Multistress Accelerated Aging and Tracking/Erosion-Resistance Investigation of High Voltage Polymeric Insulators

All over the world, room temperature-vulcanized silicone rubber has been widely used for outdoor electrical and non-electrical applications. However, in outdoor applications, the electrical and non-electrical properties of weather-sheds/sheaths of polymeric insulators were gradually degraded over time, which has become an unavoidable issue. In this work, we have presented the 5000-h multistress accelerated laboratory-aging and tracking/erosion-resistance analysis of alumina-tri-hydrate/silica-filled SiR composites, simulating actual field environment of Islamabad (Pakistan). In addition, to quantify the blends surface resistance to tracking and erosion, the inclined plane test was conducted according to ASTM-D2303 standard. To evaluate distinct properties, various stresses such as heat, ultraviolet radiation, salt fog, acid rain and humidity were sequentially applied over weathering period in a multistress accelerated aging chamber. Summer and winter weathering cycles were so designed as they occurred in the actual environment. Moreover, to investigate the physical and chemical changes as a function of time (0–5000 h), critical visual inspection, leakage current statistics, hydrophobicity, Fourier transform infrared (FTIR) spectroscopy and tracking/erosion analysis tests were conducted as planned. Compared to neat SiR sample, slight discoloration/roughness was exhibited by all other specimens. The hydrophobicity, leakage current and tracking/erosion results of SiR composites showed a strong correlation between surface condition and performance with respect to leakage current and applied voltage over the weathering period. Moreover, the FTIR results of all blends showed a considerable hydrocarbon (C–H) loss of chemical groups compared to virgin samples. Hence, it is suggested that multistress accelerated aging along with tracking/erosion analysis tests can be adopted to quantify and analyze the insulators behavior in real world.