The mechanism of gas pressure and temperature dependent surface flashover in compressed gas involving gas adsorption

Surface flashover in 50 years: Theoretical models and competing mechanisms

“…Synergetic effects of gas adsorption and surface charging [35][36][37][38]: In 2019, Li et al [35] established a surface flashover model involving the synergetic effects of gas adsorption and surface charging. In the model shown in Figure 1j [35], the relation between gas adsorption and DC surface flashover was first discovered in wide gas pressure and temperature regions.…”

“…Namely, when the applied voltage increases, the distortion caused by the solid is enhanced, which in turn causes the deviation of surface flashover from the gas breakdown as the gas pressure increases (Figure 3d). On the other hand, Li [35,36] attributed the ratios of V f /V b to the synergetic effects of gas adsorption and surface charging. In this case, as pressure increases, the relative adsorption quantities on the surface of the solid tend to be saturated.…”

“… History of surface flashover theories. (a) Secondary electron emission avalanche (SEEA) theory [16], (b) typical SEE curve [17], (c) electron triggered polarisation relaxation theory [18–20], (d) current and outgassing theory [21–25], (e) multipactor to plasma discharge model [26–30], (f) critical field theory [31], (g) diffusion‐limited charge accumulation theory [32], (h) comprehensive analytical theory [33], (i) analogous ineffective region expansion model (i: Surface potential increase due to charge accumulation on the insulation surface; ii: Hot electron migration with the increase of temperature in the insulation near the high‐voltage electrode; iii: Expansion of ‘analogous ineffective region’ due to hot electron migration) [34] (j) surface charging and gas adsorption model [35–38], and (k). Dam‐flood model [39].…”

China's 10-year progress in DC gas-insulated equipment: From basic research to industry perspective

“…Synergetic effects of gas adsorption and surface charging [125] Surface flashover is a complex phenomenon concerning the properties of solid, gas, and gas-solid interaction. Although gas desorption is a triggering factor for flashover in a vacuum, it still lacks the physical process which can unravel the gas−solid coupling mechanism in compressed gas.…”

“…Although gas desorption is a triggering factor for flashover in a vacuum, it still lacks the physical process which can unravel the gas−solid coupling mechanism in compressed gas. To address the underlying mechanisms, a surface flashover model that involves synergetic effects of gas adsorption and surface charging is proposed by Li et al [125] , which is shown in Figure 32. Three essential charge transport processes in multiphase are emphasized in the present model: (1) the electric field is highly distorted near the cathode triple junction (CTJ), electrons in the solid emit into the gas phase and leave large amounts of positive charges in the solid surface layer; (2) surface charge determines the vertical electric field, which greatly affects the collision ionization and electron emission processes in the gas phase; (3) large amounts of gas are absorbed upon insulator surface, the gas density in the gas surface layer gradient decreases with the distance to the surface, the improved gas density impede the collision ionization processes in the gas phase, which further determines surface flashover in compressed gas.…”