Probabilistic vulnerability assessment based on power flow and voltage distribution

In this paper, a method to evaluate the power system vulnerability in terms of voltage magnitudes and transmission lines passing their limits is presented. Probabilistic technique is applied to obtain the distribution characteristics of the voltage magnitude and transmission line power flows. Cumulant-based expansion method is used to obtain the probabilistic distribution function (PDF) and cumulative distribution function (CDF) of power flows on transmission lines and voltage magnitudes at buses. The index to measure the system vulnerability is developed. The western North American power system model is used in the simulation to demonstrate the effectiveness of the method.