During the summer period, extreme conditions associated with heat waves are increasingly common, inducing significant thermal stresses on underground distribution network components and thus increasing their outage probability. Many distribution companies have emphasized the importance of assessing all potentially critical conditions for resilience, including heat waves – which, together with changing consumption profiles, have resulted in so many outage events that this phenomenon is considered “extreme”.
This study completes the work begun in previous years and an outage prediction warning system for underground distribution lines for the Milan urban area has been structured by combining together the weather forecast (and no longer the reanalysis), the Milan urban area load forecast system, and the outage prediction system. These three components collectively make up the warning system for the city of Milan, which was then subjected to further verification to evaluate the uncertainty components related to weather forecasting, energy load forecasting, and fault forecasting as a whole. The performance of the warning system is lower than that of the single fault prediction model calibrated to the weather reanalysis also due to the different verification system adopted in this study (k-fold cross-validation). However, the system as a whole seems to fairly satisfactorily capture the main outage events associated with summer heat waves for the period 2010-2019. The problem of underestimating the outage peaks in conjunction with the most significant events has been partly solved by applying the statistical quantile mapping methodology downstream of the per-event outage prediction model.
At the conclusion of this study, a climatological analysis of summer heat waves using Euro-CORDEX regional climate models is finally shown. The analyses show a significant increase in the duration, intensity, and frequency of summer heat waves by mid-century, especially over the Po Valley, the inland areas of central southern Italy and the two major islands; the greatest issues concern in particular areas where the most densely populated urban centers are located, due to the high demand for cooling energy.