高海拔环境列车车顶绝缘子闪络特性研究OA

[Objective]Roof insulators are key devices for ensuring the safe operation of electric multiple units.When trains operate in high-altitude regions,the roof insulators are completely exposed to the atmosphere,and their insulation performance is significantly reduced due to environmental factors such as low air pressure and natural pollution,threatening operational safety.[Methods]Therefore,the alternating current(AC)flashover characteristics of four types of roof insulators under high-altitude low-air-pressure conditions ranging from 498 m to 5 000 m were investigated using artificial climate chamber tests.[Results]The results showed that the air pressure characteristic indices n under the pollution flashover voltage for the four types of roof insulators were 0.748,0.786,0.719,and 0.698,respectively.Compared with line insulators,roof insulators were more prone to arc drifting under low air pressure,and the arc easily bridged between sheds to form an air-gap arc,resulting in larger n values for roof insulators.For every 1 km increase in altitude,the withstand voltage of the tested roof insulators decreased by about 8.98%,9.43%,8.63%,and 8.38%,respectively.[Conclusion]The research findings can provide technical references for the design and configuration of roof insulators for high-altitude railway trains.