Comparison Between Crosslincable Silane-XLPE and Peroxide-XLPE HV Insulation under Cyclic Accelerated Weathering Aging – FTIR Study

The talented properties of crosslinked polyethylene (XLPE) places him in the first position as insulation in the manufacturing of underground transmission and distribution cables. It can also be used as insulation of cables in photovoltaic systems because its resistance to the weathering conditions. It is well known that over the operating period, cables are subjected permanently to the environmental conditions leading to the weathering aging. In this kind of aging the effects of ultraviolet radiation (UV) of sunlight, temperature and humidity are conjointly superposed leading to modify morphology (physical aspect) and composition (chemical aspect) of the material under photo and thermo-degradation process. Chemical modifications in the XLPE structure under accelerated cyclic weathering aging are highlighted by the use of Infrared Spectroscopy (FTIR). The studied materials were cross-linkable silane-XLPE and peroxide-XLPE. From the obtained results, it can be stated that accelerated weathering aging leads, on one hand, to a pronounced changes in the digital fingerprint of both materials by the occurrence of crosslinking reactions. On the other hand, some chemical changes like photo and thermo-oxidative degradation quantified by the increase of carbonyl index. The overall conclusion suggests that silane-XLPE presents best stability under environmental conditions and has a less susceptibility to degradation than peroxide-XLPE.