Nacelle transfer function inconsistent over time

Understanding the nacelle transfer function inconsistent over time turbine issue check

What is the purpose of the turbine issue check?

• A given turbine has a nacelle transfer function that changes over time, either continuously, intermittently, or with discrete change points.

What does this look like?

• In this example, the nacelle transfer function changed in September 2020
• Turbine could be underperforming due to a mismatch between anemometer and nacelle transfer function