Document Type : Research paper


Department of Electrical Engineering, National Institute of Technology, Patna, Bihar, India


The voltage stability margin (VSM) is an important indicator to access the voltage stability of the power system. In this paper, Flexible AC transmission systems (FACTS) devices like static synchronous compensator (STATCOM), static synchronous series compensator (SSSC), and unified power flow controller (UPFC) have been deployed to enhance the VSM of the power system. The placement of the FACTS devices is decided based on contingency raking. For the top five critical contingencies, the most severe bus is selected based on bus voltage stability criticality index and degree centrality methods. The critical line is decided based on the values of the line stability index, fast voltage stability index, and line stability factor. The STATCOM and shunt part of the UPFC are placed at the critical bus, whereas the SSSC and series part of the UPFC are placed at the critical line for enhancing voltage stability. The proposed method for voltage stability enhancement using FACTS devices is tested and validated on the IEEE-14 bus system and the NRPG-246 bus system at different system loading scenarios. The impact of the placement of FACTS devices is validated in terms of VSM improvement.


  1. Saadat, “Power systems analysis 2nd edition-psa,” 2009.
  2. W. Taylor, “Voltage stability,” Power System Voltage Stability, pp. 27–32, 1994.
  3. A. Canizares, “Voltage stability assessment: concepts, practices and tools,” IEEE/PES Power System Stability Subcommittee Special Publication, no. SP101PSS, 2002.
  4. Sao, “Voltage stability indicator at the proximity of the voltage collapse point and its implication on margin,” Asian J. Comput. Sci. Inf. Technol., vol. 5, pp. 151–154, 2011.
  5. Hatziargyriou, J. van Hecke, T. van Cutsem, I.C. on Large High Voltage Electric Systems Study Committee Power System Analysis, T.W. G.T. Force, I.C. on Large High Voltage Electric Systems. WG 38/02. Task Force 11, and I.C. on Large High Voltage Electric Systems. Working Group 38.02. Task Force 11, Indices Predicting Voltage Collapse Including Dynamic Phenomena. Brochures thématiques: International Conference on Large High Voltage Electric Systems, CIGRE, 1994.
  6. S. Kundur and O.P. Malik, Power System Stability and Control. McGraw-Hill Education, 2022.
  7. Andersson, P. Donalek, R. Farmer, N. Hatziargyriou, I. Kamwa, P. Kundur, N. Martins, J. Paserba, P. Pourbeik, J. Sanchez-Gasca, et al., “Causes of the 2003 major grid blackouts in north america and europe, and recommended means to improve system dynamic performance,” IEEE Trans. Power Syst., vol. 20, no. 4, pp. 1922–1928, 2005.
  8. Venikov, V. Stroev, V. Idelchick, and V. Tarasov, “Estimation of electrical power system steady-state stability in load flow calculations,” IEEE Trans. Power Appar. Syst., vol. 94, no. 3, pp. 1034–1041, 1975.
  9. -A. Lof, T. Smed, G. Andersson, and D. Hill, “Fast calculation of a voltage stability index,” IEEE Trans. Power Syst., vol. 7, no. 1, pp. 54–64, 1992.
  10. Gao, G. Morison, and P. Kundur, “Voltage stability evaluation using modal analysis,” IEEE Trans. Power Syst., vol. 7, no. 4, pp. 1529–1542, 1992.
  11. Konar, D. Chatterjee, and S. Patra, “V–q sensitivitybased index for assessment of dynamic voltage stability of power systems,” IET Gener. Transm. Distrib., vol. 9, no. 7, pp. 677–685, 2015.
  12. Kessel and H. Glavitsch, “Estimating the voltage stability of a power system,” IEEE Trans. Power Deliv., vol. 1, no. 3, pp. 346–354, 1986.
  13. Musirin and T.A. Rahman, “Novel fast voltage stability index (fvsi) for voltage stability analysis in power transmission system,” in Student conference on research and development, pp. 265–268, IEEE, 2002.
  14. Mohamed, G. Jasmon, and S. Yusoff, “A static voltage collapse indicator using line stability factors,” J. Ind. Technol., vol. 7, no. 1, pp. 73–85, 1989.
  15. Vu, M.M. Begovic, D. Novosel, and M.M. Saha, “Use of local measurements to estimate voltage-stability margin,” IEEE Trans. Power Syst., vol. 14, no. 3, pp. 1029–1035, 1999.
  16. Sagara, R. Shigenobu, O.B. Adewuyi, A. Yona, T. Senjyu, M.S.S. Danish, and T. Funabashi, “Voltage stability improvement by demand response,” in TENCON 2017-2017 IEEE Region 10 Conference, pp. 2144–2149, IEEE, 2017.
  17. M. Hur Rizvi, P. Kundu, and A.K. Srivastava, “Hybrid voltage stability and security assessment using synchrophasors with consideration of generator q-limits,” IET Gener. Transm. Distrib., vol. 14, no. 19, pp. 4042–4051, 2020.
  18. Mohammadniaei, F. Namdari, and M. Shahkarami, “A fast voltage collapse detection and prevention based on wide area monitoring and control,” J J. Oper. Autom. Power Eng., vol. 8, no. 3, pp. 209–219, 2020.
  19. Akbarzadeh Aghdam and H. Khoshkhoo, “Voltage stability assessment algorithm to predict power system loadability margin,” IET Gener. Transm. Distrib., vol. 14, no. 10, pp. 1816–1828, 2020.
  20. Alshareef, R. Shah, N. Mithulananthan, and S. Alzahrani, “A new global index for short term voltage stability assessment,” IEEE Access, vol. 9, pp. 36114–36124, 2021.
  21. Ismail, N.I.A. Wahab, M.L. Othman, M.A.M. Radzi, K.N. Vijayakumar, M.K. Rahmat, and M.N.M. Naain, “New line voltage stability index (bvsi) for voltage stability assessment in power system: the comparative studies,” IEEE Access, vol. 10, pp. 103906–103931, 2022.
  22. Wang, A. Scaglione, and R.J. Thomas, “Electrical centrality measures for electric power grid vulnerability analysis,” in 49th IEEE conference on decision and control (CDC), pp. 5792–5797, IEEE, 2010.
  23. P.R. Coelho, M.H.M. Paiva, M.E.V. Segatto, and G. Caporossi, “A new approach for contingency analysis based on centrality measures,” IEEE Syst. J., vol. 13, no. 2, pp. 1915–1923, 2018.
  24. Hussian, G.R. Goyal, A.K. Arya, and B.P. Soni, “Contingency ranking for voltage stability in power system,” in 2021 IEEE International Conference on Electronics, Computing and Communication Technologies (CONECCT), pp. 1–4, IEEE, 2021.
  25. G. Werkie and H.A. Kefale, “Optimal allocation of multiple distributed generation units in power distribution networks for voltage profile improvement and power losses minimization,” Cogent Eng., vol. 9, no. 1, p. 2091668, 2022.
  26. Kazeminejad, M. Banejad, U. Annakkage, and N. Hosseinzadeh, “The effect of high penetration level of distributed generation sources on voltage stability analysis in unbalanced distribution systems considering load model,” J. Oper. Autom. Power Eng., vol. 7, no. 2, pp. 196–205, 2019.
  27. Gerbex, R. Cherkaoui, and A.J. Germond, “Optimal location of multi-type facts devices in a power system by means of genetic algorithms,” IEEE Trans. Power Syst., vol. 16, no. 3, pp. 537–544, 2001.
  28. G. Hingorani and L. Gyugyi, Understanding FACTS: concepts and technology of flexible AC transmission systems. Wiley-IEEE Press, 2000.
  29. -C. Chang, “Multi-objective optimal svc installation for power system loading margin improvement,” IEEE Trans. Power Syst., vol. 27, no. 2, pp. 984–992, 2011.
  30. -Y. Lee, S.-H. Tsai, and Y.-K. Wu, “A new approach to the assessment of steady-state voltage stability margins using the p–q–v curve,” Int. J. Electr. Power Energy Syst., vol. 32, no. 10, pp. 1091–1098, 2010.
  31. Kumar, B. Tyagi, V. Kumar, and S. Chohan, “Optimization of phasor measurement units placement under contingency using reliability of network components,” IEEE Trans. Instrum. Meas., vol. 69, no. 12, pp. 9893–9906, 2020.
  32. S. Wibowo, N. Yorino, M. Eghbal, Y. Zoka, and Y. Sasaki, “Facts devices allocation with control coordination considering congestion relief and voltage stability,” IEEE Trans. Power Syst., vol. 26, no. 4, pp. 2302–2310, 2011.
  33. Sode-Yome, N. Mithulananthan, and K.Y. Lee, “Comprehensive comparison of facts devices for exclusive loadability enhancement,” IEEJ Trans. Electr. Electron. Eng., vol. 8, no. 1, pp. 7–18, 2013.
  34. P. Roselyn, D. Devaraj, and S.S. Dash, “Multi-objective genetic algorithm for voltage stability enhancement using rescheduling and facts devices,” Ain Shams Eng. J., vol. 5, no. 3, pp. 789–801, 2014.
  35. B. Adetokun, C.M. Muriithi, and J.O. Ojo, “Voltage stability assessment and enhancement of power grid with increasing wind energy penetration,” Int. J. Electr. Power Energy Syst., vol. 120, p. 105988, 2020.
  36. Q. Zhou, U.D. Annakkage, and A.D. Rajapakse, “Online monitoring of voltage stability margin using an artificial neural network,” IEEE Trans. Power Syst., vol. 25, no. 3, pp. 1566–1574, 2010.
  37. Zheng, V. Malbasa, and M. Kezunovic, “Regression tree for stability margin prediction using synchrophasor measurements,” IEEE Trans. Power Syst., vol. 28, no. 2, pp. 1978–1987, 2012.
  38. Ajjarapu and C. Christy, “The continuation power flow: a tool for steady state voltage stability analysis,” IEEE Trans. Power Syst., vol. 7, no. 1, pp. 416–423, 1992.
  39. Moghavvemi and F. Omar, “Technique for contingency monitoring and voltage collapse prediction,” IEE P-Gener. Transm. D., vol. 145, no. 6, pp. 634–640, 1998.
  40. Prabhakar and A. Kumar, “Voltage stability boundary and margin enhancement with facts and hvdc,” Int. J. Electr. Power Energy Syst., vol. 82, pp. 429–438, 2016.
  41. Sodhi, S. Srivastava, and S. Singh, “A simple scheme for wide area detection of impending voltage instability,” IEEE Trans. Smart Grid, vol. 3, no. 2, pp. 818–827, 2012.
  42. Ieee 14-bus system, [Available: edu/research/pstca/pf14/pg_tca14bus.htm].
  43. A. Kamarposhti, M. Alinezhad, H. Lesani, and N. Talebi, “Comparison of svc, statcom, tcsc, and upfc controllers for static voltage stability evaluated by continuation power flow method,” in 2008 IEEE Canada Electric Power Conference, pp. 1–8, IEEE, 2008.
  44. Nrpg 246-bus data, [Available: facilities/Research_labs/Power_System/NRPG-DATA.pdf].
  45. Sahu and M. Verma, “Optimal placement of pmus in power system network for voltage stability estimation under contingencies,” in 2017 6th International Conference on Computer Applications In Electrical Engineering-Recent Advances (CERA), pp. 365–370, IEEE, 2017.