Study on the Charge Dissipation Characteristics of the Gas-Solid Interface of the Nano-Coating of DC GIL Insulators

The gas-solid interface of the insulator is the weak link of the DC GIL insulation system, and the surface of the insulator is prone to charge accumulation. In this paper, SiC/Epoxy composite coatings with different nano-doping content were prepared and applied to the surface of the insulator. The results showed that when the content of nanofillers is low, the dispersion in epoxy resin is more uniform; the thermal stability of composite coating materials is significantly improved. As the content of nanoparticles increases, the surface charge dissipation of the insulator increases; but after a certain value, the surface charge dissipation rate will decrease, even lower than the dissipation rate of pure epoxy resin. When the content of nano-SiC is 6%, the surface charge dissipation speed of the sample is the highest, the charge dissipation rate is the highest, and the final dissipation is about 30% ~ 35%. Analysis suggests that when the content of nanoparticles is low, some shallow traps are introduced into the composite material, which reduces the energy level of the shallow traps, thereby increasing the dissipation rate of the charge. But when the content of nanoparticles is too high, due to factors such as agglomeration of nanoparticles, the distribution of shallow traps is changed.But the charge dissipation is inhibited.Based on the test results of the physical and chemical properties and electrical properties of the nanocomposite coating, a suitable nano-coating can be selected, which is of great significance for ensuring the safe and reliable operation of DC GIL.