Modeling of Cascading Failures in Cyber-Coupled Power Systems

In this paper, we develop a stochastic model from the perspective of complex networks to investigate the effects of cyber coupling on cascading failures in coupled power systems. The failure spreading in the coupled system is described by state transition and modeled as a Markov process. We simulate the dynamic profile of the cascading failures caused by the attack of cyber malwares, considering the effects of power overloading, contagion and interdependence between power grids and cyber networks. We study the coupled system created by coupling the UIUC 150 Bus System with synthesized scale-free cyber network. Simulation results present that the dynamic profile of the cascading failures in a coupled system displays a "staircase-like" pattern which can be interpreted as a combined feature of the typical step propagation profile triggered repeatedly by cyber attacks due to cyber network coupling. Results also show that cyber coupling can intensify both the extent and rapidity of power blackouts. Moreover, adopting assortative coupling patten accelerates the failures propagation, in particular under highdegree cyber node targeted attack.