A review of the enabling methodologies for PMUs-based dynamic thermal rating of power transmission lines

In the last years, dynamic thermal rating assessment of overhead lines has gained a critical importance in power system operation, since it allows transmission system operators to reliably increase the exploitation of existing infrastructures, avoiding the construction of new transmission assets, and increasing the hosting capacity of renewable power generators. Amongst the possible approaches that can be adopted to solve the thermal estimation problem, the one based on synchrophasor data processing is considered as one of the most promising enabling technologies, since it does not require the need for deploying dedicated sensing technologies distributed along the line route, but only the availability of synchronized measurements already available in the control centers for supporting wide area power system applications. Anyway, the deployment of this technology in real operation conditions is still at its infancy, and several open problems need to be addressed, such as the accuracy drop in low loading conditions, and the need for properly representing and managing the data uncertainties in the thermal estimation process. In trying to address these issues, this paper presents a comprehensive analysis of the most promising solution methods proposed in the literature, evaluating their performances on a real case-study based on a thermally constrained power transmission line located in the north of Italy.