Nonlinear inelastic responses of transmission tower-line system under downburst wind

• Nonlinear inelastic response of a transmission tower-line system under downburst.
• Capacity curve of a tower within a tower-line system.
• Comparison of capacity curve estimated using different methods.
• Comparison of capacity curve of a tower within a tower-line system to that of a single tower.

Electrical transmission tower-line systems transport the needed electrical energy. These systems are spatially distributed and subjected to extreme natural environmental events such as downbursts. The capacity curve of a single tower has been reported under the downbursts but neglecting the turbulent wind component and potential dynamic tower-wire interaction. This study is focused on the assessment of capacity curve of a tower within the tower-line system considering the turbulent winds and the tower-wire interaction. The incremental dynamic analysis and the nonlinear static pushover analysis are employed to estimate the capacity curve. Moreover, comparison of such a capacity curve to that of a single tower is also presented. It was shown that the turbulent winds introduce variability in the capacity curve. The estimated capacity curve by using the nonlinear static pushover analysis is in close agreement to the average capacity curve obtained based on the curves estimated using the incremental dynamic analysis. Most importantly, it is shown that the capacity curve of a single tower represents adequately that of a tower within a tower-line system, and the effect of the dynamic interaction between the tower and the wires on the capacity curve is negligible.