Outage severity analysis and RAM evaluation of 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 with the aim to drive the prioritization of the failure causes and the enhancement of the maintenance activities. The analysis has been performed focusing on the geographical distribution of the OHTLs. For each analyzed region, the voltage levels more prone to failure have been determined. 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 enhancement of the related maintenance activities. Finally, an evaluation of the reliability, availability, safety and maintainability (RAMS) of the Italian OHTL network has been performed from a regional point of view.