Study of ice accretion feature and power characteristics of wind turbines at natural icing environment

Wide cold regions with high air density as well as wind speed are much beneficial for the wind energy exploitation. However, wind turbines in these regions always suffer a series of icing issues, especially the blade aerodynamics degradation and much production loss in winter. Therefore, the paper aims to study the ice accretion feature on blades and the effect of ice severity on the power performance of wind turbines at natural icing environment. The ice distribution on the blade is analyzed quantitatively in the image processing method, and it is found that the ice thickness on the blade increases rapidly from the root to the middle of the blade, and then slowly from the middle to the blade tip. In the icing duration period, both the pitch angle and rotor speed of the wind turbine fall remarkably at the same wind speed, and the pitch angle shows more sensitive to the blade icing for wind turbines with the traditional control strategy. Based on the statistical operating data of the 300 kW wind turbine in different icing cases, the rotor performance deteriorates more seriously as the ice thickness of the blade increases, which changes the original matching relation between the rotor and generator. In addition, the ice thickness of the leading edge at r/R= 0.95 shows great correlation with power loss in given icing cases, and this correlation still needs to be studied further at more icing events. The results can provide a reference for the operation performance of wind turbines in cold regions.