Voltage stability assessment in the deregulated electricity markets

With the deregulation of electricity markets, the system operation strategies have changed in recent years. The systems are operated with smaller margins. How to maintain the voltage stability of the power system has become an important issue. This paper presents the voltage stability assessment with the consideration of uneven regional load growth pattern and economic dispatch of the online generation units, aiming at assessing the voltage stability margin of a power system for a given operating condition and network topology in more realistic manner. The proposed method is tested on the 6-bus system from Wood & Wollenberg and IEEE 118-bus system with promising results.