Enhanced Monitoring System for Black Start Tests Using High Frequency Data Acquisition and Processing to Real Case in the Italian Transmission System

Terna, the Italian Transmission System Operator (TSO), started a project aimed at monitoring of this kind of transient phenomena occurring in the power-system especially during black-start phase and implemented CoSMo (Coordinamento Sistemi di Monitoraggio – Monitoring System

Coordination) system as a solution. The project takes advantage of new technologies, increased processing capability of automation controllers and communication network capacity to enable real-time and high frequency (of the order of kilohertz) analysis of voltages and currents, with a focus on critical transmission lines in different key locations of the Italian electricity transmission system. The availability of continuous high frequency sampled data also enabled the implementation of dedicated power quality applications, which are now integrated into the

CoSMo system.

This paper describes the system architecture, visualization software, and the underlying communications system demonstrating how the CoSMo project has significantly increased operator awareness. After recalling the main features of the solution adopted, including plan to integrate cybersecurity functionalities, the paper describes its successful application to real cases in the Italian Transmission System during black start tests. Presented results demonstrate the ability to measure and monitor transient phenomena, enabling the detection of highfrequency components and dynamic behaviors compared with conventional 50 Hz PMU monitoring systems. The enhanced resolution provided by the CoSMo monitoring solution allowed for a more detailed characterization of system response during black start operations, supporting the identification of critical events, improving situational awareness, and contributing to the development of more robust protection and control strategies.