The regulation mechanism of SiC/epoxy coatings on surface charge behavior and flashover performance of epoxy/alumina spacers

Abstract

Surface charge accumulation on insulators becomes an important bottleneck to restrain the development of a DC energy transmission system. This study investigates the effects of SiC/ epoxy coating on surface charge behaviors and flashover performance of alumina/epoxy spacers. A nonlinear conductive coating consisting of different contents of SiC fillers and epoxy matrix was fabricated and sprayed on only half surface of the spacers. The dependence of surface charges on the contents of SiC fillers is characterized by three stages. Surface charge accumulation is aggravated at deterioration stage, then almost unaltered at balance stage and inhibited at suppression stage. These three stages are determined by the competition between the increased surface trap density from interface region and the improved surface conductivity from SiC fillers. The variation trend of flashover in air and SF 6 /N 2 mixtures is distinguished by three stages as well. Flashover voltage decreases at descent stage where deficient contents of SiC fillers are appended and then goes up at improved stage with moderate supply of SiC fillers. Finally, it ends up with drastically collapse at degenerated stage when affluent SiC fillers are brought in. The theoretical analysis is proposed based on surface trap distribution and conductivity measurement results to reveal the regulation mechanism of SiC/epoxy coating on surface charge behavior and flashover performance.

Gas–solid interface charge characterisation techniques for HVDC GIS/GIL insulators

“…Zhang et al [79] applied this algorithm to measure the surface charge density of the spacer model in GIL. For spacers coated with SiC/epoxy coatings of different SiC mass fractions, surface charge distributions under 0.1 MPa 20% SF 6 /N 2 mixtures under DC voltage are presented in Fig.…”

“…Fig 26. Surface charge distribution under 0.1 MPa 20% SF 6 /N 2 mixtures on different SiC/epoxy-coated spacers after 10 min DC application[79] …”

Study of Compatibility Between Epoxy Resin and C4F7N/CO2 Based on Thermal Ageing

“…The experimental results can also be explained by Xue's model [29]. Before thermal acceleration test, it can be seen that α -Al2O3 particles in the original samples were evenly distributed in the epoxy resin in the form of fillers, as shown in Figure 12(a).…”

Surface charge accumulation and pre‐flashover characteristics induced by metal particles on the insulator surfaces of 1100 kV GILs under AC voltage

“…Moreover, it is generally believed that charge is more likely to accumulate on insulator surfaces under DC voltage, which has a great influence on the flashover characteristics [15][16][17][18][19][20][21]. However, there are few studies on the surface charge accumulation of insulators under AC voltage [16,[22][23][24].…”