Corrosion in low-voltage distribution networks and perspectives for online condition monitoring

The low-voltage distribution grid is an essential link for the integration of distributed renewable sources. It is expected to experience stronger loading and load variation in the near future. At the same time, part of the low-voltage network is an aging infrastructure. Distribution system operators are therefore becoming increasingly interested in being able to diagnose their low-voltage assets. This paper describes corrosion phenomena that are observed in aluminum conductors after a damage is inflicted to a cable section. Such a damage is suspected to initiate long-Term degradation. Short-duration intermittent current peaks are observed in laboratory experiments and similar peaks are now also recorded in the field. The perspectives for online monitoring, by registering these events, are investigated by having a large number of measurement devices installed on connections in service. The research is directed to gain a better understanding of the relation between the current peaks and cable circuit failures as well as the underlying degradation mechanisms.