High flashover strength and superhydrophobic coatings by constructing porous surface structure

Abstract

Flashover is prone to occur in composite insulation structures such as vacuum‐solid and gas‐solid, which are universally employed in high‐voltage power equipment. In this study, a high flashover strength and superhydrophobic coating were proposed by constructing porous surface morphology. Octadecyl trichlorosilane (OTS) particles were prepared by hydrolysis condensation reaction, and thereafter sprayed onto the substrate surface to form a porous and rough surface structure with hundreds of nanometres of dispersed pores and pits. The coating endowed epoxy resin with maximum 44% flashover voltage increase and the superhydrophobic surface with water contact angle of 158.4°. Since the pore size in OTS coating is close to electron mean free path in atmospheric condition, the collisional ionisation can be effectively hindered, which suppresses the micro‐discharge around the triple junction and improves the flashover strength. The present approach provides a new insight for simultaneously improving flashover strength and superhydrophobic properties of dielectric insulation.

Study on surface discharge of nonlinear conductive epoxy resin/SrTiO3 composites in 80–300 K temperature zone

“…At this time, the proportion of shallow traps in the composite is increased, so the charge trapped by the trap during the secondary electron multiplication process can be dissipated faster. It greatly reduces the degree of charge accumulation on the surface of the insulating material under the action of DC voltage and increases the flashover voltage amplitude to a certain extent [45]. At the same time, the EP composites modified by nano‐SrTiO 3 have non‐linear conductivity characteristics, and their conductivity tends to increase with the increase of filling content and external electric field strength.…”

The mechanism of EP/SiC coating modulated DC flashover characteristics of epoxy composites in SF6/N2 mixtures

“…Compared with other methods, surface coating effectively and directly replaces the insulation properties of epoxy-based insulators with another material without any byproducts. To date, two types of coating materials, namely, low-conductivity and high-conductivity materials, have been used for surface modification to improve the surface insulation performance [14][15][16]. For low-conductivity materials, materials with better insulation properties are used to coat the ceramic insulator [17][18][19].…”

Surface flashover in 50 years: Theoretical models and competing mechanisms

“…Surface flashover that accompanies a large amount of energy loss generates an arc along the gas-solid interface, and the arc ablates the surface of the insulator, which causes the insulation failure of the surface of a material, and further influences the safe operation of relevant equipment. Therefore, surface flashover is a great threat to advanced applications in various fields, such as basintype insulators and vacuum interrupters in gas-insulatedswitchgear (GIS) [5][6][7][8]/gas-insulated-lines (GIL) [9][10][11], space solar power stations in spacecraft [12,13], high-voltage (HV) pulse applications [14,15], particle accelerators etc. Hence, it is of significance to clarify the surface flashover development process and offer guidance to improve surface flashover performances.…”