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.

Analysis and Design of Three-Level, 24-Pulse Double Bridge Voltage Source Converter Based HVDC System for Active and Reactive Power Control


This paper manages the investigation, plan and control of a three-level 24-beat Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) framework. A three dimension VSC working at essential recurrence exchanging (FFS) is proposed with 24-heartbeat VSC structure to enhance the power quality and decrease the converter exchanging misfortunes for high influence applications. The structure of three-level VSC converter and framework parameters, for example, air conditioning inductor and dc capacitor is displayed for the proposed VSC based HVDC framework. It comprises of two converter stations encouraged from two diverse air conditioning frameworks. The dynamic power is exchanged between the stations in any case. The receptive power is autonomously controlled in every converter station. The three-level VSC is worked at advanced dead edge (β). A planned control calculation for both the rectifier and an inverter stations for bidirectional dynamic power stream is created dependent on FFS and neighborhood responsive power age. This outcomes in a significant decrease in exchanging misfortunes and maintaining a strategic distance from the responsive influence plant. Recreation is conveyed to confirm the execution of the proposed control calculation of the VSC based HVDC framework for bidirectional dynamic power stream and their autonomous receptive power control.



Fig. 1 Three-level 24-pulse double bridge VSC based HVDC system




Fig. 2a Performance of rectifier station during reactive power control of three level 24-pulse VSC HVDC system


Fig. 2b Performance of Inverter station during reactive power control at rectifier station of three-level 24 pulse VSC HVDC system


Fig. 2c Variation of (δ) and (α) values for rectifier and inverter Stations for reactive power variation of a three-level 24-pulse VSC HVDC system


Fig. 3a Rectifier station during active power reversal of three-level 24-pulse VSC HVDC system


Fig. 3b Inverter station during active power reversal of three-level 24-pulse VSC HVDC system


Fig. 3c Variation of (δ) and (α) values during active power reversal of three level 24-pulse VSC HVDC system.


Another three-level, 24-beat voltage source converter based HVDC framework working at essential recurrence exchanging has been planned and its model has been produced and it is effectively tried for the autonomous control of dynamic and receptive forces and satisfactory dimension consonant prerequisites. The responsive power has been controlled free of the dynamic power at the two conditions. The converter has been effectively worked in each of the four quadrants of dynamic and responsive forces with the proposed control. The inversion of the dynamic power stream has been actualized by switching the course of dc current without changing the extremity of dc voltage which is exceptionally troublesome in traditional HVDC frameworks. The power nature of the HVDC framework has additionally enhanced with three-level 24-beat converter task. The symphonious execution of this three-level, 24-beat VSC has been seen to an identical to two-level 48-beat voltage source converter.