Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In this work we perform a statistical analysis of global solar radiation measured at two sites, 38 km distant from, in Guadeloupe, French West Indies. We have established a correlation model based on the coefficient of variation assuming a time scale separation. The coefficient of variation is calculated on minutes interval with data measured at 1 Hz. This analysis highlight the dynamic correlation that can occur between measurements from two different sites with a time step of one second. From this results, knowing the coefficient of variation on a site we have established a new correlation model on this parameter for another site. A diagram linking the standard deviation on both sites, for a given coefficient of variation is proposed for correlated and non-correlated cases. More over this analysis put in evidence the existence of a threshold time under which there is no significant correlation. This model can be useful in choosing new sites of production not only for establishing correlation from on site to another, but also in optimizing the geographical distribution of the solar farms within the territory.
ISSN: 0960-1481

Droits : http://hal.archives-ouvertes.fr/licences/copyright/
hal-01099045
https://hal.archives-ouvertes.fr/hal-01099045
https://hal.archives-ouvertes.fr/hal-01099045/document
https://hal.archives-ouvertes.fr/hal-01099045/file/Article%20Foison_2014.pdf

Éditeur(s) : HAL CCSD
Résumé : Un dispositif expérimental a été élaboré pour effectuer l'étude systématique d'un écoulement d'air en convection naturelle dans un canal plan ouvert. Les conditions aux limites imposent une densité de flux uniforme sur une paroi, la paroi en vis-à-vis est chauffée par rayonnement de la première. L'étude s'intéresse à l'influence du nombre de Rayleigh et du rapport d'allongement du canal sur l'apparition d'une alimentation du thermosiphon par la section de sortie.Cet écoulement inverse est visualisé par tomographie laser et quantifié par des profils de vitesse mesurés par vélocimétrie laser.
Actes de la SFT 2008
TOULOUSE, France

hal-00292639
https://hal.archives-ouvertes.fr/hal-00292639

Éditeur(s) : HAL CCSD
Résumé : International audience
Proceedings of IEEE Power Engineering Society General Meeting, 2007.

hal-00692555
https://hal.archives-ouvertes.fr/hal-00692555

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
The Taylor power law (or temporal fluctuation scaling), is a scaling relationship of the form σ ~ (P)λ where !! is the standard deviation and hPi the mean value of a sample of a time series has been observed for power output data sampled at 5 min and 1 s and from five wind farms and a single wind turbine, located at different places. Furthermore, an analogy with the turbulence field is performed, consequently allowing the establishment of a scaling relationship between the turbulent production IP and the mean value (P)
ISSN: 2079-9276

hal-01528077
https://hal.archives-ouvertes.fr/hal-01528077
https://hal.archives-ouvertes.fr/hal-01528077/document
https://hal.archives-ouvertes.fr/hal-01528077/file/resources-04-00787.pdf
DOI : 10.3390/resources4040787

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Wind energy production is very sensitive to turbulent wind speed. Thus rapid variation of wind speed due to changes in the local meteorological conditions can lead to electrical power variations of the order of the nominal power output, in particular when wind power variations on very short time scales, range at few seconds to 1 h, are considered. In small grid as they exist on islands (Guadeloupean Archipelago: French West Indies) such fluctuations can cause instabilities in case of intermediate power shortages. The developed analysis in [14] reveals three main classes of time series for the wind speed fluctuations. In this work, Probability Density Functions (PDFs) are proposed to fit the wind speed fluctuations distributions in each class. After, to simulate wind speed fluctuations sequences, we use a stochastic differential equation, the Langevin equation considering Gaussian turbulence PDF (class I), Gram–Charlier PDF (class II) and a mixture of gaussian PDF (class III). The statistical and dynamical properties of simulated wind sequences are close to those of measured wind sequences, for each class
ISSN: 0306-2619

hal-01527885
https://hal.archives-ouvertes.fr/hal-01527885
DOI : 10.1016/j.apenergy.2012.05.007

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Wind energy production is very sensitive to instantaneous wind speed fluctuations. Thus rapid variation of wind speed due to changes in the local meteorological conditions can lead to electrical power variations of the order of the nominal power output. The high variability of this renewable energy source can caused a disruptive effect on power quality and reliability, in non-interconnected island networks as in Guadeloupe (French West Indies). To palliate these difficulties, it is essential to identify and characterize the wind speed distribution over very short time intervals. This allows anticipating the eventuality of power shortage or power surge. Therefore, it is of interest to categorize wind speed fluctuations into distinct classes and to estimate the probability of a distribution to belong to a class. This paper presents a method for classifying wind speed distributions by estimating a finite mixture of Dirichlet distributions. The SAEM algorithm that we use provides a fine distinction between three wind speed distribution classes. It is a new nonparametric method for wind speed classification.
ISSN: 0960-1481

hal-01527881
https://hal.archives-ouvertes.fr/hal-01527881
DOI : 10.1016/j.renene.2011.03.024

Éditeur(s) : HAL CCSD Intech
Résumé : International audience
The massive integration of sustainable energies into electrical grids (non-interconnectedor connected) is a major problem due to their stochastic character revealed by strongfluctuations at all scales. In this paper, the scaling behaviour or power law correlationsand the nature of scaling behaviour of sustainable resource data such as flow velocity,atmospheric wind speed, solar global solar radiation and sustainable energy such as,wind power output, are highlighted. For the first time, Fourier power spectral densitiesare estimated for each dataset. We show that the power spectrum densities obtained areclose to the 5/3 Kolmogorov spectrum. Furthermore, the multifractal and intermittentproperties of sustainable resource and energy data have been revealed by the concavityof the scaling exponent function. The proposed analysis frame allows a full descriptionof fluctuations of processes considered. A good knowledge of the dynamic of fluctua-tions is crucial to management of the integration of sustainable energies into a grid.
Sustainable Energy - Technological Issues, Applications and Case Studies

hal-01528087
https://hal.archives-ouvertes.fr/hal-01528087
DOI : 10.5772/106341

Éditeur(s) : Séminaire CLAROM, 14èmes journées de l'Hydrodynamique, Val de Reuil, 18-20 novembre 2014
Résumé : From measurements obtained at high level frequency over a long period of time, we aim to determine the different characteristics of the flow situated in the IFREMER (French Research Institute for Exploration of the Sea) wave and current flume tank in Boulogne-Sur-Mer. This 2 data measured with a LDV (Laser Doppler Velocimetry) allows to get the characteristics of turbulence and the incident velocity fluctuations. The well-controlled conditions in the flume and the high sampling frequency of LDV system will give us a good estimate of the different flow characteristics such as dissipation, the Reynolds number, the injection scales, Taylor and Kolmogorov. The objective is to place the marine current turbine in this flow and then to study the influence of turbulence on the rotor of this turbine. The flow velocity is imposed and two different rates of turbulence are analysed.
A partir de données à haute fréquence acquises pendant une longue période de temps, on cherche à déterminer les différentes caractéristiques de l’écoulement généré au bassin d’essais à houle et courant d’IFREMER à Boulogne-Sur-Mer. Ces données mesurées avec un système LDV permettent de caractériser la turbulence et les fluctuations de la vitesse du courant incident. Les conditions contrôlées du bassin et les longues périodes d’acquisition du système LDV nous donneront une bonne estimation des différentes caractéristiques de l’écoulement tels que la dissipation, le nombre de Reynolds, les échelles d’injection, de Taylor et de Kolmogorov. Dans un deuxième temps nous étudions les effets de la turbulence de l’écoulement sur le comportement d’une hydrolienne tri-pale à axe horizontal.L’objectif est de placer la maquette d’hydrolienne dans cet écoulement et étudier l’influence de la turbulence sur le rotor de cette turbine. La vitesse de l’écoulement est imposée et deux taux de turbulence différents ont été étudiés.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00247/35814/34329.pdf
http://archimer.ifremer.fr/doc/00247/35814/

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
Wind energy production is very sensitive to turbulent wind, in particular when wind power variations range from few seconds to 1 hour, are considered. Indeed rapid changes in the local meteorological condition as observed in tropical climate can provoke large variations of wind speed. Consequently the electric grid security can be jeopardized due to these fluctuations. This is particularly the case of island networks as in the Guadeloupean archipelago (French West Indies) where the installed 20 MW wind power already represents 11% of the electrical consumption. From 1 million wind sequences of duration 10 minutes, sampled at 1 Hz during the trade season, we proceed toward two objectives: i) the characterization of the wind speed sequences, ii) the dynamical simulation of the wind sequences using Langevin equation.
Progress in Turbulence and Wind Energy IV

ISBN : 978-3-642-28968-2.
hal-01527883
https://hal.archives-ouvertes.fr/hal-01527883
DOI : 10.1007/978-3-642-28968-2-50

Éditeur(s) : HAL CCSD Institut Henri Poincaré-Nonlinéaire Publications
Résumé : International audience
Depuis quelques décennies, l'énergie éolienne connaît une croissance considérable. Cependant cette énergie est dépendante de la vitesse du vent variant en intensité sur des échelles de temps qui incluent l'année, la journée à quelques secondes. Il est donc fondamental de bien parvenir à comprendre et décrire le caractère non-linéaire et stochastique de ces fluctuations dans la production électrique issue des éoliennes. L'objectif de ce travail est de caract'eriser les fluctuations d'une série temporelle de production éolienne. Dans un premier temps, nous vérifions l'utilisation de la loi de Taylor, relation de puissance entre l'écart-type et la moyenne. Cette relation fut observée en écologie, en finance, dans les sciences du vivant et pour des données de traffic internet. De récents travaux fournissent des hypothèses d'explication quant à l'origine de cette loi cite{Agata2010,Kendall2011}. L'exposant alpha caractérise le type de dynamique du processus considéré et varie entre 1/2 et 1. Dans notre cas d'étude, l'estimation de l'exposant alpha est proche de 1. Quand alpha=1, les processus considérés sont à invariance d'échelle cite{eisler2008}. Pour mettre en évidence les propriétés d'invariance d'échelle de notre série temporelle, nous effectuons une analyse multifractale pour estimer la fonction exposant d' échelle l'aide des moments d'ordre $q$ de l'incrément temporel des données de production éolienne $Delta P=P(t+ au)-P(t)$, telle que $<(Delta P_ au)^q>simeq au^{zeta(q)}$ cite{Schertzer1997}. La fonction $zeta(q)$ est concave et non-linéaire: plus elle est concave, plus la série analysée sera intermittente. Nous montrons que la série temporelle de la production éolienne considérée est intermittente et possède des propriiétés multifractales. De plus le modèle de cascades aléatoires log-normal se révèle pertinent pour décrire ces fluctuations.
Compte-rendus de la 15ème Rencontre du non-linéaire

hal-01527884
https://hal.archives-ouvertes.fr/hal-01527884

Éditeur(s) : HAL CCSD
Résumé : International audience
CONGRES FRANÇAIS DE THERMIQUE
TOULOUSE, France

hal-00394069
https://hal.archives-ouvertes.fr/hal-00394069

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The correlation between the flow turbulence and the performances of a ma- rine current turbine is studied. First, the incoming flow encountered in the flume tank is characterized in the framework of fully developed turbulent cascades in the inertial range. The Reynolds number, the Kolmogorov dissipation scale and the integral scale, are estimated from flow measurements. The intermittency of the turbulence is characterized in the lognormal multifractal framework, and the influence of the turbulent flow on the turbine power is assessed. The rotor speed control unit characteristics used for the turbine regulation induces non-negligible effects on the turbine behavior under fluctuations loads. Even if the power spectrum does not reveal any scale invariance, a multiscale analysis allows us to show the correlations between the turbulence time se- ries and the power produced. The classical Mean Square Coherency function shows that for scales larger than 10 seconds, the upstream velocity and power have large correlations. In the framework of the Empirical Mode Decomposition method, such correlations are studied using the time-dependence intrinsic corre- lation analysis method. This method allows to zoom into time-frequency scales where the flow perturbations induced some modifications in power production
ISSN: 0960-1481

hal-01528296
https://hal.archives-ouvertes.fr/hal-01528296
DOI : 10.1016/j.renene.2017.05.024

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The objectives are to study and model the aggregate wind power fluctuations dynamics in the multifractal framework. We present here the analysis of aggregate power output sampled at 1 Hz during three years. We decompose the data into several Intrinsic Mode Functions (IMF) using Empirical Mode Decomposition (EMD). We use a new approach, arbitrary order Hilbert spectral analysis, a combination of EMD approach with Hilbert spectral analysis (or Hilbert Huang Transform) and the classical structure function analysis to extract the scaling exponents or multifractal spectrum $zeta(q)$: this function provides a full characterization of a process at all intensities and all scales. The application of both methods, i.e. structure function and arbitrary-order Hilbert spectral analyses, give similar results indicating that the aggregate power output from a wind farm, possesses intermittent and multifractal properties. In order to check this result, we generate stochastic simulations of a Multifractal Random Walk (MRW) using a log-normal stochastic equation. We show that the simulation results are fully compatible with the experimental results.
Physica A

hal-01527887
https://hal.archives-ouvertes.fr/hal-01527887
DOI : 10.1016/j.physa.2013.04.038

Éditeur(s) : HAL CCSD
Résumé : International audience
There is growing efforts for the development of wind energy. Yet, as for other renewable resources, a basic characteristic of wind energy is to deliver intermittent power. In this paper, we consider this topic by analyzing data provided by the wind industry. We discuss first the spectral properties of the data and the corresponding power curve. We estimate the scaling behavior in the inertial scale of wind input and the power output. We also study the rotor revolution scaling fluctuations. Finally the wind/power transfer function is studied, together with the wind/rotation and rotation/power intermediary transfer functions.
Energy Procedia

hal-01273262
https://hal.archives-ouvertes.fr/hal-01273262
DOI : 10.1016/j.egypro.2015.07.897

Éditeur(s) : HAL CCSD
Résumé : International audience
Journal of Applied Nonlinear Dynamics

hal-01528080
https://hal.archives-ouvertes.fr/hal-01528080
DOI : 10.5890/JAND.2016.12.001

Éditeur(s) : HAL CCSD Springer
Résumé : In this work, we present an analysis of one-year period measured wind speed in the atmospheric boundary layer from a wind energy production site. We employ a Hilbert-based methodology, namely arbitrary-order Hilbert spectral analysis to characterize the intermittent property of the wind speed in a joint amplitudefrequency space. The measured scaling exponents implies intermittent nature of the wind on mesoscales.
Wind Energy: Impact of Turbulence

ISBN : 978-3642546952
hal-00958512
https://hal.archives-ouvertes.fr/hal-00958512

Éditeur(s) : HAL CCSD European Geosciences Union (EGU)
Résumé : International audience
We consider here wind speed time series and the aggregate output wind power from a wind farm. We study their scaling statistics in the framework of fully developed turbulence and Kolmogorov's theory. We estimate their Fourier power spectra and consider their scaling properties in the physical space. We show that the atmospheric wind speed and the aggregate power output from a wind farm are intermittent and multifractal over a wide range of scales. The coupling between simultaneous data of the wind speed and aggregate power output is investigated through a joint multifractal description using the generalized correlation functions (GCFs). This multiscaling test is compatible with a linear relation between the wind speed and the aggregate power output fluctuations for timescales T ⩾ 103 s ≃ 15 min
ISSN: 1023-5809

hal-01527893
https://hal.archives-ouvertes.fr/hal-01527893
DOI : 10.5194/npg-21-379-2014

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A good knowledge of the intermittency of global solar radiation is crucial for selecting the location of a solar power plant and predicting the generation of electricity. This paper presents a multifractal analysis study of 367 daily global solar radiation sequences measured with a sampling rate of 1 Hz over one year at Guadeloupean Archipelago (French West Indies) located at 16 150N latitude and 60 300W longitude. The mean power spectrum computed follows a power law behavior close to the Kolmogorov spectrum. The intermittent and multifractal properties of global solar radiation data are investigated using several methods. Under this basis, a characterization for each day using three multifractal parameters is proposed.
ISSN: 0038-092X

hal-00903410
https://hal.archives-ouvertes.fr/hal-00903410
DOI : 10.1016/j.solener.2013.09.018

Éditeur(s) : HAL CCSD
Résumé : Aricle soumis à Solar Energy
In order to qualify the fluctuating nature of solar radiation under tropical climate, we classify daily distributions of the clearness index kt by estimating a finite mixture of Dirichlet distributions without assuming any parametric hypothesis on these daily distributions. The method is applied to solar radiation measurements performed in Guadeloupe (16°2 N, 61 W) where important fluctuations can be observed even within a short period of a few minutes. The results put in evidence four distinct classes of distributions corresponding to different types of days. The sequence of such classes can be of interest for prediction.
https://hal.archives-ouvertes.fr/hal-00289567

hal-00289567
https://hal.archives-ouvertes.fr/hal-00289567
https://hal.archives-ouvertes.fr/hal-00289567/document
https://hal.archives-ouvertes.fr/hal-00289567/file/Article_Classif_soumis.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In this paper, we have presented a spectral and a multifractal analysis performed on 412 time series of wind speed data each of duration of 350 s and sampled at 20 Hz. The average spectrum for the wind speed displays a scaling behavior, in the inertial range, over two decades, with b ¼ 1:68 close to the Kolmogorov value À 5/3. A multifractal analysis has been motivated by the presence of scaling invariance in data set. Then we have considered their scaling properties in the framework of fully developed turbulence and multifractal cascades. The results obtained for wind speed confirm that the exponent scaling function z V ðqÞ is nonlinear and concave. This exponent characterizes the scaling functions in the inertial range indicating that the wind speed is intermittent and multifractal. Moreover the theoretical quadratic relation for lognormal multifractals is well fitted. We investigate the consequence for wind energy production: we generate stochastic simulations of a multifractal random walk, and using a power curve derived from experimental data, we generate the associated power time series. We show that, due to the saturation of the power curve for large speed values, when the input time series (turbulent wind speed) is multifractal, the output can be almost monofractal.
ISSN: 0167-6105

hal-01527886
https://hal.archives-ouvertes.fr/hal-01527886
DOI : 10.1016/j.jweia.2012.06.002