POWER-SYSTEM VOLTAGE STABILITY AND SECURITY ASSESSMENT

The purpose of this investigation is to review the recent research pro gress in voltage stability and security assessment of power systems. T his paper presents the fundamental concepts of voltage stability, give s a short recall of the classical voltage theory and different criteri a currently available for predicting voltage collapse problems in powe r systems, which have been associated with multiple power flow solutio ns, bifurcation, dynamics of tap changers, stochastic loads, singular values, etc. The various methods for studying voltage collapse are com pared. The application of expert system techniques to assist in the de cision-making process of the reactive power/voltage control problem of power systems and future research directions towards voltage stabilit y and security assessment will also be proposed in this paper.