Wind power is one of the most rapidly developing renewable energy around the world. Due to the high penetration of wind, large-scale wind farms in the power system could impact current operating strategy and frequency stability. Similar to the control of conventional power plant, set-point control of the wind farm gives an opportunity for the system operator to engage wind farms in active power dispatch. Taking a step further, scheduling wind power for some periods ahead can make wind turbines be more capable of supporting grid frequency. Due to the wind variability, employment of set-point control highly relies on the maximum wind power estimate from forecast data. However, neglecting wake effect of the wind power estimate could lead to overestimation of maximum power, which in turn affects the efficacy of set-point control and miscalculates the wind reserve margin to support system frequency.
Starting from the wind forecast data, this thesis illustrates how the wake effect is applied to correct the wind power estimate. The adjusted wind power forecast is used as a reserve margin reference for set-point control. Following that, the influences of the wake effect on active power control are demonstrated under normal and contingency conditions. Simulation tests conclude the effectiveness of accurate wind power estimation in a realization of set-point control and its contribution to grid frequency.

[1] GWEC, "Global wind report: Annual market update 2015," Global Wind Energy Council, Brussels2016.
[2] WindEurope, "Wind in power: 2014 European statistics," The European Wind Energy Association, Brussels2015.
[3] WindEurope, "Wind in power: 2015 European statistics," The European Wind Energy Association, Brussels2016.
[4] I. Erlich and M. Wilch, "Primary frequency control by wind turbines," presented at the IEEE PES General Meeting, Minneapolis, 2010.
[5] E.on Netz, Grid code: High and extra high voltage, E. O. N. GmbH, 2006.
[6] N. W. Miller and K. Clark, "Advanced controls enable wind plants to provide ancillary services," presented at the IEEE PES General Meeting, Minneapolis, 2010.
[7] Z.-S. Zhang, Y.-Z. Sun, J. Lin, and G.-J. Li, "Coordinated frequency regulation by doubly fed induction generator-based wind power plants," IET Renewable Power Generation, vol. 6, pp. 39-47, January 2012.
[8] J. V. d. Vyver, J. D. M. D. Kooning, T. L. Vandoorn, B. Meersman, and L. Vandevelde, "Comparison of wind turbine power control strategies to provide power reserves," presented at the 2016 IEEE International Energy Conference (ENERGYCON), Leuven, 2016.
[9] M. Singh, V. Gevorgian, E. Muljadi, and E. Ela, "Variable-speed wind power plant operating with reserve power capability," presented at the 2013 IEEE Energy Conversion Congress and Exposition, Denver, CO, 2013.
[10] J. V. d. Vyver, J. D. M. D. Kooning, B. Meersman, T. L. Vandoorn, and L. Vandevelde, "Optimization of constant power control of wind turbines to provide power reserves," presented at the Power Engineering Conference (UPEC), 2013 48th International Universities, Dublin, 2013.
[11] E. Muljadi, M. Singh, and V. Gevorgian, "Fixed-speed and variable-slip wind turbines providing spinning reserves to the grid," presented at the 2013 IEEE Power & Energy Society General Meeting, Vancouver, BC, 2013.
[12] L.-R. Chang-Chien, W.-T. Lin, and Y.-C. Yin, "Enhancing frequency response control by DFIGs in the high wind penetrated power systems," IEEE Transactions on Power Systems, vol. 26, pp. 710-718, 2011.
[13] L.-R. Chang-Chien and Y.-C. Yin, "Strategies for operating wind power in a similar manner of conventional power plant," IEEE Transactions on Energy Conversion, vol. 24, pp. 926 - 934, 2009.
[14] J. Aho, A. Buckspan, J. Laks, P. Fleming, Y. Jeong, F. Dunne, et al., "A tutorial of wind turbine control for supporting grid frequency through active power control," presented at the 2012 American Control Conference (ACC), Montreal, QC, 2012.
[15] A. B. Attya and T. Hartkopf, "Wind turbine contribution in frequency drop mitigation - modified operation and estimating released supportive energy," IET Generation, Transmission & Distribution, vol. 8, pp. 862 - 872, 2014.
[16] K. V. Vidyanandan and N. Senroy, "Primary frequency regulation by deloaded wind turbines using variable droop," IEEE Transactions on Power Systems, vol. 28, pp. 837 - 846, 10 August 2013.
[17] N. Moskalenko, K. Rudion, and A. Orths, "Study of wake effects for offshore wind farm planning," in Modern Electric Power Systems (MEPS), 2010 Proceedings of the International Symposium, Wroclaw, 2010, pp. 1-7.
[18] F. Koch, M. Gresch, F. Shewarega, I. Erlich, and U. Bachmann, "Consideration of wind farm wake effect in power system dynamic simulation," presented at the Power Tech, 2005 IEEE Russia, St. Petersburg, 2005.
[19] M. Gaumond, P.-E. R´ethor´e, A. Bechmann, S. Ott, G. C. Larsen, A. Pe˜na, et al., "Benchmarking of wind turbine wake models in large offshore wind farms," DTU Wind Energy, Denmark2012.
[20] I. Katic, J. Højstrup, and N. O. Jensen, "A simple model for cluster efficiency," presented at the European Wind Energy Conference and Exhibition, Rome, 1986.
[21] N. O. Jensen, "A note on wind generator interaction," Risø National Laboratory, pp. 5-16, 1983.
[22] J. Choi and M. Shan, "Advancement of Jensen (Park) wake model," presented at the EWEA Conference, Wien, 2013.
[23] S. Li, T. A. Haskew, and LingXu, "Conventional and novel control designs for direct driven PMSG wind turbines," Electric Power Systems Research, vol. 80, pp. 328-338, Mar 2010.
[24] M. Ragheb and A. M. Ragheb, Wind turbines theory - The betz equation and optimal rotor tip speed ratio: InTech, 2011.
[25] J.-R. Jhang, "Controllable wind generation system realized by energy storage equipment," Electrical Engineering, National Cheng Kung University, Taiwan, 2010.
[26] K. Tan and S. Islam, "Optimum control strategies in energy conversion of PMSG wind turbine system without mechanical sensors," IEEE Transactions on Energy Conversion, vol. 19, pp. 392 - 399, 2004.
[27] C.-C. Sun, "Wind farm simplified dynamic model and control strategies for variable speed wind turbines," Master, Electrical Engineering, National Cheng Kung University, Taiwan, 2012.
[28] G. Riahy and P. Freere, "Dynamic controller to operate a wind turbine in stall region," in Proceeding of Solar '97, 1997, p. 152.
[29] A. Hwas and R. Katebi, "Wind turbine control using PI pitch angle controller," presented at the IFAC Conference on Advances in PID Control, Brescia (Italy), 2012.
[30] J. Zhang, M. Cheng, Z. Chen, and X. Fu, "Pitch angle control for variable speed wind turbines," presented at the 2008 Third International Conference on Electric Utility Deregulation and Restructuring and Power Technologies, 2008.
[31] Anca Daniela Hansen, "Evaluation of power control with different electrical and control concept of wind farm: Part 2 – Large systems," Technical University of Denmark, Denmark2010.
[32] E. Muljadi and C. P. Butterfield, "Pitch-controlled variable-speed wind turbine generation," presented at the 1999 IEEE Industry Applications Society Annual Meeting, Arizona, 1999.
[33] M. H. Hansen, A. Hansen, T. J. Larsen, S. Øye, P. Sørensen, and P. Fuglsang, "Control design for a pitch-regulated, variable speed wind turbine," Risø National Laboratory, Denmark2005.
[34] W. Gao, Z. Wu, J. Wang, and S. Gu, "A review of inertia and frequency control technologies for variable speed wind turbines," presented at the 2013 25th Chinese Control and Decision Conference (CCDC), Guiyang, 2013.
[35] L. Greedy, "Review of eectrical drive-train topologies," Denmark2007.
[36] H. Saadat, Pwer system analysis. Singapore: McGraw-Hill, 1999.
[37] P. Kundur, Power system stability and control. New York: McGraw-Hill, 1994.
[38] L.-R. Chang-Chien, C.-M. Hung, and Y.-C. Yin, "Dynamic reserve allocation for system contingency by DFIG wind farms," IEEE Transactions on Power Systems, vol. 23, pp. 729 - 736, 2008.
[39] L. J. Vermeer, J. N. Sørensen, and A. Crespo, "Wind turbine wake aerodynamics," Progress in Aerospace Sciences, vol. 39, pp. 467-510, August-October 2003.
[40] M. Ali, J. Matevosyan, J. V. Milanović, and L. Söder, "Effect of wake consideration on estimated cost of wind energy curtailments," 2009.
[41] R. J. Barthelmie, L. Folkerts, G. C. Larsen, K. Rados, S. C. Pryor, S. T. Frandsen, et al., "Comparison of wake model simulations with offshore wind turbine wake profiles measured by sodar," Journal of Atmospheric and Oceanic Technology, vol. 23, 2005.
[42] D. J. Renkema, "Validation of wind turbine wake models: Using wind farm data and wind tunnel measurements," Master, Faculty of Aerospace Engineering, Delft University of Technology, Delft, 2007.
[43] J. Annoni, K. Howard, P. Seiler, and M. Guala, "An experimental investigation on the effect of individual turbine control on wind farm dynamics," Wind Energy, 2015.
[44] A. Crespo, J. Hernández, and S. Frandsen, "Survey of modelling methods for wind turbine wakes and wind farms," Wind Energy, vol. 2, pp. 1-24, 1999.
[45] G. N. Abramovich, The theory of turbulent jets. Cambridge, MA: MIT Press, 1963.
[46] P. B. S. Lissaman, "Energy effectiveness of arbitrary arrays of wind turbines," J. Energy, vol. 3, pp. 323-328, 1979.
[47] S. G. Voutsinas, K. G. Rados, and A. Zervos, "On the analysis of wake effects in wind parks," Journal of Wind Eng Ind Aerodyn, vol. 14, pp. 204–19, 1990.
[48] J. F. Ainslie, "Development of an eddy viscosity model for wind turbine wakes," in 7th BWEA Wind Energy Conference, Oxford, UK, 1985, pp. 61-6.
[49] J. F. Ainslie, "Calculating the flow field in the wake of wind turbines," Journal of Wind Engineering and Industrial Aerodynamics, vol. 27, pp. 213-224, 1988.
[50] E. Luken, A. Talmon, and P. E. J. Vermeulen, "Evaluation of two mathematical wind turbine wake models in various types of flows," 1986.
[51] P. M. Sforza, P. Sheerin, and M. Smorto, "Three-dimensional wakes of simulated wind turbines," AIAA, vol. 19, pp. 1101-1107, 1981.
[52] F. González-Longatt, P. Wall, and V. Terzija, "Wake effect in wind farm performance: Steady-state and dynamic behavior," Renewable Energy, vol. 39, pp. 329-338, March 2012.
[53] S. Grassi, S. Junghans, and M. Raubal, "Assessment of the wake effect on the energy production of onshore wind farms using GIS," Applied Energy, vol. 136, pp. 827-837, 31 December 2014.
[54] P. Nielsen, "WindPRO 2.7 User Guide," in 3. Edition, E. I. A/S, Ed., ed. Denmark: EMD International A/S, 2010.
[55] F. Miceli. (2012). Wind & met mast. Available: http://www.windfarmbop.com/category/met-mast/
[56] Guidelines for converting between various wind averaging periods in tropical cyclone conditions, W. M. Organization, 2008.
[57] W. Gretz, "The wind-measuring mast," vol. 2.07MB, 00215.jpg, Ed., ed: US Department of Energy/NREL, 2012.
[58] L. M. Fernández, J. R. Saenz, and F. Jurado, "Dynamic models of wind farms with fixed speed wind turbines," Renewable Energy, vol. 31, pp. 1203-1230, 2006.
[59] L. M. Fernández, C. A. García, J. R. Saenz, and F. Jurado, "Equivalent models of wind farms by using aggregated wind turbines and equivalent winds," Energy Conversion and Management, vol. 50, pp. 691-704, 2009.
[60] T. G. Corp. (2015). Wind resource assessment. Available: http://www.taiwangenerations.com/english/project.php?projectid=8
[61] W.-Y. Chang, "A literature review of wind forecasting methods," Journal of Power and Energy Engineering, pp. 161-168, 2014.