Wind Turbine Field Measurements With Compact Microphone Array Using Advanced Beamforming Methods

Author(s):  
Rakesh Ramachandran ◽  
Ganesh Raman ◽  
Robert Dougherty
2019 ◽  
Vol 146 ◽  
pp. 295-309 ◽  
Author(s):  
Cui Qing Zhang ◽  
Zhi Ying Gao ◽  
Yong Yan Chen ◽  
Yuan Jun Dai ◽  
Jian Wen Wang ◽  
...  

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2102 ◽  
Author(s):  
Torben Reichstein ◽  
Alois Peter Schaffarczyk ◽  
Christoph Dollinger ◽  
Nicolas Balaresque ◽  
Erich Schülein ◽  
...  

Knowledge about laminar–turbulent transition on operating multi megawatt wind turbine (WT) blades needs sophisticated equipment like hot films or microphone arrays. Contrarily, thermographic pictures can easily be taken from the ground, and temperature differences indicate different states of the boundary layer. Accuracy, however, is still an open question, so that an aerodynamic glove, known from experimental research on airplanes, was used to classify the boundary-layer state of a 2 megawatt WT blade operating in the northern part of Schleswig-Holstein, Germany. State-of-the-art equipment for measuring static surface pressure was used for monitoring lift distribution. To distinguish the laminar and turbulent parts of the boundary layer (suction side only), 48 microphones were applied together with ground-based thermographic cameras from two teams. Additionally, an optical camera mounted on the hub was used to survey vibrations. During start-up (SU) (from 0 to 9 rpm), extended but irregularly shaped regions of a laminar-boundary layer were observed that had the same extension measured both with microphones and thermography. When an approximately constant rotor rotation (9 rpm corresponding to approximately 6 m/s wind speed) was achieved, flow transition was visible at the expected position of 40% chord length on the rotor blade, which was fouled with dense turbulent wedges, and an almost complete turbulent state on the glove was detected. In all observations, quantitative determination of flow-transition positions from thermography and microphones agreed well within their accuracy of less than 1%.


2014 ◽  
Vol 62 (2) ◽  
pp. 90-101 ◽  
Author(s):  
Hideki Tachibana ◽  
Hiroo Yano ◽  
Akinori Fukushima ◽  
Shinichi Sueoka

Author(s):  
Dan Zimmerle ◽  
Oliver Pacific ◽  
Nathan Howard

To better understand the effect of significant wind power production on distributed electrical networks, a Wind Turbine Simulator (WTS) was incorporated into the Grid Simulation Laboratory (GSL) at Colorado State University. This paper discusses the development of the engine controls, gain tuning and response matching to field measurements of wind turbines. Response was characterized while connected to the transmission grid, similar to the field information, using a series of transient events gleaned from field information. Transients caused by breaker events, which emulate connecting or disconnecting the individual wind turbines, were also considered. While overall correlation between commanded and actual power output was strong, several limitations were identified and are described.


Author(s):  
M. D. Pandey ◽  
H. J. Sutherland

Robust estimation of wind turbine design loads for service lifetimes of 30 to 50 years that are based on field measurements of a few days is a challenging problem. Estimating the long-term load distribution involves the integration of conditional distributions of extreme loads over the mean wind speed and turbulence intensity distributions. However, the accuracy of the statistical extrapolation is fairly sensitive to both model and sampling errors. Using measured inflow and structural data from the LIST program, this paper presents a comparative assessment of extreme loads using three distributions: namely, the Gumbel, Weibull and Generalized Extreme Value distributions. The paper uses L-moments, in place of traditional product moments, to reduce the sampling error. The paper discusses the application of extreme value theory and highlights its practical limitations. The proposed technique has the potential of improving estimates of the design loads for wind turbines.


Energy ◽  
2020 ◽  
Vol 200 ◽  
pp. 117515
Author(s):  
Guangxing Wu ◽  
Chaoyu Zhang ◽  
Chang Cai ◽  
Ke Yang ◽  
Kezhong Shi

Author(s):  
Hui Hu ◽  
Ahmet Ozbay ◽  
Wei Tian ◽  
Zifeng Yang

An experimental study was conducted to investigate the interferences of wind turbines sited over hilly terrains in order to elucidate underlying physics to explore/optimize design paradigms of wind turbines sited over complex terrains for higher power yield and better durability. The experiments were conducted in a large wind tunnel with of wind turbine models sited over a flat terrain (baseline case) and a 2D-ridge with non-homogenous atmospheric boundary layer winds. In addition to measuring dynamic wind loads (both forces and moments) and the power outputs of the wind turbine models, a high-resolution digital Particle Image Velocimetry (PIV) system was used to conduct detailed flow field measurements to quantify the flow characteristics of the surface winds and wake interferences among multiple wind turbines over flat (baseline case) and complex terrains. The detailed flow field measurements were correlated with the wind load measurements and power outputs of the wind turbine models to elucidate the underlying physics associated with turbine power generation and fatigue loads acting on the wind turbines.


2021 ◽  
Author(s):  
Peter Andreas Brugger ◽  
Corey D. Markfort ◽  
Fernando Porté-Agel

Abstract. Wake meandering is a low-frequency oscillation of the entire wind turbine wake that can contribute to power and load fluctuations of downstream turbines in wind farms. Field measurements of two Doppler LiDARs mounted on the nacelle of a utility-scale wind turbine were used to investigate relationships between the inflow and the wake meandering as well as the effect of wake meandering on the temporally averaged wake. A correlation analysis showed a linear relationship between the instantaneous wake position and the lateral velocity that degraded with the evolution of the turbulent wind field during the time of downstream advection. A low-pass filter proportional to the advection time delay is recommended to remove small scales that become decorrelated even for distances within the typical spacing of wind turbine rows in a wind farm. The results also showed that the velocity at which wake meandering is transported downstream was slower than the inflow wind speed, but faster than the velocity at the wake center. This indicates that the modelling assumption of the wake as an passive scalar should be revised in the context of the downstream advection. Further, the strength of wake meandering increased linearly with the turbulence intensity of the lateral velocity and with the downstream distance. Wake meandering reduced the maximum velocity deficit of the temporally averaged wake and increased its width. Both effects scaled with the wake meandering strength. Lastly, we found that the fraction of the wake turbulence intensity that was caused by wake meandering decreased with downstream distance contrary to the wake meandering strength.


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