This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: G. Teyssedre and C. Laurent: Semi-quantitative Analysis of Photoluminescence in Thermoelectrically Aged Cables : I 1070-9878/09/$25.00 © 2009 IEEE 1180 Semi-quantitative Analysis of Photoluminescence in Thermoelectrically Aged Cables: I-Identification of Optical Signatures G. Teyssedre 1,2 and C. Laurent 1,2 1 Université de Toulouse ; UPS, INPT ; LAPLACE (Laboratoire Plasma et Conversion d’Energie) 118 route de Narbonne, F-31062 Toulouse cedex 9, France 2 CNRS ; LAPLACE ; F-31062 Toulouse, France ABSTRACT Photoluminescence measurements have been carried out along the radius of the insulation of un-aged and thermo-electrically aged HVAC cables. A specific emission, with maximum at 400 nm has been isolated in the emission spectrum of cross-linked polyethylene insulation in the vicinity of the semi-conducting screens. Complementary measurements on lab-compounded samples were carried in order to unravel the nature of the emitting species. It is shown that the antioxidant –or its derivatives- used for the semi-conducting screens are at the origin of this emission and exhibit significant diffusion within the bulk of the insulation. The evolution of the shape of the photoluminescence spectra with thermal ageing is presented and a procedure for decomposing emission spectra into the contributing elementary processes is proposed. Index Terms — Cross-linked polyethylene, XLPE, high-voltage cable, diffusion, semi-conducting screen, antioxidant. 1 INTRODUCTION THE ageing mechanisms of cross-linked polyethylene-XLPE- insulated high voltage cables submitted to thermoelectric stress have been investigated for many years. Two technical aspects are associated with these researches. On the one hand, there is the need for observables of the insulation ageing level, and this is associated with maintenance of existing buried lines. The other aspect concerns the need of knowledge for the limiting factors in the performance of the insulating material: from there strategies for improving the formulation of XLPE can be devised along with an optimization of design stresses. For both perspectives, the parameters relevant of an evolution of the insulating material, and more precisely of a loss of the electrical performance of the insulation, have to be identified. Indeed, any evolution of physical or chemical properties of the material is not necessarily detrimental to the insulation. The work described here was carried out in part in the frame of the European ARTEMIS project (1999-2003) . The ARTEMIS partners included cable manufacturers, material suppliers, electricity distributors, and a number of universities throughout Europe. The project aimed at setting up diagnostic methodologies for evaluating the degree of ageing and the reliability of in-service power cables and improved design and manufacturing techniques. In the project, a variety of investigative techniques have been applied to samples peeled from full-sized XLPE-insulated cables. The use of peelings as from full-sized XLPE-insulated cables....
View Full Document
- Spring '11
- power cable, NM, High voltage cable, Cross-linked polyethylene, Thermoelectrically Aged Cables