Abstract：Analysis of transient characteristic of lightning strikes transmission line towers is of great significance to the lightning protection design. This paper takes ±800kV DC transmission line as an example,using EMTP transient simulation software to establish continuous multi-wave impedance model of high towers and Tower-based refining model,building the simplified model of the dc transmission line,analyzing the effects of Lightning current amplitude and Lightning wave steepness on top potential and insulation then calculating the level of against lightning. The results show that the finer tower segment the tower over-voltage amplitude is lower than lossless transmission line model,lightning current wave steepness is closely related to the lightning protection of high tower. When the tower struck by lightning,the voltage at both ends of positive wire insulator strings always higher than that of the anode wire insulator strings,the insulation performance of positive and negative two-tier wire is unbalanced insulation,the influence of the dc voltage can not be neglected.
2015, Vol. 16 
