Umbrella Skirt Design of Oblique Cantilever Composite Insulator Suppressing Icicle Bridging for High-Speed Railway

When icing occurs on the oblique cantilever insulator of the high-speed railway contact line, the ice column that develops downward from the edge of the small umbrella connects with the edge or surface of the large umbrella, which can reduce the creepage distance and even induce flashover failures in the insulator. This article designs an irregular umbrella skirt oblique cantilever insulator, oriented vertically to the horizontal plane, based on an analysis of the droplet sliding trajectory and ice column growth process on the surface of existing oblique cantilever insulators. A model of the irregular umbrella insulator is produced using 3-D printing, and its surface is coated with room temperature vulcanized silicone rubber (RTV). Experimental results show that, during droplet sliding on the optimized irregular umbrella skirt surface, the large umbrella of the irregular umbrella insulator is not bridged by the ice column. Compared to the original insulator model, the flashover voltage of the oversized umbrella irregular umbrella insulator model is increased by 5.44 kV. The research findings can provide a reference for reducing icing-flashover failures in oblique cantilever insulators under low-temperature and high-humidity environments.