scholarly journals WRF Modeling of Deep Convection and Hail for Wind Power Applications

2020 ◽  
Vol 59 (10) ◽  
pp. 1717-1733 ◽  
Author(s):  
F. Letson ◽  
T. J. Shepherd ◽  
R. J. Barthelmie ◽  
S. C. Pryor

AbstractDeep convection and the related occurrence of hail, intense precipitation, and wind gusts represent a hazard to a range of energy infrastructure including wind turbine blades. Wind turbine blade leading-edge erosion (LEE) is caused by the impact of falling hydrometeors onto rotating wind turbine blades. It is a major source of wind turbine maintenance costs and energy losses from wind farms. In the U.S. southern Great Plains (SGP), where there is widespread wind energy development, deep convection and hail events are common, increasing the potential for precipitation-driven LEE. A 25-day Weather Research and Forecasting (WRF) Model simulation conducted at convection-permitting resolution and using a detailed microphysics scheme is carried out for the SGP to evaluate the effectiveness in modeling the wind and precipitation conditions relevant to LEE potential. WRF output for these properties is evaluated using radar observations of precipitation (including hail) and reflectivity, in situ wind speed measurements, and wind power generation. This research demonstrates some skill for the primary drivers of LEE. Wind speeds, rainfall rates, and precipitation totals show good agreement with observations. The occurrence of precipitation during power-producing wind speeds is also shown to exhibit fidelity. Hail events frequently occur during periods when wind turbines are rotating and are especially important to LEE in the SGP. The presence of hail is modeled with a mean proportion correct of 0.77 and an odds ratio of 4.55. Further research is needed to demonstrate sufficient model performance to be actionable for the wind energy industry, and there is evidence for positive model bias in cloud reflectivity.

2017 ◽  
Vol 29 (17) ◽  
pp. 3426-3435
Author(s):  
Sang-Hyeon Kang ◽  
Lae-Hyong Kang

Over the past several decades, wind turbines have been established as one of the promising renewable energy systems for safe and clean energy collection. In order to collect more energy efficiently, the size of wind turbines has been increased and many wind farms have been constructed. Wind farms generate lots of energy, but they cause several side effects, such as noise and a threat to wildlife. It is reported that the bird collision rate of a wind turbine ranges from 0.01 to 23 annually. It is more serious in the case of rare and endangered birds. In order to monitor the effect on birds in wind farms, researchers have developed remote sensing technology for a detection apparatus using heat and radar. In addition, paint color and other variables have been studied regarding their effects on the collision rate. However, the existing methods are passive ways to prevent bird collision or just monitor bird conditions. Therefore, in this study, we propose a bird collision monitoring system that can detect where the bird collision occurred, which will aid in rescuing the birds. If the wind turbine blade has its own ability to capture an impact signal, the impact location can be easily detected, and the birds can be rescued. For this purpose, piezoelectric paint was applied to the wind turbine blades used in this study. The piezoelectric paint is also known as 0-3 piezoelectric composite, which is composed of piezoelectric particles and polymer resin. It is sensitive to high-frequency signals such as impacts, so it is suitable for monitoring bird collision signals. In order to amplify and transmit the impact signal from the rotating blade to a stationary base, a wireless transmission device using a ZigBee module and signal conditioning circuit was also installed. Through lab-scale tests, it was confirmed that this bird collision monitoring system shows a 100% bird collision detection rate.


2018 ◽  
Vol 46 ◽  
pp. 00006
Author(s):  
Krzysztof Pytel ◽  
Szymon Szpin ◽  
Wiktor Hudy ◽  
Małgorzata Piaskowska–Silarska ◽  
Stanisław Gumuła

The aim of this study was a comparative analysis of the suitability of the use of airfoil for wind power. Based on numerical analyses and analytical methods, information on the power factor was obtained. The analyses were carried out for the wind turbine blades and rotors of a vertical axis wind turbine. The tests were performed for the constructed profile and compared with the profile DU 06-W-200 used in the construction of a wind turbine rotors. A vertical axis wind turbine model equipped with designed blade profiles was prepared. The main predicted purpose of the device is to supply electricity to the household. The blade profile models were prepared and then a numerical analysis was performed using the CFD application. The obtained results for given wind speeds and types of profiles were compared with each other. The conducted research allowed to determine the sense of applying the unaudited profile based on the determined value of wind turbine power coefficient. Studies have shown that the accurate preparation of the optimal rotor blade with respect to flow of air stream strongly influences the characteristics of the wind turbine.


Author(s):  
Fardin Khalili ◽  
Pradip Majumdar ◽  
Mehdi Zeyghami

Far-field noise propagation from wind turbines propel development of wind farms to an issue for public acceptance. Airstream contains pressure fluctuations as a result of instability, giving a regular eddy pattern or an irregular turbulent motion which are responsible for the sound produced by wind turbine blades. Aeroacoustic noise emanated from a wind turbine is mainly generated by the interactions of tip and trailing edge of wind turbine blades with the mechanics in wake region such as inflow turbulence structures, boundary layer separation and vortex shedding. Hence, there is a strong necessity for an analytical investigation for noise reducing design and development of the technology in order to further expand wind farms. The objectives of this study are to analyze the far-field aeroacoustics of wind turbines with the purpose of predicting far-field sound pressure levels at different receivers and monitoring total acoustic power captured within wind turbine performance for various wind speeds. Blades are modeled based on NREL S825 airfoil since it has high maximum lift and low profile drag. With the purpose of predicting far-field noise, the Ffowcs Williams-Hawkings (FW-H) acoustics model is the preferred method in order to compute the far-field sound signal which is released from near-field flow. As the key attribute of the research, detached eddy simulation (DES) provides accurate results for the desired simulation since it is a hybrid modeling approach that combines features of Reynolds-averaged Navier-Stokes (RANS) simulation in boundary layers and irrotational flow regions, and large-eddy simulation (LES) in unsteady separation regions. In addition, SST K-Omega detached eddy turbulence model is used due to its good compromise between robustness, computational cost and accuracy. Aerodynamic and aeroacoustic analysis of a wind turbine is performed using a three-dimensional model and a commercial CFD Software, STAR-CCM+. In order to predict far-field sound pressure levels and acoustic powers on different locations, five point receivers are defined downstream of the wind turbine model. Receivers are placed one diameter, D, over the wind turbine rotor blades with 1D, 2D, 5D, 10D and 15D away from the wind turbine that represent receivers 1 to 5. Higher acoustic powers are delivered at closer receivers. It means that acoustic power fades out with larger distances. It is observed that there is a fractional variation of 61%, 17%, 6% and 3% as compared to the receiver 1 for receivers 2, 3, 4 and 5 respectively. Moreover, the results show that variation in total acoustic power is non-linear and higher acoustic powers will be captured for higher velocities. This comparison is done between wind speeds of 10m/s and 15m/s.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2319
Author(s):  
Hyun-Goo Kim ◽  
Jin-Young Kim

This study analyzed the performance decline of wind turbine with age using the SCADA (Supervisory Control And Data Acquisition) data and the short-term in situ LiDAR (Light Detection and Ranging) measurements taken at the Shinan wind farm located on the coast of Bigeumdo Island in the southwestern sea of South Korea. Existing methods have generally attempted to estimate performance aging through long-term trend analysis of a normalized capacity factor in which wind speed variability is calibrated. However, this study proposes a new method using SCADA data for wind farms whose total operation period is short (less than a decade). That is, the trend of power output deficit between predicted and actual power generation was analyzed in order to estimate performance aging, wherein a theoretically predicted level of power generation was calculated by substituting a free stream wind speed projecting to a wind turbine into its power curve. To calibrate a distorted wind speed measurement in a nacelle anemometer caused by the wake effect resulting from the rotation of wind-turbine blades and the shape of the nacelle, the free stream wind speed was measured using LiDAR remote sensing as the reference data; and the nacelle transfer function, which converts nacelle wind speed into free stream wind speed, was derived. A four-year analysis of the Shinan wind farm showed that the rate of performance aging of the wind turbines was estimated to be −0.52%p/year.


2021 ◽  
Author(s):  
Alessio Castorrini ◽  
Paolo Venturini ◽  
Fabrizio Gerboni ◽  
Alessandro Corsini ◽  
Franco Rispoli

Abstract Rain erosion of wind turbine blades represents an interesting topic of study due to its non-negligible impact on annual energy production of the wind farms installed in rainy sites. A considerable amount of recent research works has been oriented to this subject, proposing rain erosion modelling, performance losses prediction, structural issues studies, etc. This work aims to present a new method to predict the damage on a wind turbine blade. The method is applied here to study the effect of different rain conditions and blade coating materials, on the damage produced by the rain over a representative section of a reference 5MW turbine blade operating in normal turbulence wind conditions.


Author(s):  
Alka Gupta ◽  
Abdulrahman Alsultan ◽  
R. S. Amano ◽  
Sourabh Kumar ◽  
Andrew D. Welsh

Energy is the heart of today’s civilization and the demand seems to be increasing with our growing population. Alternative energy solutions are the future of energy, whereas the fossil-based fuels are finite and deemed to become extinct. The design of the wind turbine blade is the main governing factor that affects power generation from the wind turbine. Different airfoils, angle of twist and blade dimensions are the parameters that control the efficiency of the wind turbine. This study is aimed at investigating the aerodynamic performance of the wind turbine blade. In the present paper, we discuss innovative blade designs using the NACA 4412 airfoil, comparing them with a straight swept blade. The wake region was measured in the lab with a straight blade. All the results with different designs of blades were compared for their performance. A complete three-dimensional computational analysis was carried out to compare the power generation in each case for different wind speeds. It was found from the numerical analysis that the slotted blade yielded the most power generation among the other blade designs.


2021 ◽  
Vol 25 (1) ◽  
pp. 41-48
Author(s):  
Stanisław Chudzik

The article presents the results of research into the operation of a model of a wind micropower plant with a variable blade angle. The research was carried out on a miniature model of a measuring stand built for the purpose of carrying out work on pre-developed projects of wind micro power plants. The stand allows to carry out measurements related to the selection of the optimal propeller geometry, as well as the development and testing of algorithms for optimal control of the micropower plant. The physical basics of wind turbine operation and the methods of its optimal control are presented. The results of the performed measurements for the selected propeller blade geometry with the possibility of changing its setting angle are presented. A DC generator with a load with a non-linear characteristic in the form of a Li-Po battery cell was used. The results of operation of a simple MPPT control algorithm are presented. The lack of optimal control systems for the operation of micropower plants is dictated by the general belief that the costs of its production are high in relation to the possible improvement of the efficiency of micropower plants. Moreover, the practical methods of controlling larger wind turbines are not optimal for small and very small turbines. The conducted research focused on determining the possibility of using turbines with variable blade angles depending on its rotational speed. In larger wind farms, changing the blade angle is mainly used to limit the power of the turbine at high wind speeds. In micro wind power plants such solutions are not used for economic reasons. However, the use of a simple mechanism for changing the angle of the blades depending on the rotational speed of the propeller can increase the efficiency of the turbine in a wider range of wind speeds. The small dimensions of the research model allow for quick and cheap development of preliminary prototypes of turbine blades thanks to the possibility of using 3D printing technology.


2018 ◽  
Author(s):  
Sara C. Pryor ◽  
Tristan J. Shepherd ◽  
Rebecca J. Barthelmie

Abstract. Inter-annual variability (IAV) of expected annual energy production (AEP) from proposed wind farms plays a key role in dictating project financing. IAV in pre-construction projected AEP and the difference in 50th and 90th percentile (P50 and P90) AEP derives in part from variability in wind climates. However, the magnitude of IAV in wind speeds at/close to wind turbine hub-heights is poorly constrained and maybe overestimated by the 6 % standard deviation of annual mean wind speeds that is widely applied within the wind energy industry. Thus there is a need for improved understanding of the long-term wind resource and the inter-annual variability therein in order to generate more robust predictions of the financial value of a wind energy project. Long-term simulations of wind speeds near typical wind turbine hub-heights over the eastern USA indicate median gross capacity factors (computed using 10-minute wind speeds close to wind turbine hub-heights and the power curve of the most common wind turbine deployed in the region) that are in good agreement with values derived from operational wind farms. The IAV of annual mean wind speeds at/near to typical wind turbine hub-heights in these simulations is lower than is implied by assuming a standard deviation of 6 %. Indeed, rather than in 9 in 10 years exhibiting AEP within 0.9 and 1.1 times the long-term mean AEP, results presented herein indicate that over 90 % of the area in the eastern USA that currently has operating wind turbines simulated AEP lies within 0.94 and 1.06 of the long-term average. Further, IAV of estimated AEP is not substantially larger than IAV in mean wind speeds. These results indicate it may be appropriate to reduce the IAV applied to pre-construction AEP estimates to account for variability in wind climates, which would decrease the cost of capital for wind farm developments.


2020 ◽  
Vol 5 (3) ◽  
pp. 977-981 ◽  
Author(s):  
Anna-Maria Tilg ◽  
Charlotte Bay Hasager ◽  
Hans-Jürgen Kirtzel ◽  
Poul Hummelshøj

Abstract. Leading-edge erosion (LEE) of wind turbine blades is caused by the impact of hydrometeors, which appear in a solid or liquid phase. A reduction in the wind turbine blades' tip speed during defined precipitation events can mitigate LEE. To apply such an erosion-safe mode, a precipitation nowcast is required. Theoretical considerations indicate that the time a raindrop needs to fall to the ground is sufficient to reduce the tip speed. Furthermore, it is described that a compact, vertically pointing radar that measures rain at different heights with a sufficiently high spatio-temporal resolution can nowcast rain for an erosion-safe mode.


2021 ◽  
Author(s):  
◽  
Ramesh Kumar Behara

The growing needs for electric power around the world has resulted in fossil fuel reserves to be consumed at a much faster rate. The use of these fossil fuels such as coal, petroleum and natural gas have led to huge consequences on the environment, prompting the need for sustainable energy that meets the ever increasing demands for electrical power. To achieve this, there has been a huge attempt into the utilisation of renewable energy sources for power generation. In this context, wind energy has been identified as a promising, and environmentally friendly renewable energy option. Wind turbine technologies have undergone tremendous improvements in recent years for the generation of electrical power. Wind turbines based on doubly fed induction generators have attracted particular attention because of their advantages such as variable speed, constant frequency operation, reduced flicker, and independent control capabilities for maximum power point tracking, active and reactive powers. For modern power systems, wind farms are now preferably connected directly to the distribution systems because of cost benefits associated with installing wind power in the lower voltage networks. The integration of wind power into the distribution network creates potential technical challenges that need to be investigated and have mitigation measures outlined. Detailed in this study are both numerical and experimental models to investigate these potential challenges. The focus of this research is the analytical and experimental investigations in the integration of electrical power from wind energy into the distribution grid. Firstly, the study undertaken in this project was to carry out an analytical investigation into the integration of wind energy in the distribution network. Firstly, the numerical simulation was implemented in the MATLAB/Simulink software. Secondly, the experimental work, was conducted at the High Voltage Direct Centre at the University of KwaZulu-Natal. The goal of this project was to simulate and conduct experiments to evaluate the level of penetration of wind energy, predict the impact on the network, and propose how these impacts can be mitigated. From the models analysis, the effects of these challenges intensify with the increased integration of wind energy into the distribution network. The control strategies concept of the doubly fed induction generator connected wind turbine was addressed to ascertain the required control over the level of wind power penetration in the distribution network. Based on the investigation outcomes we establish that the impact on the voltage and power from the wind power integration in the power distribution system has a goal to maintain quality and balance between supply and demand.


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