An analytical approach for stochastic assessment of balanced and unbalanced voltage sags in large systems

In this paper, voltage sags produced by balanced and unbalanced short circuits are analyzed by means of a new analytical method. The main feature of this approach is that contrary to the fault positions method, it does not require a preassignation of discrete fault positions along the lines. The developed algorithm has been applied to the 24-buses IEEE Reliability Test System (RTS) and to a real transmission system to illustrate its application. Results are analyzed and compared with the fault positions method. The mathematical formulation of the proposed approach is straightforward and different fault distributions along the lines can be effortlessly considered. The proposed method is adequate for the analysis of any size networks.