Grid Integration and Power Quality - Wind Energy Systems for Electric Power Generation - page 161

and up to the value corresponding to 95% of rated power. From the recorded data
are determined:

- the A-weighted sound power level,
- the sound composition in form of third-spectrum,
- a tonal increment K T in case of single tones,
- an impulse increment K I in case of impulse containing sound.
Statistical values as a function of rated generator power are shown in Fig. 7.18.
Typically, the sound power level produced by a wind generator system is determined
L WA ≈ 103 dB(A), taking tonal and impulse increments into account.

The sound pressure level in the vicinity of wind parks depends, besides the wind
velocity, on the systems types, the number of turbines and the location characteris-
tics.
Examples of measured sound power levels of WES of different rating are shown
in Fig. 7.19. An average of 103 dB(A) is typical for many systems at rated operation.
Curves of equal sound pressure level are illustrated around a single system, and
a wind park of 7 WES in Fig.7.20, respectively. The hub heights were 80 m, the
measurements taken at a height of 5 m.
Noise has become a crucial issue in regional and local procedures of plan-
ning and licensing new wind parks. Established limiting values are considered by

Fig. 7.18 Measured sound vs. wind velocity