On the number of system separations in power system

Power systems subjected to large disturbances may become transiently unstable, which can lead to uncontrolled system separation and cascading outages. An important goal of developing the smart grids is to maintain high-level system stability. Controlled islanding is a corrective measure that can efficiently attenuate the detrimental impact of large disturbances by splitting the system into self-healing islands. This paper is devoted to a quantitative study of unstable equilibrium points on the stability boundary, which gives an estimate for the number of possible system separations and provides useful guideline for the strategy design of controlled islanding.