Disruption risk analysis of the overhead power lines in Portugal

Abstract

The growing increase in frequency and intensity of extreme weather events (EWEs) has a wide impact on energy systems and consumers, as energy transmission infrastructures - overhead power lines (OPL). The main objective of this work is to present the methodology of risk analysis of the EWEs on OPL in Portugal. The level of risk associated with each of the identified events is classified according to the probability of occurrence and consequences, in a risk matrix, and through the cause-and-effect analysis. It is concluded that, in Portugal, the extreme wind – corresponding to level 11 of the Beaufort Wind Force Scale, that is, values equal to or higher than 105.1 km h- 1 (29.22 m s-1) – is the main factor that provoked the OPL disruption, between 28% and 40% of analyzed events associated with windstorms. Considering the occurrence of compound events - wind and rain - the probability of damage to OPL is between 21% and 30%; for wind and ice, it is 3%–5%. EWEs represent a serious risk for electrical systems, and it is necessary to develop effective solutions to minimize the associated impacts, such as the modification and upgrade of the current design and engineering standards, and electrical network monitoring.