Simulation of SMIB power system with stochastic load

This paper presents an method of simulating the Single Machine Connected to Infinite Bus (SMIB) power system with load modeled as the random quantity. This paper investigates the effect of random load variation in the power system stability. The stability margin index being studied is the Mean First Passage Time (MFPT) 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 and damping of the system, Intensity and correlation time of the stochastic load are studied. The theoritical expression used for calculation for calculation of the MFPT in (Qui and Shahidehpour, 1989) is shown to have limitations for calculations of MFPT for systems with less energy barrier and wide ranges of damping.