Differential lightning protection research on ± 800kv UHVDC transmission lines

Abstract

This paper carried out the further research on differential lightning protection of UHVDC transmission lines, which was based on the ±800kV UHVDC project from Qinghai to Henan. According to the design parameters at the construction stage, the lightning protection performance of the project was studied, and the backflashover rate and the shielding failure flashover rate were given in this paper. By comparing the calculation results of this project and the projects already built, the rationality of the simulation calculation results was verified. In this paper, the mountainous terrain is classified, and the principle of electrical geometric model (EGM model) is used to research the shielding failure flashover rate deeply under different mountainous terrain. Because the whole transmission line of the project was located in the thunderstorm area, the vulnerable section was proposed based on the ground inclination angle, and the lightning protection differentiation measures were proposed for the vulnerable section. After the lightning optimization measures were adopted, the lightning flashover rate of transmission line from Qinghai to Henan was almostly reduced to 0.1 times/100km in 40 thunderstorm day area, which meet the requirements of the standard named as “guide for lightning protection of overhead transmission lines”. The results obtained in this paper can be used as the reference for engineering design.