Optimal Backup Power Deployment for Communication Network with Interdependent Power Network

Smart grid has a power network with an interdependent communication network. In such a system, a node failure can lead to another failure in its dependent node in the other network. These inter-network failures can occur recursively in a cascading process, resulting in a complete system collapse. Such cascading failure process can be interrupted by providing backup power to communication nodes, so that they can continue operation when the power nodes they depend on have failed. It is costly to install a backup power unit at each communication node. We have used the two-stage percolation theory to determine the system robustness as a function of backup power deployment density and backup power unit capacity. Then, we propose a novel scheme to determine the optimal backup power deployment density and unit capacity, which can minimize the backup power deployment cost without compromising a desired system robustness. Through extensive simulations, we have found that when the probability of initial node failure is below its critical value, the deployment cost may decrease linearly with a smaller network size and may increase exponentially with a higher robustness requirement.