scholarly journals The Method for Risk Assessment of SSR Caused by Doubly-Fed Wind Farms

2018 ◽  
Vol 173 ◽  
pp. 01028
Author(s):  
Xiao Yu ◽  
Guofei Lu ◽  
Wuhui Chen ◽  
Danhui Wang
Keyword(s):  
Wind Speed ◽  
Wind Farm ◽  
Risk Index ◽  
Wind Farms ◽  
Series Compensation ◽  
Average Wind Speed ◽  
Average Wind ◽  
Doubly Fed ◽  
The Impact ◽  
Compensation Level

The existing method for investigating the subsynchronous resonance (SSR) caused by wind powergeneration is mainly aimed at a deterministic condition. In order to analyse the impact of uncertain factors onSSR in wind farms, this paper defines the risk matrix and risk index, and develops a SSR-oriented riskassessment method of using probabilistic collocation method (PCM). Considering the uncertain of windspeeds, the proposed method is used to assess the SSR risk of a wind farm. The results show that under thesame wind speed distribution, the higher the series compensation level in the system is, the greater the SSRrisk of the system could be; under the same series compensation level, the SSR risks caused by different windspeed distribution are different, and the system in the areas with lower average wind speed obtains greater SSR risk.

A simple gust estimation algorithm and machine learning based nowcasting for wind turbines

2020 ◽  
Author(s):  
Irene Schicker ◽  
Petrina Papazek
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Wind Speed ◽  
Wind Turbines ◽  
Wind Farm ◽  
Construction Material ◽  
Information Source ◽  
Estimation Algorithm ◽  
Average Wind Speed ◽  
Average Wind

<p>Wind gusts and high wind speeds need to be considered in wind power industry and power grid management as they affect construction, material, siting and maintenance of turbines and power lines. Furthermore, gusts are an important information source on turbulence conditions in the atmosphere at the respective sites.<br>Often, the wind farm operators only provide basic data of the turbines such as average wind speed, direction, power and temperature. However, they require forecasts of gusts, too. Thus, a simple gust estimation algorithm based on the average wind speed was developed. The algorithm is tested at different mast measurement sites and WFIP2 data and applied to selected wind turbines. Results show that the algorithm is skillful enough to be used as a first guess gust estimation for single turbines and is, thus, used for nowcasting.<br>For nowcasting for the first two hours with a temporal fequency of ten minutes solely observations are used. A high-frequency wind speed and gust nowcasting ensemble based on different machine learning methodologies, including an ensemble for every method, was developd. Used are boosting, random forest, linear regression, a simple monte carlo method and a feed forward neural network. Results show that perturbing the observations provides a good forecasting spread for at least some of the methods. However, for other methods the spread is reduced significantly. Most of the used methods are able to provide good forecastst. However, hyperparameter tuning for the lightGBM boosting algorithm and the neural network is still needed.</p>

scholarly journals Impact of weather conditions on cheetah monitoring with scat detection dogs

2021 ◽  
pp. 1-6
Author(s):  
Noreen M. Mutoro ◽  
Jonas Eberle ◽  
Jana S. Petermann ◽  
Gertrud Schaab ◽  
Mary Wykstra ◽  
...  
Keyword(s):  
Wind Speed ◽  
Weather Conditions ◽  
Assessment Tools ◽  
Average Wind Speed ◽  
Strong Negative Correlation ◽  
Detection Rates ◽  
Average Wind ◽  
Invasive Method ◽  
Detection Dog ◽  
The Impact

Abstract Knowledge on cheetah population densities across their current range is limited. Therefore, new and efficient assessment tools are needed to gain more knowledge on species distribution, ecology and behaviour. Scat detection dogs have emerged as an efficient and non-invasive method to monitor elusive and vulnerable animal species, like cheetahs, due to the dog’s superior olfactory system. However, the success of locating scat using detection dogs can be significantly improved under suitable weather conditions. We examined the impact of temperature, humidity and wind speed on detection rates of scat from cheetahs during a scat detection dog survey in Northern Kenya. We found that average wind speed positively influences the scat detection rate of detection dogs working on leash. Humidity showed no significant influence. Temperature showed a strong negative correlation with humidity and thus was excluded from our model analyses. While it is likely that wind speed is especially invalid for dogs working off leash, this study did not demonstrate this. Wind speed could thus influence the success of monitoring cheetahs or other target species. Our findings help to improve the survey and thus maximise the coverage of study area and the collection of target samples of elusive and rare species.

scholarly journals Lake Michigan Wind Assessment Analysis, 2012 and 2013

2017 ◽  
Vol 6 (1) ◽  
pp. 19-27
Author(s):  
Charles R Standridge ◽  
Daivd Zeitler ◽  
Aaron Clark ◽  
Tyson Spoolma ◽  
Erik Nordman ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Wind Farm ◽  
Lake Michigan ◽  
Floating Platform ◽  
Energy Potential ◽  
Average Wind Speed ◽  
Average Wind ◽  
Wind Energy Potential ◽  
Lower Height

A study was conducted to address the wind energy potential over Lake Michigan to support a commercial wind farm.  Lake Michigan is an inland sea in the upper mid-western United States.  A laser wind sensor mounted on a floating platform was located at the mid-lake plateau in 2012 and about 10.5 kilometers from the eastern shoreline near Muskegon Michigan in 2013.  Range gate heights for the laser wind sensor were centered at 75, 90, 105, 125, 150, and 175 meters.  Wind speed and direction were measured once each second and aggregated into 10 minute averages.  The two sample t-test and the paired-t method were used to perform the analysis.  Average wind speed stopped increasing between 105 m and 150 m depending on location.  Thus, the collected data is inconsistent with the idea that average wind speed increases with height. This result implies that measuring wind speed at wind turbine hub height is essential as opposed to using the wind energy power law to project the wind speed from lower heights.  Average speed at the mid-lake plateau is no more that 10% greater than at the location near Muskegon.  Thus, it may be possible to harvest much of the available wind energy at a lower height and closer to the shoreline than previously thought.  At both locations, the predominate wind direction is from the south-southwest.  The ability of the laser wind sensor to measure wind speed appears to be affected by a lack of particulate matter at greater heights.Article History: Received June 15th 2016; Received in revised form January 16th 2017; Accepted February 2nd 2017 Available onlineHow to Cite This Article: Standridge, C., Zeitler, D., Clark, A., Spoelma, T., Nordman, E., Boezaart, T.A., Edmonson, J.,  Howe, G., Meadows, G., Cotel, A. and Marsik, F. (2017) Lake Michigan Wind Assessment Analysis, 2012 and 2013. Int. Journal of Renewable Energy Development, 6(1), 19-27.http://dx.doi.org/10.14710/ijred.6.1.19-27

scholarly journals Observed and simulated turbulent kinetic energy (WRF 3.8.1) overlarge offshore wind farms

2019 ◽  
Author(s):  
Simon K. Siedersleben ◽  
Andreas Platis ◽  
Julie K. Lundquist ◽  
Bughsin Djath ◽  
Astrid Lampert ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Wind Farm ◽  
Wind Farms ◽  
Horizontal Resolution ◽  
Offshore Wind ◽  
Vertical Resolution ◽  
Offshore Wind Farms ◽  
The Impact ◽  
Simulated Wind

Abstract. Because wind farms affect local weather and microclimates, parameterizations of their effects have been developed for numerical weather prediction models. While most wind farm parameterizations (WFP) include drag effects of wind farms, models differ on whether or not an additional turbulent kinetic energy (TKE) source should be included in these parameterizations to simulate the impact of wind farms on the boundary layer. Therefore, we use aircraft measurements above large offshore wind farms in stable conditions to evaluate WFP choices. Of the three case studies we examine, we find the simulated ambient background flow to agree with observations of temperature stratification and winds. This agreement allowing us to explore the sensitivity of simulated wind farm effects with respect to modeling choices such as whether or not to include a TKE source, horizontal resolution, vertical resolution, and advection of TKE. For a stably stratified marine atmospheric boundary layer (MABL), a TKE source and a horizontal resolution in the order of 5 km or finer are necessary to represent the impact of offshore wind farms on the MABL. Additionally, TKE advection results in excessively reduced TKE over the wind farms, which in turn causes an underestimation of the wind speed above the wind farm. Furthermore, using fine vertical resolution increases the agreement of the simulated wind speed with satellite observations of surface wind speed.

A Study of Estimation of Wind Potential and Prediction of Grid-Connected Wind Power Development in Vietnam

2020 ◽  
Vol 11 (2) ◽  
pp. 27-37
Author(s):  
Co Xuan Hoang ◽  
Linh Thi Hai Dang ◽  
Da Van Ta ◽  
Cuong Manh Dinh ◽  
Chinh Van Kim ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Power ◽  
Power Plants ◽  
Wind Farms ◽  
Ground Level ◽  
Correlation Equation ◽  
Electricity Production ◽  
Average Wind Speed ◽  
Average Wind ◽  
Wind Potential

The construction of grid-connected wind power plants has increased sharply in Vietnam due to the rapid rise of energy demands. Previous studies of wind energy have shown that the wind potential of Vietnam compared to other countries of Southeast Asia and examined wind speed levels of each region of Vietnam. In this study, the annual electricity production (AEP), which is an important factor of project's cost and benefit calculation, was calculated for 13 study areas. A correlation equation between AEP and the average wind speed at 60m above ground level was also developed to estimate AEP where there exists only data of the annual average wind speed. Moreover, other resources of the development of grid-connected wind power were discussed in this research such as the Vietnamese supporting mechanism, international co-operation, turbine technology development, etc. The article then predicts the trend, and proposes some recommendations of developing grid-connected wind farms in Vietnam.

scholarly journals THE IMPACT OF LONG CANYON DESIGN AND WATERFRONT BARRIER BUILDINGS ON WIND VELOCITY IN A COASTAL AREA OF SELATPANJANG CITY

Arsitektura ◽  
2018 ◽  
Vol 16 (2) ◽  
pp. 231 ◽  
Author(s):  
Boby Rahman ◽  
Asri Dinapradipta ◽  
Ima Defiana
Keyword(s):  
Wind Speed ◽  
Urban Environments ◽  
Average Wind Speed ◽  
Speed Reduction ◽  
Speed Distribution ◽  
Average Wind ◽  
Wind Speed Distribution ◽  
Urban Waterfront ◽  
Wind Distribution ◽  
The Impact

<p class="Abstract"><em>The increase of waterfront buildings’ height has an effect on wind distribution in the urban canyon. On the other hand, the distribution of wind is needed in providing thermal balance in urban environments, especially in urban waterfront coastal areas. This study aimed at observing and analyzing the effect of building height (H) on waterfront buildings and aspects of the length to width (L/W) ratio related to the length of the canyon design. The observation was focused on the wind speed distribution. The research was an experimental research using ENVI-met V3.1 software for simulation. The results indicated that short canyon (low L/W value) results in lower wind speed changes compared to that of long one (higher L/W value) at all altitude levels. The short canyons provided more stability in wind speed reduction. The 15 meters wide of canyon design contributed to the highest average wind speed. Overall, the existence of a barrier building would result in a negative area of air flow and create a calm area within the distance of  ± 50 meters.</em></p><em></em>

scholarly journals Turbulent kinetic energy over large offshore wind farms observed and simulated by the mesoscale model WRF (3.8.1)

2020 ◽  
Vol 13 (1) ◽  
pp. 249-268 ◽  
Author(s):  
Simon K. Siedersleben ◽  
Andreas Platis ◽  
Julie K. Lundquist ◽  
Bughsin Djath ◽  
Astrid Lampert ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Wind Farm ◽  
Wind Farms ◽  
Horizontal Resolution ◽  
Offshore Wind ◽  
Vertical Resolution ◽  
Offshore Wind Farms ◽  
The Impact ◽  
Simulated Wind

Abstract. Wind farms affect local weather and microclimates; hence, parameterizations of their effects have been developed for numerical weather prediction models. While most wind farm parameterizations (WFPs) include drag effects of wind farms, models differ on whether or not an additional turbulent kinetic energy (TKE) source should be included in these parameterizations to simulate the impact of wind farms on the boundary layer. Therefore, we use aircraft measurements above large offshore wind farms in stable conditions to evaluate WFP choices. Of the three case studies we examine, we find the simulated ambient background flow to agree with observations of temperature stratification and winds. This agreement allows us to explore the sensitivity of simulated wind farm effects with respect to modeling choices such as whether or not to include a TKE source, horizontal resolution, vertical resolution and advection of TKE. For a stably stratified marine atmospheric boundary layer (MABL), a TKE source and a horizontal resolution on the order of 5 km or finer are necessary to represent the impact of offshore wind farms on the MABL. Additionally, TKE advection results in excessively reduced TKE over the wind farms, which in turn causes an underestimation of the wind speed deficit above the wind farm. Furthermore, using fine vertical resolution increases the agreement of the simulated wind speed with satellite observations of surface wind speed.

Copula-Based Security Assessment of Power Insulators Influenced by the Storm

2011 ◽  
Vol 55-57 ◽  
pp. 849-852
Author(s):  
Zhao Kun Wang ◽  
Jun Yi ◽  
Ming Yong Lai ◽  
Bao Ping Liu
Keyword(s):  
Wind Speed ◽  
Meteorological Factors ◽  
Daily Rainfall ◽  
Hunan Province ◽  
Security Assessment ◽  
Rainfall Distribution ◽  
Average Wind Speed ◽  
Daily Average ◽  
Average Wind ◽  
The Impact

In this paper the model of Copula-based security assessment of power insulators under the impact of the storm is proposed. The model firstly analysis the daily average winds speed, the historical daily rainfall data to get the probability of wind speed and daily rainfall distribution. Then presents the model of security assessment of power insulators under the impact of wind and rainfall by considering not only the probability of relevance between the daily average wind speed and daily rainfall by using Copula join function, but also the combination of meteorological factors on the impact of power insulators security. This work was supported by the Key Scientific and Technological Project of Hunan Province of China (2008FJ1006).

Sensitivity of Wind Farm Output to Wind Conditions, Land Configuration, and Installed Capacity, Under Different Wake Models

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Weiyang Tong ◽  
Souma Chowdhury ◽  
Ali Mehmani ◽  
Achille Messac ◽  
Jie Zhang
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Wind Farm ◽  
Input Parameter ◽  
Wind Farms ◽  
Key Factors ◽  
Sensitivity Indices ◽  
Wind Farm Design ◽  
The Impact ◽  
Farm Design

In conventional wind farm design and optimization, analytical wake models are generally used to estimate the wake-induced power losses. Different wake models often yield significantly dissimilar estimates of wake velocity deficit and wake width. In this context, the wake behavior, as well as the subsequent wind farm power generation, can be expressed as functions of a series of key factors. A quantitative understanding of the relative impact of each of these key factors, particularly under the application of different wake models, is paramount to reliable quantification of wind farm power generation. Such an understanding is however not readily evident in the current state of the art in wind farm design. To fill this important gap, this paper develops a comprehensive sensitivity analysis (SA) of wind farm performance with respect to the key natural and design factors. Specifically, the sensitivities of the estimated wind farm power generation and maximum farm output potential are investigated with respect to the following key factors: (i) incoming wind speed, (ii) ambient turbulence, (iii) land area per MW installed, (iv) land aspect ratio, and (v) nameplate capacity. The extended Fourier amplitude sensitivity test (e-FAST), which helpfully provides a measure of both first-order and total-order sensitivity indices, is used for this purpose. The impact of using four different analytical wake models (i.e., Jensen, Frandsen, Larsen, and Ishihara models) on the wind farm SA is also explored. By applying this new SA framework, it was observed that, when the incoming wind speed is below the turbine rated speed, the impact of incoming wind speed on the wind farm power generation is dominant, irrespective of the choice of wake models. Interestingly, for array-like wind farms, the relative importance of each input parameter was found to vary significantly with the choice of wake models, i.e., appreciable differences in the sensitivity indices (of up to 70%) were observed across the different wake models. In contrast, for optimized wind farm layouts, the choice of wake models was observed to have marginal impact on the sensitivity indices.

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