The effect of icing severity on wind turbine ice protection systems efficiency

In the past years, there has been a gain of interest in wind turbine Ice Protection Systems (IPS) as wind farm owners realize the extent of their ice-induced losses. More and more wind turbine manufacturers are now offering IPSs in their cold climate packages. IPS retrofits are now available to minimize icing losses on existing unheated wind turbines. With this growth in interest, questions about the efficiency of those systems arise. Field experience has shown that these systems can be ineffective in certain ambient conditions which led to the concept of IPS performance envelopes. These envelopes lay out on a wind speed vs ambient temperature map the conditions where IPSs are expected to be effective. While these envelopes can give a good overlook of the IPSs efficiency in post-icing conditions, they neglect the effect that icing severity can have on IPS effectiveness. This paper presents a simple 1D model for hot-air IPS able to generate performance envelopes considering the icing severity. This model was validated with the production data of six different icing events. It has been shown to be coherent with the observed efficiency of the hot air IPS.