Stochastic assessment of voltage sags for balanced and unbalanced faults

Abstract

Stochastic assessment is a technique to predict the severity and number of voltage sags at a bus of interest in the transmission and distribution network. In this paper, an analytical technique using secant technique is developed to predict the voltage magnitudes and duration due to balanced and unbalanced faults in unlimited buses in an electrical network. The proposed secant technique is compared with the method of critical distance and fault position method in terms of accuracy and practical application. The proposed technique was applied to an IEEE 24- buses electrical network to illustrate its application. The results show that the proposed technique is able to predict the voltage sag magnitude and duration at any buses and the number of sags per year for both balanced and unbalanced fault. © 2011 Praise Worthy Prize S.r.l. -All rights reserved.