Characterization of Arc Development of Roof Insulators for High-Speed Trains

The height of the roof insulator structure is generally fixed at 400mm. The umbrella skirt is more dense than the transmission line insulators. Roof insulators are affected by low air pressure, resulting in a significant reduction in its insulation performance and the occurrence of tainted flash, threatening the safety of train traffic. The key to tainted flash is how to develop to flashover after localized arc formation. To this end, the use of artificial climate chamber to carry out the roof insulator local arc development characteristics research. The results show that: as the altitude rises, the insulator arc phenomenon is more obvious, the arc length is smaller. The lower the air pressure, the shorter the time from arc initiation to complete flashover. When γ reaches the critical flashover arc (0.40 ~ 0.55), the arc development speed increases dramatically, the maximum can be up to 109m/s, 138m/s and 189m/s. The research can provide a theoretical basis for the design of high-altitude roof insulator structures.