This report describes the experimental activities, both laboratory and field campaign, carried out during 2023 on the surface contamination of insulators in order to support the modeling reconstruction of this phenomenon.

In the study on the phase changes of the deposition on insulators using a controlled chamber (Aerosol Exposure Chamber, AEC), preliminary analyzes of the effects of a water-repellent coating were conducted. The tests confirmed a difference in behavior between the two types of coating, but further investigation is required to verify their effects on conductivity.

Experimental field activities aimed at characterizing the quantity and chemical composition of the deposit on the insulators throughout 2023 continued in the RSE experimental structure called ContIsola. These activities allow the reconstruction of historical contamination levels at a site of interest and the exploration of suitable experimental methodologies to monitor insulator contamination.

The new measurement campaign began in April 2023, covering 67 national sites and one coastal site. At the coastal site, in addition to standardized characterization of the deposit through conductivity, and ESDD and NSDD measurements, meteorological monitoring is carried out. Short-term intensive campaigns are also carried out to chemically characterize the deposit on the insulators surface, and the total suspended atmospheric aerosol (TSP) both on the ground and at altitude.

Initial evaluation of the analyzes conducted on the TSP samples collected in 2023 did not reveal significant differences between the samples collected at altitude and those on the ground. This suggests that, at least in the first hypothesis, ground-level concentrations can be considered sufficiently representative also at the height of the insulators.

Regarding the role of the different emission sources, it was observed that the major contribution is associated with long-range transport of sea spray.

Morphological and chemical analyzes of contaminants taken from the insulators seem to confirm the assessments on the sources of the atmospheric aerosol. Predominant presence of Na, S, Cl and Ca is mainly derived from sea salt particles, followed by calcium sulphate.

The document is available on the site in Italian