Natural and Artificial Weathering of EPDM Compounds Used in Outdoor High Voltage Insulation

Results are presented on the weathering behavior of EPDM compounds suitable as a protective housing material for HV plastic insulators. Two accelerated tests have been used: thermal aging under pressurized O2, and Xenon lamp irradiation. Structural changes are followed through swelling and ATR infra-red speotroscopy measurements. The efficiency of various UV absorbers is compared with respect to surface and bulk protection. The resistance to erosion and tracking of one particular protected compound is followed as a function of natural weathering exposure; it is found that in spite of apparent surfaceodifi modifications, this electrical property is not altered after several years of outdoor exposure.