Simulation Study on Two Anti-corona Schemes of Grading Ring with Non-ideal Surface Morphology

The grading rings working in complex environment are often reported with corona discharge. Their surfaces are often found with non_ideal surface morphology affected by wind erosion and/or dirt accumulation. To reduce corona discharge of these grading rings operated online, two anti-corona schemes, grinding and RTV(Room Temperature Vulcanized Silicone Rubber) coating, are proposed. Through analyzing the simulation results, it is found that the two schemes can improve the surface electric field to achieve the purpose of anti-corona. After comparing the two schemes, RTV coating scheme shows more obvious to reduce the maximum electric field intensity of the surface than the grinding scheme, and RTV coating is easier than grinding to be implemented in engineering practice.