The expansion of renewable energy usage is one of the major social tasks in Europe and therefore requires acceptance and support from the population. In the case of onshore wind turbines, the complaints of local residents are often interpreted as infrasound disturbances conceivably caused by wind turbine operation. To improve the acceptance for wind energy projects, national standards and regulations need to incorporate such low frequency effects. This contribution presents long-term acoustic measurement data of low frequency noise recorded directly near wind turbines (emission) and inside of residential buildings (immission) with the objectives to identify the signal characteristics and main influential parameters. Different locations (wind farm and individual turbine), wind conditions, and time ranges are evaluated. It is shown that various frequency content below 150 Hz (harmonics of blade passing frequency, etc.) is connected to the rotation of the rotor blade and the operation of the generator. Furthermore, stable atmospheric conditions are determined to be of high importance for the transmission of the characteristic signals. For future research, this work also serves as an example for low frequency sound pressure data during operation and shutdown of wind turbines.

No abstract

In this paper, the influence of wind turbine operation conditions, like rotational speed, nacelle position and output power, on the low- and infrasonic sound emissions at the wind farm and sound immissions at residential buildings will be investigated. For this purpose, parallel measurements were carried out at a wind farm on the Swabian Alb in complex terrain and at four residential locations in the vicinity of the wind farm over a period of two months. Distinctive tones can be assigned to the blade passage at different rotational speeds. Furthermore, tones at 28.9 Hz (rated) and 18.3 Hz (below rated) with two higher harmonics can be attributed to the wind turbine generator. Wind farm infrasonic tones at the blade passing frequency were detected at the wind farm and residential buildings. At the residential buildings infrasonic tones were detected mainly for maximum rotational speed of the wind turbines and seem to be independent from wind direction.

No abstract

No abstract