Study on lightning strike performance of ± 800kV UHV DC transmission lines in high altitude areas from 4300m to 5500m

In the future, UHV DC lines will pass through more high-altitude areas, with the highest altitude approaching 5500m. The overall elevation poses new challenges for the design and construction of UHV DC lines. At present, the highest altitude of existing UHV DC projects is 4300m. The existing engineering experience, standards, specifications and test data cannot guide the lightning protection of UHV DC lines at higher altitudes. So it is necessary to carry out systematic research on the key technologies for lightning protection of UHV DC lines at higher altitudes. In this paper, the shielding failure and back flashover for lightning withstand performance of ± 800kV UHV DC transmission lines in the area from 4300m to 5500m above sea level in the complex micro terrain and geomorphic environment was studied. The simulation calculation results were given. According to the difference between the calculation results and the standard, the differential lightning protection strengthening measures were given. By taking different lightning protection measures, the lightning flashover rate of ± 800kV UHV DC transmission lines from 4300 to 5500m altitude was controlled below 0.1 times/(100km. a). It has laid a solid foundation for lightning protection of ± 800kV UHV DC transmission lines in the high altitude area from 4300 to 5500m.