Performance of Thermoplastic Elastomeric and Thermoset Insulators under Accelerated Acid Rain Multistress Conditions

Polymers are becoming the material of choice for high voltage outdoor insulators. However being mostly organic, they are susceptible to aging and degradation (weathering) due to environmental (and electrical) stresses. This necessitates the study of their long-term behavior. It is desirable to study the long-term performance of the insulators in the service environment under multistress conditions encountered by the insulators to better simulate the actual conditions. This paper presents the results of the studies of a novel, third generation, environmental friendly thermoplastic elastomeric (TPE) insulators and conventional thermoset silicone rubber (SiR) insulators in Connecticut, USA and Taxila, Pakistan. 28 and 10kV insulators were used for this purpose. The aging phenomena were characterized by visual observations, hydrophobicity classification and using sophisticated materials analysis techniques, such as FTIR. The results indicated that the TPE insulators had discoloration and arcing after two thousand hours of aging while the silicone rubber insulators had no arcing.