Propagating the uncertainties of the overhead line span vulnerability model up to the failure return period in case of extreme events

The operation of electric power systems may be affected by the failure of system components due to adverse weather events. Consequently, the assessment of the "resilience" property, meant as the ability to limit the extent, severity, and duration of system degradation due to such disruptive events, becomes a fundamental task. In resilience analyses, uncertainty sources should be properly represented and quantified. This work proposes an approach based on the Point Estimation Method (PEM) to assess the probability distributions of the failure return periods of overhead line spans, starting from the uncertainties in the span vulnerability model. The approach is applied to three transmission lines exposed to wind loads. Results show that PEM is suitable for uncertainty propagation in the resilience assessment methodology. In particular, different behaviors of the spans are highlighted, in terms of uncertainty of their failure probabilities.