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Frontiers in Energy

Front Energ    2013, Vol. 7 Issue (2) : 245-254
Load frequency control in deregulated power system with wind integrated system using fuzzy controller
Yajvender Pal VERMA1(), Ashwani KUMAR2
1. Department of Electrical & Electronics Engineering, UIET, Panjab University, Chandigarh 160014, India; 2. Department of Electrical Engineering, National Institute of Technology Kurukshetra, Haryana 132119, India
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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     
Corresponding Authors: VERMA Yajvender Pal,   
Issue Date: 05 June 2013
 Cite this article:   
Yajvender Pal VERMA,Ashwani KUMAR. Load frequency control in deregulated power system with wind integrated system using fuzzy controller[J]. Front Energ, 2013, 7(2): 245-254.
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Yajvender Pal VERMA
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Fig.1  Two-area hydro-thermal system for deregulated market with DFIG integrated
Fig.2  DFIG-based wind turbine control based on frequency change
Tab.1  Fuzzy rules for two-area system
Fig.3  Fuzzy logic controller
Fig.4  Frequency response of area-1 and area-2 with and without DFIG
With DFIGWithout DFIG
Delta F1US-0.0976-0.1082
Delta F2US-0.0607-0.07284
Performance index J7.18 × 10-38.58×10-3
Tab.2  US and OS and performance index of frequency responses with and without DFIG
Fig.5  Generation of Gencos
(a) Thermal; (b) hydro area
Fig.6  eneration response and speed variations of DFIG in area-1 and area-2 for a load change of 2% in area-1
(a) Generation of DFIGs; (b) rotor speed variations with 2% load change in area-1
Fig.7  Tie-line power flow for load perturbation in area-1
Fig.8  ACEs with and without DFIG
(a) Area-1; (b) area-2
Fig.9  Generation of Gencos
(a) and (b) Hydro units; (c) and (d) thermal units
Fig.10  Frequency responses of areas during contract violation
(a) Area-1; (b) area-2
Fig.11  Comparison of performance index with and without DFIG
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