Effects of Climatic Aging on the Performance of EPDM Used in Power Cable Insulation

This work is intended to contribute to better understanding towards the weathering degradation of the properties of ethylene-propylene-diene-monomer (EPDM), a polymer used as insulation in medium voltage electrical cables. The samples were exposed to natural weathering in the city of Tizi-Ouzou, in northern Algeria, over a period of approximately 5.5 months. The samples were monitored using a variety of electrical and mechanical characterization methods, including measurements of bulk resistivity, dielectric strength, dielectric constant, dielectric loss factor, tensile strength, and elongation at break. Material color change, surface stiffening and increased surface cracking are the major macroscopic effects of weathering degradation. Electrical and mechanical test results show that after this period of weathering, only the resistivity and elongation at break were significantly affected. The other physical properties of the polymer were only slightly altered, suggesting the need for a longer accelerated aging period. Some of the characteristics that are measured are markers of aging that could be used in the future to predict the service life of an insulator.