Outage severity analysis on Italian overhead transmission lines from a regional perspective

Power transmission lines represent the core of the High Voltage Network since they are responsible for the transport of the electrical energy from the generation power plants to the electrical substations. In this paper, an analysis of the outages occurred to the Italian Overhead Transmission Lines (OHTLs) from 2008 to 2015 is carried out. A new simple and effective reliability index, namely the Severity Factor, is introduced in order to prioritize the most relevant outage causes. The analysis has been performed focusing on the geographical distribution of the OHTLs. The obtained results have shown that the impact of the different outage causes on the OHTLs reliability is generally not uniform across the country but depends on the considered region. Further, for each analyzed region, the voltage levels more prone to failure have been determined. It can be concluded that the proposed methodology, thanks to the introduction of the Severity Factor, is a useful and effective tool for the identification of the transmission network criticalities and the enhance of the related maintenance activities.