Evaluation of operational strategies on wind turbine power production during short icing events

Abstract

Cold climates around the world are seeing increasing investment in wind power generation. The benefits of cold regions, however, come with unique challenges such as the accumulation of ice on wind turbine blades, which impacts the aerodynamic properties of the blades and, in turn, power production. One decision that must be made when facing an icing event is whether to maintain operation of the turbine or to pause the rotor until the event has passed. Powering through an icing event allows the operator to maintain power production, but with an increase in ice accumulation and associated adverse effects. Pausing the wind turbine results in less ice accumulation and may therefore provide higher power production once operation is resumed. The aim of this research was to complete a comparative assessment of these two strategies with regards to overall impact on power production. A numerical Ice and Power Model was developed, validated, and employed to assess power production impacts on a 1.5 MW wind turbine for five 2-h icing events with varying atmospheric parameters. The simulation results on short icing events provide evidence that while pausing the turbines does indeed result in significantly less ice accumulation, the positive impact on power production compared to the power-through strategy is insufficient to justify the shut-down strategy. This is found to be due to the overpowering impact of surface roughness from ice crystal beading on blade aerodynamics, which occurs whether or not the blades are rotating.