Multistress accelerated aging of polymer housed surge arresters under simulated coastal Florida conditions

Long-term performance of polymer housed surge arresters under multistress accelerated conditions simulating coastal Florida service environment in the lab has been presented. Commercial 9 kV ethylene propylene silicone blend (EPSB) and silicone rubber (SiR) arresters were procured and used for this purpose. Multi-stress aging was used to realistically and meaningfully simulate the actual service environment that has the synergy of several environmental stresses. The various stresses applied include ultraviolet-A radiation (UVA), rain, heat, clear mist, and salt fog. Summer and winter weather cycles were designed to apply these stresses cyclically as they occur in the service environment. This method provides a comprehensive evaluation of the insulator, the hardware and its attachment. Coastal Florida conditions were chosen as the year-around warm temperatures and the high humidity challenge any insulating material, ceramic or polymeric. The evaluation was conducted for a period of 15 simulated service years of aging (15 lab-years) in the multistress accelerated aging chamber. Compared to the unaged (virgin) sample, the EPSB arresters showed chalking, reduced hydrophobicity, and reduction in hydrocarbon (CH) group molecules in the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) measurements. The SiR arrester surfaces showed no noticeable changes in the FTIR measurements. However, scanning electron microscopy (SEM) micrographs indicated increased surface roughness and disintegration of the material for both the SiR and EPSB surfaces. Research results indicated that multistress accelerated tests are desirable since they reflect the real world.