Power Fluctuations in a Wind Farm Compared to a Single Turbine

Using a physics-based approach, we infer the impact of the coherence of atmospheric turbulence on the power fluctuations of wind farms. Application of the random-sweeping hypothesis reveals correlations characterized by advection and turbulent diffusion of coherent motions. Those contribute to local peaks and troughs in the power spectrum of the combined units at frequencies corresponding to the advection time between turbines, which diminish in magnitude at high frequencies. Experimental inspection supports the results from the random-sweeping hypothesis in predicting spectral characteristics, although the magnitude of the coherence spectrum appears to be over-predicted. This deviation is attributed to the presence of turbine wakes, and appears to be a function of the turbulence approaching the first turbine in a pair.

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Multi-Objective Optimization for Determining Trade-Off between Output Power and Power Fluctuations in Wind Farm System

Energies ◽

10.3390/en12224242 ◽

2019 ◽

Vol 12 (22) ◽

pp. 4242 ◽

Cited By ~ 2

Author(s):

Van-Hai Bui ◽

Akhtar Hussain ◽

Woon-Gyu Lee ◽

Hak-Man Kim

Keyword(s):

Output Power ◽

Wind Farm ◽

Optimal Operation ◽

Multi Objective Optimization ◽

Power Fluctuation ◽

Trade Off ◽

Multi Objective ◽

Optimal Output ◽

Power Fluctuations ◽

Optimal Set

In this paper, a multi-objective optimization method is proposed to determine trade-off between conflicting operation objectives of wind farm (WF) systems, i.e., maximizing the output power and minimizing the output power fluctuation of the WF system. A detailed analysis of the effects of different objective’s weight values and battery size on the operation of the WF system is also carried out. This helps the WF operator to decide on an optimal operation point for the whole system to increase its profit and improve output power quality. In order to find out the optimal solution, a two-stage optimization is also developed to determine the optimal output power of the entire system as well as the optimal set-points of wind turbine generators (WTGs). In stage 1, the WF operator performs multi-objective optimization to determine the optimal output power of the WF system based on the relevant information from WTGs’ and battery’s controllers. In stage 2, the WF operator performs optimization to determine the optimal set-points of WTGs for minimizing the power deviation and fulfilling the required output power from the previous stage. The minimization of the power deviation for the set-points of WTGs helps the output power of WTGs much smoother and therefore avoids unnecessary internal power fluctuations. Finally, different case studies are also analyzed to show the effectiveness of the proposed method.

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Enhancing LVRT Capability and Smoothing Power Fluctuations of a DFIG-based Wind Farm in a DC Microgrid

Electric Power Components and Systems ◽

10.1080/15325008.2017.1318979 ◽

2017 ◽

Vol 45 (10) ◽

pp. 1080-1090 ◽

Cited By ~ 7

Author(s):

Hamid Rezaie ◽

Sayyed Meelad Moosavy Chashmi ◽

Mojtaba Mirsalim ◽

Hassan Rastegar

Keyword(s):

Wind Farm ◽

Dc Microgrid ◽

Power Fluctuations

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The Effect of a Renewable Energy Certificate Incentive on Mitigating Wind Power Fluctuations: A Case Study of Jeju Island

Applied Sciences ◽

10.3390/app9081647 ◽

2019 ◽

Vol 9 (8) ◽

pp. 1647

Author(s):

Woong Ko ◽

Jaeho Lee ◽

Jinho Kim

Keyword(s):

Renewable Energy ◽

Power Systems ◽

Wind Power ◽

Wind Farm ◽

Optimization Problems ◽

Mixed Integer ◽

Renewable Portfolio Standard ◽

Flexible Resources ◽

Power Fluctuations ◽

Revenue Models

As renewable energy penetration in power systems grows, adequate energy policies are needed to support the system’s operations with flexible resources and to adopt more sustainable energies. A peak-biased incentive for energy storage systems (ESS) using the Korean renewable portfolio standard could make power system operations more difficult. For the first time in the research, this study evaluates the effect of imposing a renewable energy certificate incentive in off-peak periods on mitigating wind power fluctuations. We design a coordinated model of a wind farm with an ESS to model the behavior of wind farm operators. Optimization problems are formulated as mixed integer linear programming problems to test the implementation of revenue models under Korean policy. These models are designed to consider additional incentives for discharging the ESS during off-peak periods. The effects of imposing the incentives on wind power fluctuations are evaluated using the magnitude of the renewable energy certificate (REC) multiplier.

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Analysis on the Fluctuation of Wind Power

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.733.199 ◽

2015 ◽

Vol 733 ◽

pp. 199-202

Author(s):

Rui Hao Wang

Keyword(s):

Neural Network ◽

Energy Storage ◽

Wind Power ◽

Time Scales ◽

Wind Farm ◽

Power Grid ◽

Wind Farms ◽

Power Fluctuation ◽

Power Fluctuations ◽

Different Time Scales

This paper is aimed at exploring the characteristic fluctuation of wind power based on samples from a certain wind farm. First, the paper is to analyze fluctuations of wind power at different time scales. According to a sliding difference algorithm to build wind power fluctuations evaluation. Wind power fluctuation index for different time scales are used to fit probability distributions, indicating that the best form of distribution of wind power fluctuations is t location scale distribution. Secondly, considering the wind power has the characteristics of non-linear, non-stationary signal of the data, it fully meets the wavelet neural network analysis of the characteristics of the data. Therefore, select wavelet neural network training and testing so as to make predictions about the future of the total power of wind farm. It points out the differences between different regions covered by the index from the fluctuation characteristics of wind power, thus further understanding the fluctuation characteristics of wind power: Influenced by the time and space distribution and other factors, there is a big difference between the output power fluctuation characteristics of single wind generator and wind farm, which is because of the different wind machine in the field by the wind energy differences, and the wake effect of organic groups, making frequent fluctuations in power distribution; the fluctuation of wind is gentle, i.e. with increasing spatial distribution scale, so gentle effect occurs to wind power fluctuations. Finally, through the analysis of the fluctuation characteristics of power, power factor and analyses the influence of the characteristics of fluctuation, the paper draws a conclusion of the following improvement programs to overcome the adverse effects of wind power fluctuation of power grid operation: the rational allocation of energy storage devices, expanding the coverage area of a wind farm, or improving the design of the windmill, which will make wind farms adapt to different wind directions, thus eliminating the impact of fluctuations on the power grid from the wind farm power output by the energy storage device, and covering the area of large wind farms can adapt to different wind directions, and with power complementary, it has achieved the amount of stable power transmission into the grid.

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