Fault distribution modeling using stochastic bivariate models for prediction of voltage sag in distribution systems

This paper presents a new method on fault distribution modeling for stochastic prediction study of voltage sags in the distribution system. Two-dimensional stochastic models for fault modeling make it possible to obtain the fault performance for the whole system of interest, which helps obtaining not only sag performance at individual locations but also system sag performance through system indices of voltage sag. By using bivariate normal distribution for fault distribution modeling, the paper estimates the influence of model parameters on system voltage sag performance. The paper also develops the modified SARFI_x regarding phase loads that creates better estimation for voltage sag performance for distribution system.