Characterizing HV XLPE cables by electrical, chemical and microstructural measurements on cable peeling: Effects of surface roughness, thermal treatment and peeling location

Characterization of the electrical, chemical, and microstructural properties of high voltage cables was the first step of the European project “ARTEMIS”, which has the aim of investigating degradation processes and constructing aging models for the diagnosis of cross-linked polyethylene (XLPE) cables. Cables produced by two different manufacturers were subjected to a large number of electrical, microstructural, and chemical characterizations, using cable peelings, instead of lengths of whole cables, as specimens for the measurements. Here the effect of surface deformation and roughness due to peeling and the relevance and significance of thermal pre-treatment prior to electrical and other measurements is discussed. Special emphasis is put on space charge, conduction current and luminescence measurements. We also consider the dependence of these properties on the spatial position of the specimen within the cable. It is shown that even though the two faces of the cable peel specimens have different roughness, the low-field electrical properties seem quite insensitive to surface roughness, while significant differences are detectable at high fields. Thermal pre-treatment is required to stabilize the insulating material to enable us to obtain reproducible results and reliable inter-comparisons throughout the whole project. The spatial position of the specimens along the cable radius can also have a non-negligible influence on the measured properties, due to differential microstructure and chemical composition

Water trees in medium voltage XLPE cables: comparison of different polyethylene insulation using short time accelerated ageing tests

This paper describes a pragmatic method to assess the resistance of medium voltage polymeric cable insulation to water treeing. Water trees (WT) with a length between 100 and 800 μm are produced in 12 days in the polyethylene insulation of commercial cable samples by use of a high frequency, high voltage power supply. The initial objective was to provide a source of information for asset management eg estimating the remaining life of installed cables. However, the very short time necessary to generate water trees with this method will allow its use for the assessment of new products and provides a rapid comparison technique between different materials. The obtained results show that WTs grow in all kinds of cables but depending on the insulation type, the shape and speed of growth are different

Electrical and Physico-chemical Analysis of Belgium Medium Voltage Cables Data Bank

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Efficiency of shot peening to prevent PWSCC of steam generator tubes removed form DOEL 3

Translated from FrenchAvailable from British Library Document Supply Centre- DSC:9091.9(Risley-Trans--6061)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo