Abstract
In modern power systems voltage instability is a serious issue with rapid voltage droop due to stressed system with increased loading. Voltage collapse can be predicted and voltage stability of power system can be maintained by many techniques. Voltage stability index (VSI)is one such technique used for solving voltage stability issues. In this paper, a new index is proposed and comparison of this new index performance with the other indices is discussed. The effectiveness of the proposed method is demonstrated through numerical studies on Practical 72 bus system of Southern grid in India, using several scenarios of increase in load. The process known as continuation load flow is used.The proposed voltage stability index considers the nose point voltage and the present bus voltage level and the difference of the two at the point where the jacobian matrix becomes a singular matrix for the equal load conditions. In case of contingencies, chances of system voltage collapse are high. All these cases are analyzed in the paper.
Key Words: - voltage stability, voltage stability index, critical point.
References
1. P.Kundur “Power System Stability and Control” McGraw-Hill, New York, 1994
2. “Voltage Stability of Power Systems: Concepts, Analytical Tools and Industry Experience”, IEEE Committee Vol.IEEE/PES 93TH0358-2- PWR 1990.
3. K. Takahashi and Y. Nomura “The Power System Failure on July 23rd 1987 in Tokyo” CIGRE SC-37 Meeting 37.87(JP) 07(E) 1987.
4. J.C. Chow, R. Fischl and H. Yan “On the Evaluation of Voltage Collapse Criteria” IEEE Trans., PWRS-5, pp. 612-620, May 1990
5. P.Kessel, H.Glavitsch “Estimating the Voltage Stability of a Power System” IEEE, Transactions on Power Delivery, Vol.PWRD-1, N3, July 1986