Unbalanced voltage sag source location identification based on superimposed quantities and negative sequence

This paper presents a new method to effectively identify the unbalanced sags source location based on negative sequence and superimposed quantities concept. Many previous proposed methods have shown good performance for balanced voltage sag cases. However, their performance reduces for the unbalanced voltage sags, which are the major sag events in power system. The proposed method was derived mathematically and verified by computer simulations and field data from voltage sag survey. The results show the good performance of proposed method. Moreover, the method can locate the sag source in both transmission and radial system.