Differentiate technology and strategy of lightning protection for 220kV transmission line J-type tower

In view of the transmission line operating experience, it is necessary to attach importance to the lightning protection for transmission line with J-type corner tower. Firstly, Lightning flashover risk evaluation for transmission line with J-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 J-type corner tower, and a preliminary lightning protection plan for J-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 J-type tower will be decreased by more than 70%.