Enhancement of electrical treeing and partial discharge characteristics of silicone rubber filled with silicon nitride nanoparticles

Abstract

Silicone rubber (SiR) is widely deployed as a high voltage electrical insulating material when compounded with nanofillers. Nanofillers have been introduced into the SiR matrix to prevent such long-term degradation known as electrical treeing. To date, studies on SiR nanocomposites have been intensively conducted incorporating nanofillers from silicon oxide-based. However, only limited studies have reported the electrical tree characteristic correlated with partial discharge (PD) activities in SiR filled with silicon nitride (SiN) nanoparticles. Thus, this study explores the collective gap by characterizing the prolongation of electrical treeing that correlates to the SiR nanocomposites' PD activities filled with SiN nanoparticles. The treeing experimentations were conducted by applying 12 kVrms of 50 Hz AC alternating voltage on the specimen of SiR nanocomposites filled with 1, 3, and 5 weight percentages (wt%) of Si3N4. All the treeing specimens were prepared based on the leaf-like configuration involving a needle-plane electrode arrangement. The electrical treeing growth was analyzed according to the tree initiation time, tree propagation time, growth rate, and tree breakdown time associated with the PD activities. The outcome from this study found that the SiR/SiN nanocomposites were able to withstand the electrical tree growth better than the pure SiR. It can be summarized that the existence of nanoparticles inside the SiR matrix governed the pattern of electrical treeing growth to become a more zig-zag-like structure. Meanwhile, SiR nanocomposite filled with 5 wt% of SiN showed the most effective configuration of nanocomposite with the highest number of branches and the longest time interval for the sample to reach the bridging phase.1