Risk based design of distribution line structure

Abstract

Power overhead line regulations and codes generally apply prescriptive methods to the design of structures using working loads multiplied by factors of safety. In contrast, the probabilistic method is founded on designing to a limit state in which strength is matched to stress, with the risk of failure defined by the overlap of the distributions of the limit state model. This work indicates how a stress limit state using probability concepts can be applied to the design of round pole distribution line structures. It indicates that unlike the transmission line, variations which occur in the layout of distribution lines necessitate the use of some contingency factors. Design studies of new and existing lines show that there are substantial savings to be made.