Space/surface charge accumulation is a potential cause for the decrease of surface flashover voltage of DC GIL insulators. Applying nonlinear conductive coating is an effective method to improve the surface insulation performance. In this paper, a mathematical model was established for the regulation of space/surface charge and surface electric field of insulator by electric field dependent nonlinear con-ductive coating. The nonlinear relationships between the current density of insulating gas and the solid conductivity of insulator and the electric field intensity were comprehensively considered. The internal charge distribution law of insulator under temperature gradient distribution and the influence mechanism of nonlinear conductive coating on the surface charge accumulation of insulator were studied through this model. The results show that the nonlinear conductive coating promotes the dissipation of space charge obviously, and the homopolar charge near the high voltage electrode dominates the surface charge distribution. Due to the improvements of surface charge distribution and tangential electric field, the surface flashover performance improves. The positive charge may accumulate between the insulator and the coating interface, and decrease gradually from the high voltage electrode to the ground electrode.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |