Abstract:
Silicone rubber (SiR) has seen a substantial increase in application for high
voltage electrical insulation in outdoor conditions during the last three
decades due to its exceptional properties, particularly its high hydrophobicity.
However, because it is organic in nature, it deteriorates when subjected to
multiple stresses, resulting in the loss of desired attributes that have a direct
impact on their long-life. The loss in the characteristics prevent it from being
widely accepted in the power system insulation as replacement of
conventional ceramic insulators. Moreover, Inorganic fillers improve the
dielectric and high voltage insulation properties, expanding potential
applications of silicone rubber in many electrical appliances. The objective of
this research is to investigate the electrical properties of multi stressed aged
high-temperature vulcanized (HTV) silicone rubber (SiR) hybrid composites
containing silica and Aluminium trihydrate (ATH) fillers. Five hybrid
composites comprising of 20% micro-ATH with 2% nano silica (SAT-2), 4%
nano silica (SAT-4), 6% nano silica (SAT-6), 8% nano silica (SAT-8), 10%
nano silica (SAT-10) along with neat HTV SiR (SAT-0) were aged in the multi
stressed aging chamber for 9000h, where they were subjected to multiple
stresses like electrical, humidity, heat, and UV radiation. X-Rays Diffraction
(XRD) was performed to confirm filler presence in composites. Additionally,
the dielectric constant, dielectric loss w.r.t temperature and frequency, DC
resistivity, as well as AC and DC leakage currents, were assessed both before
and after stresses application. Notably, the DC resistivity exhibited a declining
trend after the application of stresses. Furthermore, periodic increments in the
dielectric constant, dielectric loss, and leakage current were observed.
Interestingly, the SiR hybrid composites displayed a degree of resistance to
the aging effects on their electrical properties when compared to the neat HTV
SiR. Among the hybrid composites, the HTV silicone rubber composite
containing 2% nano-silica (SAT-2) showed promising potential for
applications in multi-stress environments over extended durations.
