Overhead lines are typically designed to withstand the forces of extreme weather loads such as wind, ice, snow and combinations thereof, based on expectations of periodic meteorological conditions. With the understanding that a line can be susceptible to extreme weather loads that may exceed its design parameters within its lifespan, the consequences of a failure of a component on the line must also be considered that can affect adjacent components. Resulting progressive failures are commonly known as “cascades,” or the failure of one or more components resulting from changes brought about by an initial or originating failure.

This recent CEATI report provides cooperative engineers a guide for assessing the design loads on anti-cascading structures that are normally placed at recommended intervals in the straight sections of line to minimize damage due to cascading failure during extreme events and the optimum placement of those containment structures.