Control of CommunicationsDependent Cascading Failures in Power Grids The most severe failures in power grids are often characterized as cascading failures where an initial event triggers consequent failures all along the grid often leading to blackouts. Upon identifying a failure and its cascade potential, timely control actions should be performed by the grid operators to mitigate the effect of the cascade. These actions have to be delivered to one or more control devices, creating a dependency between the power grid and its control network. This paper examines the dependency of the operation of the power grid on the control network. Different from literature studies on failure control, our dependency model captures the impact of networking parameters. We formulate an algorithmic model that describes the impact of this dependency on cascade control. Based on this model, we propose an efficient cascade control algorithm using load shedding with consideration of delays in the communication network for power grids. Finally, we evaluate the impact of the powercommunication network dependency with uncontrolled grids, idealsimple control grids and our proposed control scheme. The results demonstrate that the proposed algorithm can significantly reduce the failure of power lines while sustaining larger power demand for users.

SatisfiabilityBased Analysis of Cascading Failures in Systems of Interdependent Networks This paper proposes a Boolean satisfiability (SAT)based approach to the analysis of cascading failures in systems of interdependent networks. Typical examples of such systems are power systems, where a power transmission network and a SCADA (Supervisory Control And Data Acquisition) network are dependent on each other. The proposed approach reduces the problem of analyzing cascading failures to the SAT problem by constructing Boolean formulas that symbolically represent all possible failure scenarios under given conditions. This allows us to examine a numerous number of scenarios by means of fast modern SAT solvers. The results of experiments show that the proposed approach can deal with practical size systems, such as the IEEE 39 bus system, which ordinary approaches fail to handle.