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Author:Lehto, Panu
Title:Signal analysis of wind turbine acoustic noise
Tuuliturbiinin akustisen melun signaalianalyysi
Publication type:Master's thesis
Publication year:2014
Pages:80      Language:   eng
Department/School:Signaalinkäsittelyn ja akustiikan laitos
Main subject:Akustiikka ja äänenkäsittelytekniikka   (S-89)
Supervisor:Välimäki, Vesa
Instructor:Di Napoli, Carlo
Electronic version URL: http://urn.fi/URN:NBN:fi:aalto-201412303351
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  2760   | Archive
Keywords:acoustic noise
acoustic measurements
noise measurements
signal analysis
signal processing
narrowband
wind turbines
melu
akustinen mittaus
melun mittaus
signaalianalyysi
signaalinkäsittely
kapeakaistaisuus
tuuliturbiini
Abstract (eng):In Finland wind turbines are becoming more common.
Wind farms are built outside residential concentrations where wind conditions are strong enough for power production.
Even though the locations are remote, turbines are sometimes erected near dwellings and therefore the generated noise emissions have to meet certain threshold levels.

In order to ensure that the required noise levels do not exceed the limits, measurements have to be done.
The most recent standard for wind turbine noise analysis is IEC 61400-11.
In this thesis the tonal audibility of a turbine is assessed by the means of the standard.

The analysis method requires background noise to have a steady frequency dis- tribution of energy within a critical band.
Otherwise the calculations reveal sin- gle tones generating from the background noise.
Variation of frequency between consecutive 10 second sections of the acquired signal is allowed, which makes it possible for tones with questionable audibility to be reported
Abstract (fin):Tuuliturbiinien määrä lisääntyy Suomessa.
Tuulipuiston rakentamisen edellytyksinä ovat suotuisat tuuliolosuhteet ja tarpeeksi suuri vapaa alue.
Asutuskeskuksien ulkopuolella kuitenkin esiintyy yksittäisiä asuntoja, joiden takia turbiineista lähtevä melutaso ei saa ylittää määrättyjä raja-arvoja.

Turbiinin tuottaman melu mitataan, jotta voidaan varmistaa vaadittujen tasojen alitus.
Viimeisin standardi tuuliturbiinimelun analysoimiseksi on IEC 61400-11.
Tässä diplomityössä on määritelty turbiinin tuottama kapeakaistaisen melun kuuluvuus standardin avulla.

Taustamelun energian jakautuminen tasaisesti kriittisen kaistan leveydelle on edellytys laskennan onnistumiselle.
Jos vaihtelevuus taajuuspiikkien välillä on suurta analyysitapa löytää ääneksiä taustamelusta.
Laskentamalli sallii yksittäisen ääneksen taajuusvaihtelun 10 sekunnin pituisten näytteiden välillä.
Tämä mahdollistaa kapeakaistaisuuden löytymisen, vaikka sen kuuluvuudesta ei ole varmuutta.
ED:2015-04-27
INSSI record number: 51123
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