The report describes the results of a sensitivity analysis carried out on some parameters (land slope and forest density) in the analytical model of the vulnerability of overhead line spans to the indirect effects of strong winds, developed in the previous System Research.
Vulnerability models of electric cables and oil transformers in case of heat waves are then presented, together with an application example of said models to predict critical network situations, with reference to the heat wave occurred in Milan in June 2019.
After an overview of landslide phenomena, the vulnerability model of network components to superficial landslides – typically rapid landslides induced by intense rainfall – is presented. The model is integrated into the RELIEF tool for the evaluation and improvement of resilience, and then applied in two contexts: the calculation of failure return times (for long-term analysis) and the anticipation of critical network situations (in exercise programming), also with reference to a real landslide event. The risk is modeled using landslide hazard maps and rainfall trigger curves. The simulations show the model’s ability to provide failure return times in line with operational experience, as well as to anticipate the list of network components most likely to fail and the circumstances that contribute most to the risk of user outages.
Further developments in modeling the effects of cyber attacks on the electrical system are then presented, which include the possibility of sending false current measurements of lines and/or switch states to the logic of a defense system for the prevention of cascading events.
Finally, a simulation of simultaneous threats is described, based on a ‘physics-inspired’ modeling of threats interaction, in particular on a flood caused by the failure of a dam due to an earthquake. Simulations carried out with reference to the Alpe Gera dam demonstrate the flexibility of RELIEF in modeling new components (the dam) and its ability to carry out resilience analyses also by interfacing with other tools (in this case, the IRIS program for the analysis of the structural response of dams and a GIS tool with a 1-D forecast model of water heights and maximum speeds related to flooding).