Research on security distance of live working on distribution line at high altitudes

Live-working is an important method in ensuring safety operation of distribution network. Although live-working has been successfully applied in many low-altitude distribution lines, there is some technology problems of live line maintenance in high-altitude areas, such as the lack of essential parameters on safety working distance. Along with the increasing altitude, the air gap discharge voltage will decrease, which is the key factor on researching safety working distance of live working. In this paper, experimental study on safety distance of live working was carried out in high-altitude areas for distribution line. Frequency and Switching impulse discharge characteristics tests of live working in different shot gap positions for distribution line were performed in Yangbajing, Tibet (4300m), Lhasa, Tibet (3600m), Nyingchi, Tibet (2900m), Wuhan, Hubei (28m) respectively. The discharge characteristic curves under different work conditions were given. According to the above test results and the existing research in low altitude areas for distribution line live working, the required live working minimum safety distance within the range of altitude 3000m~4500m for distribution line are calculated and analyzed by combining with the common altitude correction methods.