Load frequency control in deregulated power system with wind integrated system using fuzzy controller

Abstract

This paper presents the analysis of load frequency control (LFC) of a deregulated two-area hydro-thermal power system using fuzzy logic controller, with doubly fed induction generators (DFIGs) integrated into both the control areas. The deregulation of power sector has led to the formation of new companies for generation, transmission and distribution of power. The conventional two-area power system is modified to study the effects of the bilateral contracts of companies on the system dynamics. Deregulation creates highly competitive and distributed control environment, and the LFC becomes even more challenging when wind generators are also integrated into the system. The overall inertia of the system reduces, as the wind unit does not provide inertia and isolates from the grid during disturbances. The DFIGs integrated provide inertial support to the system through modified inertial control scheme, and arrests the initial fall in frequency after disturbance. The inertial control responds to frequency deviations, which takes out the kinetic energy of the wind turbine for improving the frequency response of the system. To enhance the participation of the doubly fed induction generator (DFIG) in the frequency control, optimal values of the speed control parameters of the DFIG-based wind turbine have been obtained using integral square error (ISE) technique. The dynamics of the system have been obtained for a small load perturbation, and for contract violation using fuzzy controller.

Keywords

frequency regulation / fuzzy controller / de-regulated power system / doubly fed induction generator (DFIG) / bilateral contract

References

[1] Christie R D, Bose R. Load frequency control issues in power system operations after deregulation. IEEE Transactions on Power Systems, 1996, 11(3): 1191–1200

[2] Donde V, Pai M A, Hiskens I A. Simulation and optimization in AGC system after deregulation. IEEE Transactions on Power Systems, 2001, 16(3): 481–489

[3] Keung P, Lei P, Banakar H, Ooi B T. Kinetic energy of wind-turbine generators for system frequency support. IEEE Transactions on Power Systems, 2009, 24(1): 279–287

[4] Xue Y C, Tai N L. Review of contribution to frequency control through variable speed wind turbine. Renewable Energy, 2011, 36(6): 1671–1677

[5] de Almeida R G, Lopes J A P. Participation of doubly fed induction wind generators in system frequency regulation. IEEE Transactions on Power Systems, 2007, 22(3): 944–950

[6] Verma Y P, Kumar A. Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation. Frontier in Energy, 2012, 6(2): 184–192

[7] Mauricio J M, Marano A, Gómez-Expósito A, Ramos J L M. Frequency regulation contribution through variable-speed wind energy conversion systems. IEEE Transactions on Power Systems, 2009, 24(1): 173–180

[8] Kayikci M, Milanovic J V. Dynamic contribution of DFIG-based wind plants to system frequency disturbances. IEEE Transactions on Power Systems, 2009, 24(2): 859–867

[9] Raju P S, Farook S. AGC controllers to optimize LFC regulation in deregulated power system. International Journal of Advances in Engineering and Technology, 2011, 1(5): 278–289

[10] Rao C S, Nagaraju S S, Raju P S. Automatic generation control of TCPS based hydrothermal system under open scenario: A fuzzy logic approach. Electrical Power and Energy Systems, 2009, 31(7,8): 315–322

[11] Bhatt P, Roy R, Ghoshal S P. Load frequency control of interconnected restructured power system along with DFIG and coordinated operation of TCPS-SMES. In: Proceedings of 2010 Joint International Conference on Power Electronics, Drives and Energy Systems (PEDES) & 2010 Power India. New Delhi, India, 2010, 131–136

[12] Chown G A, Hartman R C. Design and experience with a fuzzy logic controller for automatic generation control. In: Proceedings of 20th International Conference on Power Industry Computer Applications. Columbus, USA, 1997, 352-357

[13] Fathima A P, Khan M A. Design of a new market structure and robust controller for the frequency regulation services in the deregulated power system. Electrical Power Components and Systems, 2008, 36(8): 864–883

[14] Verma Y P, Kumar A. Participation of DFIG based wind turbine in frequency regulation with frequency linked pricing. Electrical Power Components and Systems, 2012, 40(14): 1586–1604

[15] Morren J, Haan S W H, Kling W H, Ferreira J A. Wind turbines emulating inertia and supporting primary frequency control. IEEE Transactions on Power Systems, 2006, 21(1): 433–434

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Higher Education Press and Springer-Verlag Berlin Heidelberg