Analysis of Control Conflict between UPFC Multiple Control Functions and Their Interaction Indicator

  • Wang H. F. (Department of Electronic and Electrical Engineering, the University of Bath) ;
  • Jazaeri M. (School of Electrical Engineering, Semnen University) ;
  • Cao Y. J. (School of Electrical Engineering, Zhejiang University)
  • Published : 2005.06.01

Abstract

Interactions among multiple control functions of a UPFC installed in a power system have been observed in power system simulation and been reported in authors' previous publications [1,2]. This paper presents new analytical results about these observed interactions and concludes that they are due to the control conflict between the series and shunt part of the UPFC, which are connected through the internal common capacitor inside the UPFC. Investigation in the paper reveals, for the first time as far as the authors are aware of, that the linkage pattern of UPFC series and shunt part decides whether the control functions implemented by the UPFC series and shunt part conflict each other or not. This linkage pattern of UPFC series and shunt part can be described by the flow of active power through the UPFC at steady-state operation of the power system. Hence in order to predict the possible interactions among multiple control functions of the UPFC, an interaction indicator is proposed in the paper which is the direction and amount of active power flow through the internal link of the UPFC series and shunt part at steady-state operation of the power system. This proposed interaction indicator can be calculated from power system load flow solution without having to run simulation of the power system with UPFC controllers installed. By using the indicator, the interactions among multiple control functions of the UPFC caused by badly set controller's parameters are excluded. Therefore the indicator only identifies the possible existence of inherent control conflict of the UPFC.

Keywords

References

  1. H. F. Wang, 'Interactions and multi variable design of multiple control functions of a unified power flow controller,' International Journal of Electrical Power and Energy Systems, vol. 24, no. 7,pp. 591-600,2002
  2. H. F. Wang, M. Jazaeri, and A. T. Johns, 'Investigation into the dynamic interactions of multiple multi-functional Unified Power Flow Controllers,' IEEE Power Engineering Letters, vol. 20, no. 7,2000
  3. L. Gyugyi, 'Unified power-flow control concept for flexible AC transmission systems,' IEE Proceedings-C, vol. 139, no. 4, pp. 323-331, July 1992
  4. Y. H. Song and A. T. Johns, Flexible AC Transmission Systems, IEE Press, 1999
  5. M. Noroozian, L. Angquist, M. Ghandhari, and G. Anderson, 'Use of UPFC for optimal power flow control,' IEEE Trans. on Power Delivery, vol. 12, no. 4, pp. 1629-1634, Oct. 1997
  6. M. G. Hingorani and L. Gyugyi, Understanding FACTS, IEEE Press, 1999
  7. A. Nabavi-Niaki and M. R. Iravani, 'Steady state and dynamic models of unified power flow controller (UPFe) for power system studies,' IEEE Trans. on Power System, vol. 11, no. 4, pp. 1937-1943, Nov. 1996
  8. M. Noroozian, L. Angquist, M. Ghandhari, and G. Andersson, 'Use of UPFC for optimal power flow control,' IEEE Trans. on Power Delivery, vol. 12, no. 4, pp. 1629-1634, 1997
  9. D. J. Gotham and G. T. Heydt, 'Power flow control and power flow studies for system with FACTS devices,' IEEE Trans. on Power systems vol. 13, no. 1, pp. 60-65. 1998
  10. D. Z. Fang, Z. Fang, and H. F. Wang, 'Application of the injection modelling approach to power flow analysis for systems with unified power flow controller,' International Journal of Electrical Power & Energy Systems, vol. 23, no. 6, pp. 421-425, 2001
  11. M. Noroozian and G. Andersson, 'Power flow control by use of controllable series components,' IEEE Trans. on Power Delivery, vol. 8, no. 3, pp. 1420-1429, 1993
  12. C. R. Fuerte-Esquivel and E. Acha, 'Unified power flow controller: a critical comparison of Newton-Raphson UPFC algorithms in power flow studies,' IEE Proceedings-C, vol. 144, no. 5, pp. 437-444, 1997
  13. I. Papic, P. Zunko, D. Povh, and M. Weinhold, 'Basic control of unified power flow controller,' IEEE Trans. on Power Systems, vol. 12, no. 4, pp. 1734-1739, 1997
  14. K. S. Smith, L. Ran, and J. Penman, 'Dynamic modelling of a unified power flow controller,' IEE Proceedings-C, vol. 144, no. 1, pp. 7-12, 1997
  15. S. Limyingcharoen, U. D. Annakage, and N. C. Pahalawaththa, 'Effects of unified power flow controllers on transient stability,' IEE Proceedings-C. vol. 145, no. 2, pp. 182-188, 1998
  16. H. F. Wang, 'Damping function of unified power flow controller,' IEE Proceedings-C. vol. 146, no. 1, pp. 81-88, 1999
  17. H. F. Wang, "Applications of modelling UPFC into multi-machine power systems,' IEE Proceedings-C, vol. 146, no. 3, pp. 306-312, 1999