Conseil national de recherches du Canada. Centre de recherche en métrologie
silicone rubber; DC erosion resistance; DC inclined-plane test; dry-arc resistance test; fumed silica barrier effect
This paper investigates the filler barrier effect on suppressing the erosion of silicone rubber composites during the DC dry-band arcing, by supplementing main micro fillers in silicon rubber, i.e. ground silica and micro-sized alumina tri-hydrate, with fumed silica and nano-sized alumina tri-hydrate fillers. A study framework employing simultaneous thermogravimetric-differential thermal analyses, the inclined plane tracking and erosion test and the dry-arc test is employed. Fumed silica in silicone rubber increases the amount of the crosslinked residue and suppresses silicone rubber depolymerization; whereas nano-sized alumina tri-hydrate releasing water of hydration may adversely impact the residue coherence and promote combustion. The viability of the filler barrier effect is synergistically achieved by adding fumed silica to the main ground silica filler, thereby maintaining the residue integrity. The inclined plane-tracking erosion test confirms the importance of the filler barrier effect of fumed silica in supplementing the volume effect of ground silica in the suppression of the DC dry-band arcing. These filler effects appear to mainly govern the erosion resistance, with insignificant effect shown for thermal conductivity under DC. The dry-arc resistance test is shown as a useful method to simulate a stable dry-band arcing and obtain reproducible surface erosion patterns that correlates with the outcomes of the DC inclined plane tracking and erosion test.
Date de publication
IEEE Transactions on Dielectrics and Electrical Insulation (24 août 2022).