Ice and snow accumulation poses a significant threat to the reliability of the electrical system. For Italian transmission and distribution system the main issue is represented by wet snowfall events, occurring at temperatures close to 0°C, with snow density reaching up to 350 Kg/m3. Ice-phobic and snow-phobic coatings are one of the most promising ways for hindering ice and snow accumulation.

A large number of studies report of icing and freezing phenomena and many methods have been developed over time to assess ice-phobic performances of coatings, mainly measuring ice adhesion (eg. shear stress testing, centrifuge testing etc.) and freezing delay. Many mechanisms have been consequently proposed to explain ice-phobic properties of tested coatings, according to their chemical composition and mechanical properties.

On the other hand, snow offers a considerable complexity and factors such as crystal structure, density, and liquid water content (LWC) can vary sharply with weather conditions. These properties have significant implications on the adhesion of snow on surfaces and inferring snow-phobicity of coatings from their ice-phobic performances can be misleading. For practical reasons it is somehow difficult to deal with snow for indoor performance testing and the tests are commonly delegated to outdoor activities. Outdoor testing of coatings is however affected by external uncontrollable factors such as the occurrence of snowfall events and their intensity, the presence of wind, air humidity and the presence of condensed water on surfaces.

To overcome these problems and to achieve a stricter measurement of the snow-phobic properties of coatings, RSE has recently put into operation the first artificial snow laboratory in Italy. This facility is capable of simulating snowfall with controllable flow, reaching a coverage up to about 10 cm×m-2×h-1, and to produce both dry and wet snow, with LWC ranging from about 3% to 35%. The snow production is performed inside a cold chamber with settable air flow and temperature, down to -10°C, and measured relative humidity.

For the testing of snow-phobic coatings deposed on segments of conductors and ground wires, the laboratory is equipped with a custom-made apparatus capable of slowly rotating them, allowing the growth of artificial snow sleeves. The process, reproducing the sleeve accretion on OHL, is monitored through a camera and quantified with load cells that record the weight of the accumulated snow over time. It is thus possible to measure the snow-phobic behavior of coatings, in terms of delaying the formation of the snow sleeve and/or facilitating an earlier detachment. The laboratory is also equipped with a universal tensile strength machine to develop shear stress test with snow on flat surfaces.

All depicted tests can be performed with varying snow properties and environmental conditions of cold chamber, to assess the performances of coatings under different simulated snowfall scenarios.

The artificial snow laboratory is thus a valuable tool for the measurement of snow-phobic properties of surfaces and for a deeper comprehension of adhesion and detachment mechanisms, helping to provide valuable hints for further research and development.