A capital light solution to increase power system resilience against wet snow: the Italian experience with anti-torsional devices

Given the uncertainty of global scenarios related to political, health, and environmental aspects, and the consequent focus on both environmental and economic sustainability, it is crucial for Transmission System Operators (TSOs) to have the tools and methods capable to adequately assess the benefits of grid interventions under planning, also forecasting critical conditions in the grid, especially those associated to extreme weather events, whose frequency is increasing due to climate changes. The concept of resilience thus plays a key role in adequately coping with extreme weather events and in improving system performance. The present paper describes the anti-torsional devices, a capital light measure to strengthen the power system infrastructure against wet snow events, and their in-field installation. In order to quantify their benefits, a model of these devices is proposed and applied in the Terna-RSE risk-based methodology aimed at evaluating investments to increase power system resilience. The case study applied to a model of a realistic EHV/HV transmission system demonstrates the model effectiveness and the potentiality of the tool used by Terna to perform a quantitative techno-economic assessment of the portfolio of resilience boosting measures.