Assessment of the Noise Generated by Wind Turbines at Low Frequencies

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Martino Marini ◽  
Roberto Baccoli ◽  
Costantino C. Mastino ◽  
Antonino Di Bella ◽  
Carlo Bernardini ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Low Frequency ◽  
Frequency Noise ◽  
Computational Tools ◽  
Low Frequencies ◽  
Special Concern ◽  
Assessment Procedures ◽  
The Impact ◽  
Noise Production

The noise production from wind turbines (WT) and its propagation into the surrounding environment have an impact on the receptors (RC) that have to be accurately predicted within the environmental impact assessment. The low-frequency noise (LFN) is of special concern for it is typical of wind systems and it involves specific computational issues. The purpose of this study is to apply and compare the assessment procedures currently used in different European countries for the prediction of LFN produced by wind turbines, with reference to a specific case. The results of the calculations for a planned wind farm in northern Sardinia, Italy, obtained by the available computational tools and with the help of the presented predictive models are presented and discussed. It can be deduced from this that the impact due to the low frequencies noise generated by wind turbines in the vicinity of sensitive receptors is negligible in terms of generated sound pressure levels (SPLs), even though further investigations on such a topic are needed.

Noise induced hearing loss in low frequencies in employees in a hospital microbiology department

2021 ◽  
Vol 7 (5) ◽  
pp. 861
Author(s):  
Konstantina Chrysouli ◽  
Dimitrios Kikidis
Keyword(s):  
Hearing Loss ◽  
Low Frequency ◽  
Control Group ◽  
Frequency Noise ◽  
Noise Induced Hearing Loss ◽  
Low Frequency Noise ◽  
Low Frequencies ◽  
History Of ◽  
Laboratory Workers ◽  
The Impact

<p class="abstract">Noise induced hearing loss (NIHL) is regarded as a serious problem and one of the most recorded occupational disorders in Europe and in the rest of the world and amounts to between 7% and 21% of the hearing loss. Aim of this study is to explore the development and the prevalence of low frequency noise-induced hearing loss (NIHL) in a hospital, especially in microbiology laboratory workers. Generally it is known that 4 KHz is the main NIHL frequency. Despite current theories, our study suggests for the first time the impact of low frequency noise in hearing loss among laboratory workers. According to the results, the population examined, namely the employees at the Microbiology Department of the Hospital, showed lower hearing levels compared to the control group, who had no history of occupational exposure to noise. There are many other studies which suggest that prolonged exposures to high noise levels have negative physiological and psychological effects on workers. The finding of the correlation of noise frequency with the frequency of the generated hearing loss is involved in the controversy about the pathophysiology of noise effect.</p>

scholarly journals Investigations on Low Frequency Noises of On-Shore Wind Turbines

Acoustics ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 343-367
Author(s):  
Esther Blumendeller ◽  
Ivo Kimmig ◽  
Gerhard Huber ◽  
Philipp Rettler ◽  
Po Wen Cheng
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Residential Buildings ◽  
Measurement Data ◽  
Low Frequency ◽  
National Standards ◽  
Future Research ◽  
Frequency Noise ◽  
Atmospheric Conditions ◽  
Social Tasks

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.

Ceiling Construction Low-Frequency Noise Issues

2013 ◽  
Vol 649 ◽  
pp. 277-280
Author(s):  
Petra Berková ◽  
Pavel Berka
Keyword(s):  
Spectral Analysis ◽  
Low Frequency ◽  
Sound Insulation ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Frequency Tone ◽  
The Impact ◽  
40 Hz

Through the use of a spectral analysis of the source of noise – person’s movement over the ceiling construction – it was found out that in this kind of noise distinctive low-frequency tone components occur (31,5 - 40 Hz) which is beyond the evaluation area of the impact sound insulation of the ceiling construction, s. [2], [3].

Low Frequency Noise Annoyance Assessment by Low Frequency Noise Rating (LFNR) Curves

1983 ◽  
Vol 2 (1) ◽  
pp. 20-28 ◽  
Author(s):  
N. Broner ◽  
H.G. Leventhall
Keyword(s):  
Laboratory Experiments ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Low Frequencies ◽  
Noise Annoyance

Over recent years, it has become apparent that low frequency noise annoyance is more widespread than originally believed. Annoyance has occurred where the emitted noise is unbalanced towards the low frequencies even though the dB(A) level has been low. Following laboratory experiments carried out as part of an investigation into low frequency annoyance, combined with field annoyance data, the Low Frequency Noise Rating (LFNR) curves are proposed for the assessment of low frequency noise annoyance complaints.

scholarly journals Making maps of cosmic microwave background polarization for B-mode studies: the POLARBEAR example

2017 ◽  
Vol 600 ◽  
pp. A60 ◽  
Author(s):  
Davide Poletti ◽  
Giulio Fabbian ◽  
Maude Le Jeune ◽  
Julien Peloton ◽  
Kam Arnold ◽  
...  
Keyword(s):  
Cosmic Microwave Background ◽  
Time Domain ◽  
Power Spectra ◽  
Low Frequency ◽  
Frequency Noise ◽  
Spectrum Estimation ◽  
Microwave Background ◽  
Polarization Studies ◽  
Ordered Data ◽  
The Impact

Analysis of cosmic microwave background (CMB) datasets typically requires some filtering of the raw time-ordered data. For instance, in the context of ground-based observations, filtering is frequently used to minimize the impact of low frequency noise, atmospheric contributions and/or scan synchronous signals on the resulting maps. In this work we have explicitly constructed a general filtering operator, which can unambiguously remove any set of unwanted modes in the data, and then amend the map-making procedure in order to incorporate and correct for it. We show that such an approach is mathematically equivalent to the solution of a problem in which the sky signal and unwanted modes are estimated simultaneously and the latter are marginalized over. We investigated the conditions under which this amended map-making procedure can render an unbiased estimate of the sky signal in realistic circumstances. We then discuss the potential implications of these observations on the choice of map-making and power spectrum estimation approaches in the context of B-mode polarization studies. Specifically, we have studied the effects of time-domain filtering on the noise correlation structure in the map domain, as well as impact it may haveon the performance of the popular pseudo-spectrum estimators. We conclude that although maps produced by the proposed estimators arguably provide the most faithful representation of the sky possible given the data, they may not straightforwardly lead to the best constraints on the power spectra of the underlying sky signal and special care may need to be taken to ensure this is the case. By contrast, simplified map-makers which do not explicitly correct for time-domain filtering, but leave it to subsequent steps in the data analysis, may perform equally well and be easier and faster to implement. We focused on polarization-sensitive measurements targeting the B-mode component of the CMB signal and apply the proposed methods to realistic simulations based on characteristics of an actual CMB polarization experiment, POLARBEAR. Our analysis and conclusions are however more generally applicable.

scholarly journals Prediction of noise from wind turbines: theoretical and experimental study

2018 ◽  
pp. 34-41 ◽  
Author(s):  
Carlos Alberto Echeverri-Londoño ◽  
Alice Elizabeth González Fernández
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Sound Pressure ◽  
Prediction Method ◽  
Wide Band ◽  
Propagation Models ◽  
Low Frequencies ◽  
High Frequencies ◽  
Wind Speeds ◽  
Sound Pressure Levels

Several noise propagation models used to calculate the noise produced by wind turbines have been reported. However, these models do not accurately predict sound pressure levels. Most of them have been developed to estimate the noise produced by industries, in which wind speeds are less than 5 m/s, and conditions favor its spread. To date, very few models can be applied to evaluate the propagation of sound from wind turbines and most of these yield inaccurate results. This study presents a comparison between noise levels that were estimated using the prediction method established in ISO 9613 Part 2 and measured levels of noise from wind turbines that are part of a wind farm currently in operation. Differences of up to 56.5 dBZ, with a median of 29.6 dBZ, were found between the estimated sound pressure levels and measured levels. The residual sound pressure levels given by standard ISO 9613 Part 2 for the wind turbines is larger for high frequencies than those for low frequencies. When the wide band equivalent continuous sound pressure level is expressed in dBA, the residual varies between −4.4 dBA and 37.7 dBA, with a median of 20.5 dBA.

scholarly journals Impedance Aggregation Method of Multiple Wind Turbines and Accuracy Analysis

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2035 ◽  
Author(s):  
Liang Chen ◽  
Heng Nian ◽  
Yunyang Xu
Keyword(s):  
Stability Analysis ◽  
Reference Frame ◽  
Wind Turbines ◽  
Power Distribution ◽  
Wind Farm ◽  
System Level ◽  
Small Signal ◽  
Impedance Model ◽  
The Stability ◽  
The Impact

The sequence domain impedance modeling of wind turbines (WTs) has been widely used in the stability analysis between WTs and weak grids with high line impedance. An aggregated impedance model of the wind farm is required in the system-level analysis. However, directly aggregating WT small-signal impedance models will lead to an inaccurate aggregated impedance model due to the mismatch of reference frame definitions among different WT subsystems, which may lead to inaccuracy in the stability analysis. In this paper, we analyze the impacts of the reference frame mismatch between a local small-signal impedance model and a global one on the accuracy of aggregated impedance and the accuracy of impedance-based stability analysis. The results revealed that the impact is related to the power distribution of the studied network. It was found that that the influence of mismatch on stability analysis became subtle when subsystems were balanced loaded. Considering that balanced loading is a common configuration of the practical application, direct impedance aggregation by local small-signal models can be applied due to its acceptable accuracy.

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