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Wednesday, 19 July 2017

Performance of Distributed Power Flow Controller on System Behavior under Unbalance Fault Condition

Recently, within the family of FACTS, the distributed power flow controller is an additional device. This paper highlights on voltage sag mitigation which is one of the burgeoning power quality issues. It deals with the working concept of distributed power flow controller for compensating unbalanced three phase line currents in the transmission system. The single phase series converters of DPFC are able to compensate active as well as reactive, negative and zero sequence unbalanced currents. In this paper the performance of the DPFC has been studied by considering line to ground fault near the load end. The MATLAB/SIMULINK results obtained shows an improved performance in voltage sag mitigation, unbalance compensation, remarkable reduction in load voltage harmonics and also enhanced power flow control.

1.      DPFC
2.      Power flow control
3.      Reduction of load voltage harmonics
4.      Reliability improvement
5.      Voltage sag mitigation
6.      Unbalance fault condition.



Fig. 1. Basic DPFC structure.


Fig. 2. Load voltage sag waveform during unbalance fault.

Fig. 3. Mitigation of load voltage sag wave form during unbalance fault with DPFC.

Fig. 4. Load voltage. (a) Signal selected for calculating THD without DPFC. (b) THD without DPFC.

Fig. 5. Load voltage. (a) Signal selected for calculating THD with DPFC. (b) THD with DPFC.

Fig. 6. Capacitor dc voltage in dc side of shunt converter within DPFC.

This paper introduces the unbalance compensation and the voltage sag mitigation during unbalance fault condition by utilizing a recent additional FACTS device which is distributed power flow controller (DPFC) adopting sequence analysis technique. The DPFC is designed by employing three control loops. The simulated system has two machine systems, in presence and absence of the DPFC in the system. To examine the capability of the DPFC, an unsymmetrical L-G fault is taken into account near the load end side. In this paper simulation done verifies that the adopted control is able to give unbalance compensation and mitigation of voltage sag.

[1]   N. G. Hingorani and L. Gyugyi, Understanding FACTS : Concepts And Technology of Flexible AC Transmission Systems. New York: IEEE Press, 2000.
[2]   L. Gyugyi, C. D. Schauder, S. L. Williams, T. R. Rietman, D. R. Torgerson, and A. Edris, “The Unified Power Flow Controller: A New Approach to Power Transmission Control,” IEEE Trans. Power Del., vol. 10, no. 2, pp. 1085–1097, April 1995.
[3]    Y. H. Song, and A. Johns, “Flexible AC Transmission Systems (FACTS),” Institution of Electrical Engineers (IEE Power and Energy Series), London, U.K:, vol. 30, 1999.
[4]    K. Ramya and C. Christober Asir Rajan, “Analysis And Regulation of System Parameters Using DPFC,” IEEE International Conference on Advances in Engineering, Science And Management (ICAESM), March 2012, pp. 505-509.

[5]   M. D. Deepak, E. B. William, S. S. Robert, K. Bill, W. G. Randal, T. B. Dale, R. I. Michael, and S. G. Ian, “A Distributed Static Series Compensator System For Realizing Active Power Flow Control on Existing Power Lines,” IEEE Trans. Power Del., vol. 22, pp. 642-649, Jan. 2007.