An analytical approach for stochastic assessment of voltage sags in distribution systems

In this paper, analytical expressions for the calculation of voltage sag magnitude due to faults along the line of distribution system are derived. The theoretical background about the residual voltages due to balanced and unbalanced faults at the bus and along the line is presented. A method is described to calculate the number of voltage sags per year. This analytical method is applied for the voltage sag assessment of a real Indian distribution system.