Reliability of Utility Structures: A State-of-the-Art Review

Climactic loads imposed on transmission and distribution line systems include ice, wind and ice concurrent with wind. Structural reliability under the action of such loads depends on the statistical variations of the applied loads and associated resistances. This paper reviews the present state of the art in methodologies, techniques and approaches for reliability assessment of utility structures. Current research on wind speed and ice thickness statistical distributions, evaluation of risks, probabilistic models, MRIs (recurrence intervals) and mandatory design standards, along with focus areas for future work, are discussed. Suggestions for future extensions of the methodologies – to line segments and then to the overall utility grid – are given.