<p>Silicone rubber filled with low amounts of thermally<br />reduced graphene oxide exhibit non-linear conductivity<br />with exposed to increased electric fields. Such material<br />can be interesting as electric field grading material in<br />HVDC cable accessories. In this study graphene oxide<br />was thermally reduced (rGO) at 120 and 180 °C during<br />12 hours in a hot air oven. The reduction was confirmed<br />by TGA and FTIR. 3 wt.% rGO was then dispersed in a<br />silicone rubber matrix and homogenous dispersion was<br />demonstrated by the scanning electron microscopy. The<br />rGO-filled silicone rubber (120 and 180 °C reduced)<br />exhibited a non-linear resistivity when exposed to an<br />increasing electric (DC) field. The conductivity<br />decreased from 10^14 to 10^11 Ohm m when the electric<br />field increasing from 0.2 to 6 kV/mm. The onset of the<br />non-linear conduction occurred in the range of 1 – 2<br />kV/mm. The long-term stability of the conductivity of<br />the silicone rubber composite was tested. After 47 days<br />ageing at 120 °C, therGO/silicone rubber composite<br />exhibited a slight increase in the onset of non-linear<br />conduction, as well as a minor increase in resistivity.</p>
Research on Improving Electric Field Distribution of Cable Terminal Based on Non-linear Materials
