citations
TL;DR: In this paper, a technique for making dielectric spectroscopy measurements of very small quantities of silicone oil was described, where surface tension was used to hold the oil between the plates of a capacitor, the inter-electrode distance being controlled by a micrometer.
Abstract: A technique is described for making dielectric spectroscopy measurements of very small quantities (<1 /spl mu/l) of oil. The technique utilises surface tension to hold the oil between the plates of a capacitor, the inter-electrode distance being controlled by a micrometer. Breakdown strength can also be estimated using this technique. Three samples of silicone oil, used in cable sealing ends, were tested: virgin, used and failed. A major component in the frequency dependent impedance had the form Z(/spl omega/) = B(1-b(i/spl omega/)/sup 1-p/). This component was interpreted in terms of a fractal percolation model, and the anomalous thickness dependence predicted by the model verified by varying the inter-electrode distance. The difference observed for the three different samples indicate that conducting contaminants are responsible for the percolation system.
9 citations