Oxidation and Water Tree Formation in Service-Aged XLPE Cable Insulation
- 1 August 1987
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Electrical Insulation
- Vol. EI-22 (4), 405-412
- https://doi.org/10.1109/tei.1987.298900
Abstract
The insulation from six 5 kV power cables, which has been in service underground for 6 to 8 years, was examined by infrared (IR) spectroscopy and oxidation induction time (OIT) analysis. Sections of insulation containing water trees were found to contain high levels of ionic contaminants. All insulation samples showed evidence of oxidative degradation in service and frequently there was a higher than average level of oxidation in the treed regions of the insulation. Sections of the insulation containing water trees had appreciably shorter OIT's than untreed regions, indicating that they were more prone to subsequent oxidative degradation. A model for water tree formation and electrical breakdown of the insulation is described where oxidative degradation during prolonged service reduces the ability of the insulation to withstand stress concentrations at defects, and water trees are initiated. Some localized oxidation may accompany the tree propagation step. Extensive localized oxidation then takes place in the treed regions, catalyzed by ionic contaminants, and insulation failure occurs.Keywords
This publication has 6 references indexed in Scilit:
- Water Treeing in Solid DielectricsIEEE Transactions on Electrical Insulation, 1984
- An Accelerated Life Test for Evaluating Power Cable InsulationIEEE Transactions on Power Apparatus and Systems, 1981
- Initial Results of a Study of Water Trees in XLPE by Infrared SpectroscopyIEEE Transactions on Electrical Insulation, 1980
- Mechanism of oxidation at a copper–polyethylene interface. II. Penetration of copper ions in the polyethylene matrixJournal of Polymer Science: Polymer Chemistry Edition, 1976
- INFRARED SPECTRA OF INORGANIC COMPOUNDSPublished by Elsevier ,1971
- Analysis of the nonvolatile oxidation products of polypropylene I. Thermal oxidationJournal of Polymer Science Part A-1: Polymer Chemistry, 1970