Overhead Electrical Conductors

In elementary mechanics textbooks, power lines are generally given as a typical example of a so-called “flexible cable”. However, in the design of these critical elements of a power grid  it is often necessary to take into account the conductor bending stiffness, or flexural rigidity. While relatively low compared with a bar having an equivalent solid cross-section, it does have some influence on a conductor response to wind excitation, in particular from the fatigue strength point of view.

Depending on the application, several approaches are available. The attached report is a review of mechanical models based on Coulomb’s laws of friction, where a given layer of a multilayer conductor starts slipping when the conductor centerline curvature reaches a critical value. Originally, these theories were developed for cable applications (such as ropeways).