The study was developed with the aim of identifying the dynamics that are generated within the joint insulation system in MV cables, especially in the summer period, when the surrounding conditions do not favour the dissipation of the heat accumulated in the component.

Through the facility developed by RSE, in its MV Cable Diagnostics laboratory, it was possible to identify some of the degradation dynamics that can be activated in the insulation system in conditions of dried soil, simulated by felts, and with direct installation in the ground in the presence of different humidity percentages after rainfall of different intensity.

The study was carried out with innovative diagnostic techniques alongside the traditional ones for the detection of  TGδ and partial discharges.

The experience gained allows us to affirm that it is precisely the temperature that plays an important role in the degradation process of the insulating systems: in fact, in self-shrinking joints, it often generates a sliding between the materials with different expansion coefficients, creating places of activity for the partial discharges. In the case of direct installation in the ground, the presence of humidity constitutes a good element of heat dissipation but, in the case in which the hydraulic barriers, created upstream and downstream of the joint, are inefficient, the water penetrates, favouring the process of degradation of the performance of the component that breaks down after a sudden increase in partial discharge activity.

During the year, particular attention was dedicated to the development of tools capable of facilitating the management and maintenance of the electricity distribution network, increasing its resilience and reducing inefficiencies for the end user, in particular they were developed, in collaboration with the University of Trieste, a prototype system suitable for both off-line acquisition and one dedicated to monitoring partial discharges. In addition to the hardware part, software has been developed which, although still in the beta-test version, allows us to interpret the possible causes that trigger the activity of partial discharges in the component.

This tool will be the subject of in-depth studies and dedicated checks that will be carried out during the next year of research in order to increase the efficiency and reliability of the prototypes and then make them available to all Stakeholders who can increase their own methodologies and tools for management and maintenance of the electricity distribution network, increasing its resilience and reducing inefficiencies for the end user.

This need arises from the fact that the commercial tools available today allow limited signal processing spaces which in most cases are made available in proprietary formats.

The document is available on the site in Italian