A Frequency-Domain Method to Assess the Dynamic Buffeting Response of Transmission Lines Under Downburst

A downburst is a short-term, sudden, and strong wind event that causes numerous transmission line failures worldwide. This paper applies random vibration theory to investigate the dynamic buffeting response of transmission lines subjected to downbursts. The total response is decomposed into static and dynamic components, with the time-varying mean response calculated analytically. In contrast, the dynamic response is considered as the quasi-static background response and is computed by the influence function. Based on the quasi-static assumption, equations for calculating the mean square deviation of the time-varying mean response and the pulsation response of transmission lines under both equal and unequal elevation conditions are derived through coordinate transformation. A case study is conducted in the frequency domain using simulated downburst wind velocity time histories. Further analyses are carried out by the time-domain nonlinear finite element method (FEM) to investigate the effects of structural geometrical nonlinearity and aerodynamic damping on the response of the transmission line to downbursts. The time-domain results are compared with the analytical solution to verify the correctness and applicability of the present method.