The report addresses research aimed at developing methodologies and technological solutions for detecting the condition of air-insulated systems and improving their dielectric performance to enhance the resilience of the electrical grid under critical environmental contamination conditions.

The activity is organized into several areas primarily focused on providing systems to monitor ground leakage currents of insulators in the presence of contaminant accumulation and degradation phenomena, to assess their useful life. The information examined is crucial for enabling network operators to implement appropriate intervention strategies both during the design phase and in the management of the installations.

In particular, the activities carried out included:

Testing different types of insulators at the LANPRIS station to evaluate and compare the performance of four different insulation types.
Finalizing the McMel device for monitoring insulation contamination levels and installing it for field verification.
Optimizing the AMICO DC device, a reference system for monitoring environmental contamination levels.
Characterizing insulators in the laboratory with total and partial RTV coatings through multi-stress aging tests and comparing these with field experiments.
Testing the ILCMS monitoring system for HVDC lines under overvoltages from lightning and switching.
The results of these activities have provided valuable insights into the behavior of different insulators under high levels of environmental contamination: all insulators show threshold levels of leakage currents that persist for most of the time, with significant increases in current beyond this level. Of particular interest is that for composite insulators and those with total coatings, the threshold current levels do not vary significantly with leakage line. However, this must be correlated with the physical degradation of the silicone coating and dielectric performance, which will be assessed through upcoming laboratory inspections and characterization of the insulators.

Regarding the McMel and AMICO DC devices, the first case has reached a final prototype version, and the second has reached an optimized version following field experience. In both cases, the systems are remotely manageable, as required for their installation in an unattended location.

The multi-stress electrical aging tests on various configurations of insulators with total and partial RTV coatings in alternating current (AC) have shown maximum current values similar to those in direct current (DC) tests but with completely different patterns and, importantly, almost no degradation, unlike DC tests. Additionally, the current values between total and partial RTV solutions do not seem to differ from each other, unlike the values observed at the LANPRIS station. Further aging tests (with the same DC testing program) will be conducted to increase the electrical stress level (matching that of operational lines).

Overvoltage tests for switching and lightning on the ILCMS DC device did not reveal any critical issues for the tested equipment, and based on these results, it is deemed feasible to proceed with the planned field installation of the device on the HVDC 200 kV SA.CO.I line.