Extreme Weather Conditions Effects On Underground Cable Joints Failures: Strategies For Reliability And Resilience Improvement

In recent years, an abnormal increase of faults in underground Medium Voltage (MV) cable joints has been recorded, especially during summer, by distribution system operators in Italy and worldwide. To preserve an adequate level of reliability and resilience, the causes of such failures have to be investigated to find the most appropriate countermeasures in terms of technological improvement and new planning and operation approaches. Based on the field experience gained by Unareti on Milano and Brescia distribution networks, this paper reports the main results of the analysis of extreme weather conditions' effects on MV underground cable joint failures. Moreover, actions making in place by Unareti, the distribution system operator of Milano and Brescia, for reliability and resilience improvement are listed. The gained information could help redesign innovative, more robust, and resilient joints for MV underground cables and guide distribution system operators in rethinking their distribution network planning and operation paradigms.