Forecasting and monitoring wet-snow sleeve on overhead power lines in Italy

Wet snow accretion on overhead power lines is a real problem in Italy, causing failures and several blackouts on HV and MV power lines during the winter season. To answer this harmful atmospheric phenomenon, RSE has developed a weather forecast system named WOLF -Wet snow Overload aLert and Forecasting- for the electric power grid warning. WOLF, together with wet snow load prediction, provides an estimation of the anti-icing current necessary to maintain lines free of snow sleeve formations, This information supports the TSO operators in adopting mitigation active strategies. In synergy with WOLF, an automatic station named WILD -Wet snow Ice Laboratory Detection- has been installed in the municipality of Vinadio in the west Alps, at an altitude of 950 m asl for the forecast system verification. Through innovative measurements, it is possible to analyse in detail the most critical weather conditions for the wet snow sleeve formation on conductors. WILD is the first station in Italy devoted to study the power lines behavior during wet snowfall events. The station is equipped with instruments with proven reliability in extreme weather conditions for monitoring wet snow loads and ice thickness on some samples of typical HV conductors. This experimental activity is the first step towards a real time monitoring system of sleeve accretion on operational overhead lines.