Abstract:

Contrastive analysis on lightning protection characteristics of overhead transmission line can be the reference for the lightning protection strategy of transmission line. Taking 110 kV to 1 000 kV AC transmission lines and ±500 kV to ±800 kV DC transmission lines in China as analysis object, the characteristics of back striking and shielding failure were analyzed, and the lightning protection keys for overhead transmission lines with different voltage grades were proposed. For the 110 kV and 220 kV AC transmission lines, back striking should be focused on. For the 500 kV and 750 kV AC transmission lines, back striking should be focused on in the area with high grounding resistance and shielding failure should be noticed in mountain area. For the 1 000 kV AC transmission lines, due to the low flashover rate of back striking, the construction cost could be reduced by applying the natural grounding body of the tower, and it also should focus on the shielding failure of side conductors in mountain area. For ±500 kV, ±660 kV and ±800 kV DC transmission lines, the shielding failure flashover in mountain area should be focused on.

Key words: overhead transmission line, voltage grade, lightning protection, back striking, shielding failure, grounding resistance, protection angle, terrain