Modeling the Impact of Adjacent Spans in Overhead Distribution Lines on the Wind Response of Utility Poles

Overhead distribution lines supported by utility poles are vulnerable against strong winds. Performance assessment of these systems requires accurate models for various involved components and the system as a whole. Considering that distribution lines are very long and consist of a large number of spans, modeling the entire system is practically not feasible. To address this challenge, this study develops analytical models to capture the boundary effects of adjacent spans on the segment of interest in distribution lines. The proposed model includes equivalent springs and equivalent wind forces to be applied at the boundaries of distribution line segments. The method considers geometric nonlinearities in the response of conductors through an exact solution for their deformed shape under gravity and mean wind speeds. Furthermore, a simplified solution for the deformed shape of conductors is derived and shown to accurately approximate the exact model. These solutions are used to develop a set of stiffness matrix and force vector to simulate the wind response of distribution line segments. Equivalent springs and wind forces representing the boundary effects of neighboring spans are derived considering the variation in the stiffness of the spans and the corresponding wind-induced forces over the length of distribution lines. This approach provides an accurate yet practical method to account for the boundary effects of adjacent spans on the response of utility poles and segments of distribution lines.