Analysis of voltage sags propagation in distribution grids using a SI epidemic model

The occurrence of different types of faults and connection of heavy loads could cause voltage sags in several busbars in distribution grids. In this paper a Susceptible-Infected (SI) epidemic model is proposed to assess the propagation of voltage sags in distribution systems. In the SI model, the infectious nodes are the bus-bars where faults or connection of big loads could occur. On the other hand, susceptible nodes are the bus-bars in which voltage sags could occur. Parameters that affect the voltage sags propagation as system topology and detection threshold are modeled using the concept of infection rate (β). + A directed graph representing the voltage sags propagation is calculated based on the values of β between every pair of nodes. Finally, the propagation is characterized in terms of fault impedance and nodes are classified using graph theory indexes.