Stochastic prediction of voltage sags by considering the probability of the failure of the protection system

This paper presents a comprehensive method for stochastic prediction of the number and characteristics of voltage sags in large distribution networks. The novelty of the proposed approach is in probabilistic modeling of the failure of the protection system. The probability of the failure of the protection system is determined using a straightforward, decision tree based method. The paper highlights the effects of the protection system failure on the number and characteristics of voltage sags. The method proposed and its capabilities are demonstrated on the realistic size generic distribution system. The results presented in the paper show that the proposed method is superior to the traditional techniques used for the assessment of voltage sags as it results in higher accuracy of the prediction of the number and characteristics of voltage sags.