Assessment of Weather Induced Transmission Line Loads on a Probabilistic Basis

The application of the probability-based method to the design of overhead transmission lines is increasingly being considered by engineers as a viable alternative to the current deterministic design method. The deterministic approach in general is based on criteria believed to be conservative enough to attain the required design goal, and cannot assess quantitatively the line security level. The new approach represents more realistically the variability of the load on a structure and its strength than the conventional method and can assess the failure risk directly. In order to apply the probability-based method to overhead transmission lines the design parameters should be represented on a probabilistic basis. In this paper, procedures are given for derivation of probabilistic models for wind and ice loads from meteorological data and transmission line details.