Analysis on Secondary Stress for Steel-Tube Tower of 1000 kV Double Circuit Transmission Lines on Same Tower

The course of Chinese first 1 000 kV UHV double AC tower–SZT2 full-scale test is introduced. Appling transmission tower design software, modeled tower-SZT2 with link element. Based on FEA software ANSYS, SZT2 steel-tube tower models with beam-link element are presented, the two calculating results are compared with the testing results, the distributions of secondary stress and the influences on tower-SZT2 behavior of total structure are analyzed. The results indicate that, it is tower-SZT2 main member gradient changed that influenced by secondary stress most, in other condition invariable situations, the percentage of secondary stress influences is reduced with the increase of rate of length to steel-tube’s diameter, the percentage of secondary stress on several members has reached 30%, it should be considered in design.