Effects of Tap Changing Transformer and Shunt Capacitor on Voltage Stability Enhancement of Transmission Networks

Voltage stability has become an important issue to many power systems around the world due to the weak systems and long line on power system networks. In this paper, MATLAB load flow program is applied to obtain the weak points in the system combined with finding the voltage stability limit. The maximum permissible loading of a system, within the voltage stability limit, is usually determined. The methods for varying tap ratio (using tap changing transformer) and applying different values of shunt capacitor injection to improve the voltage stability within the limit are also provided.

• Pyone Lai Swe
• Wanna Swe
• Kyaw Myo Lin

• Load flow
• Voltage stability
• Tap changingtransformer
• Shunt capacitor injection
• Voltage stability limit

[1] Chakrabarti and S. Halder, "Power System Analysis: Operation and
Control," 2nd Edition, PHI Learning Private Ltd, 2008.
[2] I. Musirin, T.K.A. Rahman "Novel Fast Voltage Stability Index
(FVSI) for Voltage Stability Analysis in Power Transmission
System" 2002 Student Conference on Research and Development
Proceedings, Shah Alam, Malasia, July 2002.
[3] J. Kubokuwa, R. Inoue and H. Sasaki, "A Solution of Optimal Power
Flow with Voltage Stability Constraints", Proc International
Conference of Power Systems Technology - PowerCon, Vol. 2, 2000,
pp. 625 - 630.
[4] Hadi Saadat, "Power System Analysis," McGraw-Hill
Inc,International Editions, 1999.
[5] T. Van Cutsem and C. Vournas, Voltage Stability of Electric Power
Systems: Kluwer Academic Publishers, 1998.
[6] D. Thukaram, K. Parthasarathy, H. P. Khincha, N. Udupa and A.
Bansilal, "Voltage Stability Improvement: Case Studies of Indian
Power Network", Electric Power Systems Research, Vol. 44, No. 1,
January 1998, pp. 35 - 44.
[7] P. Kundur: "Power System Stability and Control," New York:
McGraw-Hill, 1994.
[8] Y. Tamuraet.al., "Relationship between voltage instability and
multiple load flow solutions in electric power systems" IEEE Trans.
on Power Systems. Vol PAS - 102, No.5, pp.1115-1125, May 1993.
[9] P.W. Sauer, R.J. Evans, and M.A. Pai, "Maximum unconstrained
loadability of power systems," IEEE Int. Symp. Circuits and Systems
1990, vol. 3, pp. 1818-1821.