Long term wind turbine sound monitoring

Abstract

In the DLR Windpark WiValdi, consisting of two wind turbines, extensive measurements of sound and meteorology have been conducted. In the context of long-term wind turbine sound monitoring, the data from such measurements are used to understand and decipher physical effects of sound propagation. This kind of data suffers sometimes for reliability, because of many changing conditions and situations around the microphone. Therefore, in three different phases the sound of various sources were captured. Before the turbines were installed, initial measurements were made to identify background noise, followed by additional measurements to assess the impact of new installed weather masts on the sound field. Ultimately, the exact state (such as rotation speed, pitch, yaw, etc.) of the wind turbines shall be reported, to relate weather and operational conditions to the associated sound levels. This presentation illustrates how all these measurements are used to create a consistent picture of the noise situation around the wind park depending on specific weather situation and discusses the need of accuracy. We document the limitations and uncertainties associated with the measurements and show these limitations when interpreting and reporting the results to ensure users in understanding the reliability and confidence level of such data.