Innovative noise reduction: Leitwind uses acoustic camera to localize noise sources
For about a year now, Leitwind has been using an acoustic camera to precisely locate the major noise sources of its wind turbines in an effort to eliminate, or at least reduce it as much as possible. This advanced testing technique makes it possible to display the results on a color emission map, which represents an “acoustic image” showing the part of each frequency that emits the most noise.
The acoustic camera (Picture 1) consists of a video camera and a series of microphones distributed over so-called “acoustic antennas”: the larger the diameter of these antennas, the higher the resolution of the emission map and the range of frequencies analyzed.
Picture 1: View of the Wind Turbine from the perspective of the acoustic camera
Put simply, the acoustic camera works in a similar way to the human ear: its origin can be identified based on the delay with which a sound or noise reaches the ear. In the acoustic camera, this process is carried out by 112 MEMS microphones. By time-shifting and recombining the signals using a special algorithm (“Sum and Delay”), the main sound source of the noise can be identified. Based on this information, an emission map is created that localizes the origin of the noise in terms of both time and frequency.
The technique used is non-invasive: in practice, the analyzed object, in this case the wind turbine, is examined in order to localize the specific sources of noise. This takes place in a very short time and the wind turbine is not disturbed during its operation process. The measurement takes a maximum of 10 seconds, and the results are available almost in real time. During data acquisition, the wind turbine (WTG) continues to operate and produce electricity. During testing, key operating parameters are monitored over time and videos being are acquired on specific intervals of particular interest.
This technology, which until a few years ago was used exclusively in industry (particularly in the automotive industry), is now also finding success in the environmental sector, such as wind power. The acoustic camera can also be used to determine whether the recorded noise actually comes from the wind turbines or whether it is caused by an external source.
Thanks to the synergies of the HTI Group and our shared production philosophy, we have advanced technological tools and specific technical expertise that enable us to improve the efficiency and performance of our various products in terms of noise reduction, once again underlining the company's commitment to innovative environmental technologies and increasingly sustainable solutions.