Preparation and Dielectric Properties of SiC/LSR Nanocomposites for Insulation of High Voltage Direct Current Cable Accessories

Abstract

The conductivity mismatch in the composite insulation of high voltage direct current (HVDC) cable accessories causes electric field distribution distortion and even insulation breakdown. Therefore, a liquid silicone rubber (LSR) filled with SiC nanoparticles is prepared for the insulation of cable accessories. The micro-morphology of the SiC/LSR nanocomposites is observed by scanning electron microscopy, and their trap parameters are characterized using thermal stimulated current (TSC) tests. Moreover, the dielectric properties of SiC/LSR nanocomposites with different SiC concentrations are tested. The results show that the 3 wt % SiC/LSR sample has the best nonlinear conductivity, more than one order of magnitude higher than that of pure LSR with improved temperature and nonlinear conductivity coefficients. The relative permittivity increased 0.2 and dielectric loss factor increased 0.003, while its breakdown strength decreased 5 kV/mm compared to those of pure LSR. Moreover, the TSC results indicate the introduction of SiC nanoparticles reduced the trap level and trap density. Furthermore, the SiC nanoparticles filling significantly increased the sensitivity of LSR to electric field stress and temperature changes, enhancing the conductivity and electric field distribution within the HVDC cable accessories, thus improving the reliability of the HVDC cable accessories.

Dielectric and Thermal Conductivity Characteristics of Epoxy Resin-Impregnated H-BN/CNF-Modified Insulating Paper

“…A DC breakdown strength test was conducted using a cylindrical electrode, in accordance with ASTM-D149. The temperature was maintained at 298.15 K. The entire test system was placed in transformer oil to avoid surface breakdown [ 18 ]. The average breakdown strength and standard deviation of 15 samples were used to evaluate the breakdown performance.…”

Dielectric and Thermal Conductivity of Epoxy Resin Impregnated Nano-h-BN Modified Insulating Paper

“…In addition, high-voltage generators and column polar structure, in compliance with the standard ASTM-D149 were applied during the DC breakdown strength tests, and the entire testing system was placed in transformer oil, at the temperature of 298.15 K [23]. Both the height and the diameter of the electrode is 25 mm.…”

Performance of Silicone Rubber Composites Filled with Aluminum Nitride and Alumina Tri-Hydrate

“…High-temperature-vulcanized silicone rubber (SR) is widely used to manufacture high voltage insulators due to its relatively light weight and excellent anti-contamination ability [1][2][3][4]. It is often filled with suitable additives so that the performance of the SR composites can be improved [5][6][7][8][9][10][11]. To date, alumina tri-hydrate (ATH) has been one of the most commonly used fillers in SR composites, which can endow the composites with good flame retardancy and erosion resistance.…”