Abstract:
Water and heat are the most degrading factors for the outdoor insulators. Whenever the
insulators are placed in an outdoor field, they are subjected to severe mechanical
compression which affects the dielectric properties. The RTV-SiR and its composites are
discussed in this study under high temperature and humidity and mechanical compression
effects. There were five different sample compositions. There were two micro composites
(15 wt% silica) and (15 wt% ATH). A nano-composite (2.5wt% SiO2) and a hybrid
composite (10wt% micro ATH with 2wt% nano-silica). After preparing the samples they
were subjected to mechanical compression of 0 MPa to 12 MPa with a step of 3 MPa. LCR meter was used to measure the effect of mechanical compression on dielectric properties.
Hydrothermal aging setup was used. The temperature was set to 70° C and 80% humidity.
Hydrophobicity, structural and chemical analysis as well surface degradation was used to
analyze the chemical and physical properties of silicone rubber after hydrothermal-stress
is applied. The analyses confirmed the excellent recovery characteristics of silicone rubber
towards the applied conditions. SMC 15% ATH outperformed the other samples by
showing most resistance and recovery. Hybrid composite showed excellent hydrophobic
behavior among other composites. It showed the highest contact angle of 138˚ after 120
hours. High temperature caused rapid recovery of hydrophobicity for all samples. The
surface topography of SMC 15% ATH sample showed no cracks and lesser pathways as
compared to other samples. In Fourier Transform Infrared (FTIR) Spectroscopy ATH
based microcomposites has shown values of 123, 116%, 110, 116%, and 120% in
prominent functional groups peaks. Microcomposite with 15% ATH samples outperformed
the other samples. ATH filler based composite is used in high temperature and humidity
environment. Similarly for mechanical compression it has the ability to bear the most
mechanical stress with least change in the dielectric properties. For high voltage insulation
purpose the silicone-based composites should be designed with ATH filler.
