Voltage stability – Case study of saddle node bifurcation with stochastic load dynamics

► We provide a better way of understanding voltage stability in power system. ► We examine the effect of stochastic models of the load on the SMIB power system. ► We evaluate Mean First Passage Time (MFPT) of SMIB system for various random load variation. This paper presents an approach of analyzing power system voltage stability based on system potential. This framework provides a simple and better way of understanding voltage stability by visualizing the changes in topological structure of the system potential with respect to the change in power system loading. This paper also investigates the effect of random load variation in the power system stability. The stability margin index being studied is the Mean First Passage Time of the power system from the stable operating point to the closest unstable equilibrium point for small magnitude random load perturbations. The variation of MFPT for change in the loading of the system, Intensity and correlation time of the stochastic load are studied initially for an SMIB system.