Design Procedures and Experimental Verification of an Electro-Thermal De-Icing System for Wind Turbines

Abstract. Electro-thermal heating is one of the main technologies used to protect rotors from ice accretion and it is one of the main technologies being considered to protect wind turbines. The design process required to develop an ice protection system for wind turbines is detailed. Three icing conditions were considered: Light, Medium and Severe. Light icing conditions were created using clouds at −8 °C with a 0.2 g/m³ liquid water content (LWC) and water droplets of 20 µm median volumetric diameter (MVD). Medium icing condition clouds had a LWC of 0.4 g/m³ and 20 μm MVD, also at −8 °C. Severe icing conditions had an LWC of 0.9 g/m³ and 35 μm MVD at −8 °C. Wind turbine representative airfoils protected with electro-thermal de-icing were modeled and tested at representative centrifugal loads and flow speeds. The wind turbine sections used were 1/2 scale models of the 80 % span region of a generic 1.5 MW wind turbine blade. Based on experimental and modeling efforts, de-icing a representative 1.5 MW wind turbine with a 100 kW power allocation required four sections along the span, with each heater section covering 17.8 % span and delivering a 2.48 W/in² (0.385 W/cm²) power density. The time sequences for the controller required approximately 10 minutes for each cycle.