Smoothing Control of Wind Farm Output by Considering State of Kinetic Energy of Wind Farm

2016 ◽  
Author(s):  
K. Kanawa ◽  
K. Koiwa ◽  
A. Umemura ◽  
R. Takahashi ◽  
J. Tamura
Keyword(s):  
Kinetic Energy ◽  
Wind Farm

scholarly journals Local and Mesoscale Impacts of Wind Farms as Parameterized in a Mesoscale NWP Model

2012 ◽  
Vol 140 (9) ◽  
pp. 3017-3038 ◽  
Author(s):  
Anna C. Fitch ◽  
Joseph B. Olson ◽  
Julie K. Lundquist ◽  
Jimy Dudhia ◽  
Alok K. Gupta ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Kinetic Energy ◽  
Wind Farm ◽  
Weather Prediction ◽  
Wind Farms ◽  
Mean Flow ◽  
Thrust Coefficient ◽  
Near Surface ◽  
Neutral Boundary Layer

Abstract A new wind farm parameterization has been developed for the mesoscale numerical weather prediction model, the Weather Research and Forecasting model (WRF). The effects of wind turbines are represented by imposing a momentum sink on the mean flow; transferring kinetic energy into electricity and turbulent kinetic energy (TKE). The parameterization improves upon previous models, basing the atmospheric drag of turbines on the thrust coefficient of a modern commercial turbine. In addition, the source of TKE varies with wind speed, reflecting the amount of energy extracted from the atmosphere by the turbines that does not produce electrical energy. Analyses of idealized simulations of a large offshore wind farm are presented to highlight the perturbation induced by the wind farm and its interaction with the atmospheric boundary layer (BL). A wind speed deficit extended throughout the depth of the neutral boundary layer, above and downstream from the farm, with a long wake of 60-km e-folding distance. Within the farm the wind speed deficit reached a maximum reduction of 16%. A maximum increase of TKE, by nearly a factor of 7, was located within the farm. The increase in TKE extended to the top of the BL above the farm due to vertical transport and wind shear, significantly enhancing turbulent momentum fluxes. The TKE increased by a factor of 2 near the surface within the farm. Near-surface winds accelerated by up to 11%. These results are consistent with the few results available from observations and large-eddy simulations, indicating this parameterization provides a reasonable means of exploring potential downwind impacts of large wind farms.

scholarly journals Enhancement of Power System Transient Stability by Active and Reactive Power Control of Variable Speed Wind Generators

2020 ◽  
Vol 10 (24) ◽  
pp. 8874
Author(s):  
Masaki Yagami ◽  
Masanori Ichinohe ◽  
Junji Tamura
Keyword(s):  
Kinetic Energy ◽  
Power System ◽  
Power Control ◽  
Wind Farm ◽  
Transient Stability ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Variable Speed ◽  
Pv System ◽  
Reactive Power Control

This paper proposes a novel control method for enhancing transient stability by using renewable energy sources (RES). The kinetic energy accumulated in a rotor of variable speed wind generator (VSWG) is proactively used as the active power source, which is controlled according to the frequency measured at the wind farm. In addition, coordinated reactive power control according to the grid voltage is also carried out to more effectively use the kinetic energy of the VSWG. The effects of the proposed control system were evaluated by simulation analyses performed using a modified IEEE nine-bus power system network made up of synchronous generators (SGs), a photovoltaic (PV) system and a VSWG-based wind farm. Furthermore, the coordinated reactive power control between the VSWG and PV system was also demonstrated.

Two Corrections for Turbulent Kinetic Energy Generated by Wind Farms in the WRF Model

2020 ◽  
Vol 148 (12) ◽  
pp. 4823-4835
Author(s):  
Cristina L. Archer ◽  
Sicheng Wu ◽  
Yulong Ma ◽  
Pedro A. Jiménez
Keyword(s):  
Wind Speed ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Wind Farm ◽  
Atmospheric Stability ◽  
Wrf Model ◽  
Wind Farms ◽  
Near Surface ◽  
Large Eddy ◽  
The Way

AbstractAs wind farms grow in number and size worldwide, it is important that their potential impacts on the environment are studied and understood. The Fitch parameterization implemented in the Weather Research and Forecasting (WRF) Model since version 3.3 is a widely used tool today to study such impacts. We identified two important issues related to the way the added turbulent kinetic energy (TKE) generated by a wind farm is treated in the WRF Model with the Fitch parameterization. The first issue is a simple “bug” in the WRF code, and the second issue is the excessive value of a coefficient, called CTKE, that relates TKE to the turbine electromechanical losses. These two issues directly affect the way that a wind farm wake evolves, and they impact properties like near-surface temperature and wind speed at the wind farm as well as behind it in the wake. We provide a bug fix and a revised value of CTKE that is one-quarter of the original value. This 0.25 correction factor is empirical; future studies should examine its dependence on parameters such as atmospheric stability, grid resolution, and wind farm layout. We present the results obtained with the Fitch parameterization in the WRF Model for a single turbine with and without the bug fix and the corrected CTKE and compare them with high-fidelity large-eddy simulations. These two issues have not been discovered before because they interact with one another in such a way that their combined effect is a somewhat realistic vertical TKE profile at the wind farm and a realistic wind speed deficit in the wake. All WRF simulations that used the Fitch wind farm parameterization are affected, and their conclusions may need to be revisited.

Wind farm contribution to frequency regulation by distributed adaptive kinetic energy control

2017 ◽  
Author(s):  
Francesco Conte ◽  
Monica Crosa di Vergagni ◽  
Stefano Massucco ◽  
Federico Silvestro ◽  
Theodor S. Borsche
Keyword(s):  
Kinetic Energy ◽  
Wind Farm ◽  
Frequency Regulation ◽  
Energy Control

scholarly journals Quantification of Preferential Contribution of Reynolds Shear Stresses and Flux of Mean Kinetic Energy Via Conditional Sampling in a Wind Turbine Array

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Hawwa Falih Kadum ◽  
Devin Knowles ◽  
Raúl Bayoán Cal
Keyword(s):  
Shear Stress ◽  
Kinetic Energy ◽  
Wind Turbine ◽  
Momentum Flux ◽  
Wind Farm ◽  
Reynolds Shear Stress ◽  
Stress Component ◽  
Wake Flow ◽  
Shear Stresses ◽  
Balanced Distribution

Conditional statistics are employed in analyzing wake recovery and Reynolds shear stress (RSS) and flux directional out of plane component preference. Examination of vertical kinetic energy entrainment through describing and quantifying the aforementioned quantities has implications on wind farm spacing, design, and power production, and also on detecting loading variation due to turbulence. Stereographic particle image velocimetry measurements of incoming and wake flow fields are taken for a 3 × 4 model wind turbine array in a scaled wind tunnel experiment. Reynolds shear stress component is influenced by ⟨uv⟩ component, whereas ⟨vw⟩ is more influenced by streamwise advection of the flow; u, v, and w being streamwise, vertical, and spanwise velocity fluctuations, respectively. Relative comparison between sweep and ejection events, ΔS⟨uiuj⟩, shows the role of streamwise advection of momentum on RSS values and direction. It also shows their tendency to an overall balanced distribution. ⟨uw⟩ intensities are associated with ejection elevated regions in the inflow, yet in the wake, ⟨uw⟩ is linked with sweep dominance regions. Downward momentum flux occupies the region between hub height and top tip. Sweep events contribution to downward momentum flux is marginally greater than ejection events'. When integrated over the swept area, sweeps contribute 55% of the net downward kinetic energy flux and 45% is the ejection events contribution. Sweep dominance is related to momentum deficit as its value in near wake elevates 30% compared to inflow. Understanding these quantities can lead to improved closure models.

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