A Digital Twin Architecture for Monitoring Medium Voltage Distribution Grid: The Real-Time State Estimation Use Case

During the last decades, Medium Voltage (MV) and Low Voltage distribution systems have become increasingly complex due to the increasing penetration of Renewable Energy Sources and – more in general – distributed resources such as evehicles. Therefore, better monitoring and control tools are required. This paper discusses how Digital Twin (DT) architecture for MV distribution grids can improve management, presenting the benefits in a specific use case: State Estimation (SE). This approach has been applied to the distribution grid of Unareti S.p.A., an Italian Distribution System Operator (DSO) operating in northern Italy and serving over one million customers. The suggested architecture combines real-time field measurements, a very detailed virtual model of the physical grid, and an SE algorithm all embedded into Advanced Distribution Management System (ADMS) which is also fully integrated within a more general Information Technology/Operational Technology (IT/OT) ecosystem in order to become a DT. This DT framework enables continuous synchronization with live grid conditions, enriching network observability and improving estimation accuracy, even in areas with a low percentage of monitoring devices. The presented case study focuses on a HV/MV primary substation managed by Unareti and demonstrates the capability of the architecture to deliver real-time state estimations in a real operating environment. The mean percentage error of the SE algorithm is $-4.9 \%$ and the standard deviation is $13.3 \%$.