Given the increasing frequency and severity of extreme events due to climate change and the higher and higher attention nowadays societies deserve to environmental and economic sustainability, it is fundamental for Transmission System Operators (TSOs) to have: innovative technologies to support power system (PS) resilience and tools and methodologies that can quantify the benefits of resilience enhancing interventions on the electricity grid during the planning phase.

One of the possible solutions adopted by Terna, the Italian TSO, in order to increase power grid resilience, is the installation of remotely controlled and motorized switch disconnectors. These devices allow to reduce the power outage time for a substation in case of out of service when it is connected with multiple ends line (“T-connection” or derivations).

This paper presents the relevant technology and proposes the analytical model of these devices developed by Terna and Ricerca sul Sistema Energetico (RSE) and integrated in their risk-based resilience assessment methodology to quantify the benefits from the installation of these devices. The case study shows the ability of the model to quantify the relevant benefits in the technical-economic assessment and to support Terna in the identification of optimal interventions.