Tracking/Erosion Resistance Analysis of Nano-Al(OH)₃Filled Silicone Rubber Insulating Materials for High Voltage DC Applications

Abstract

-HVDC technology has become popular as an economic mode of bulk power transmission over very long distances. Polymeric insulators in HVDC power transmission lines are affected by surface tracking and erosion problems due to contamination deposit, which pose a greater challenge in maintaining the reliability of the HVDC system. In addition, polymeric insulators are also naturally affected by aging due to various environmental stresses, which in turn accelerates the surface tracking and erosion problems. Research works towards the improvement of tracking and erosion resistance of polymeric insulators by adding nano-sized fillers in the base material are being carried out worldwide. However, surface tracking and erosion performance of nano-filled aged polymeric insulators for HVDC applications are not well reported. Hence, in the present work, tracking and erosion resistance of the nano Al(OH) 3 filled silicone rubber insulation material has been evaluated under DC voltages at different filler concentrations and aged conditions, as per IEC 60587 test procedures. Leakage current and contact angle measurements were carried out to understand the surface hydrophobicity. Moving average technique was used to analyze the trend followed by leakage current. Water aged specimen shows less tracking resistance when compared with thermal aged specimen. It is observed that nanofiller concentration of 5% is even sufficient to get better tracking/erosion resistance under DC voltages.

Effect of Filler Concentration on Tracking Resistance of ATH-Filled Silicone Rubber Nanocomposites

“…The results of Figure 6 also demonstrate that the difference in the SCA caused by different filler loading seems to be negligible for the considered micro-sized SiO2 and nano-sized ATH fillers. Such a relationship between the SCA and the filler loading was also reported in [35], which reported SCA measurements for ATH/SiR composites with larger concentration values (up to 30 wt %). considered hydrophobic.…”

“…Measurement results of SCA are shown in Figure 6, while Figure 7 shows the water droplet pictures during the SCA measurement. As discussed in [35], materials with an SCA larger than 90 • are considered hydrophobic and it can be seen from Figure 6 that all specimens have an SCA that is sufficiently larger than 90 • . Hence, surfaces of the prepared micro-and nanocomposites could be considered hydrophobic.…”

“…Figure 9b shows the TGA for nanocomposites with relatively low filler loading (1 wt %, 3 wt %, and 5 wt %) and pure SiR. While the initial weight reduction that starts at around 200 • C could be explained by the water release of ATH fillers [2,35], significant weight decrease occurs as a result of thermal decomposition in the main chemical chain of SiR at temperatures above 350 • C [2]. From Figure 9, in general, it could be said that an increase in the residual weight occurs as the concentration of fillers increases.…”

A review of thermoplastic elastomeric nanocomposites for high voltage insulation applications

“…Recently, Kannan et al published a research work on the tracking and erosion resistance of nano‐Al(OH) 3 filled silicone rubber (SR) insulation material which has been evaluated under DC voltages. Leakage current and contact angle measurements were carried out to understand the surface hydrophobicity.…”

The tracking and erosion performance of silicone rubber incorporated with novel TiO2@SiO2 core-shell nano fillers under the IEC 60587 standard

“…The most common NPs investigated in literature are Aluminum Tri-hydride (ATH) [7][8][9] and silica (SiO 2 ) [10,11]. Aluminum Nitride (AlN) [12,13], Aluminum hydroxide Al(OH) 3 [14] , Boron Nitride (BN) [13,15], barium titanate (BaTiO 3 ) [16] and alumina (Al 2 O 3 ) [17] are also investigated in few studies.…”