Research of Differentiate Technology and Strategy of Lightning Protection for 500kV Transmission Line JG-type Tower

In view of the transmission line operating experience, the lightning trip rate of 500kV transmission line with JG-type("J" represent it is a corner tower and "G" represent the shape of tower) tower is relatively higher. In order to further improve the reliability of the power grid, and to take reasonable and effective measures in the light of transmission line characteristics, to achieve refined management of transmission lines, it is necessary to carry out differentiate technology and strategy of lightning protection for transmission line with JG-type corner tower. Firstly, Lightning flashover risk evaluation for transmission line with JG-type tower was carried out using the differentiate technology and strategy of lightning protection. The effects of topography and wind speed on the maximum lightning shielding failure current were analyzed. Considering the factors of tower structure, topography, wind speed and ground flash density, the lightning flashover risk was analyzed for the line with JG-type corner tower, and a preliminary lightning protection plan for JG-type tower was developed. Then the lightning protection measures were assessed technically and economically adopting the improved analytic hierarchy process(IAHP). Finally, the optimal lightning protection measures were determined. Through beforehand evaluation of the lightning protection measures, it is shown that if the developed lightning protection plan was implemented, the lightning flashover rate of transmission line with JG-type tower will be decreased by more than 50%.