Accurately assessing the vulnerability of network components to threats is key for quantifying the resilience of the electricity system in the face of both anthropogenic and natural threats.

This report proposes an advanced model of vulnerability of overhead lines that considers the combined action of strong wind and wet snow, evaluating both the direct actions of threats on the line subcomponents and the indirect actions due to vegetation interfering with the line.

The vulnerability curves generated for some lines of the Italian transmission network provide insights consistent with the operators’ experience. The models can be applied both for long-term analysis (calculation of the return times to failure of the components) and in support of the planning of the operation based on weather forecasts. Furthermore, the benefits brought to the resilience by a change in the maintenance procedures of the cutting strip can be quantified via these analytical vulnerability models.

A vulnerability model of insulators to salt pollution is also described, with reference to two pollution-induced flashover mechanisms: the deposition of pollutants in humid conditions and the accumulation of conductive snow on the insulators’ surface. Also in this case, the simulations show the models’ applicability in the operation programming and planning phases. Finally, a methodological approach is proposed to quantify the effects of cyber attacks on network defense systems. Starting from the ICT infrastructure of a specific defense system, in the context of the RdS 2.3 project, the conditional “malfunction” probability of each substation subject to a request for intervention by the defense system, following the cyber attack, is evaluated. By exploiting the theory of binary variable copulas, the methodology presented in this report calculates the probabilities of certain combinations of substation malfunctions and, for each combination, evaluates the risk of de-energized load in the face of a severe contingency that triggers the defense system.

Future developments include the development of vulnerability models for flood-induced landslides and heat waves, and a refinement of the model of the effects of cyber attacks on power system control, protection, and automation systems.