Assessing the topological structure of a smart low-voltage grid

The electric power grid is a critical infrastructure that delivers electric power from electricity sources to consumers. Currently, renewable and distributed sources of electricity, as well as new technologies that introduce large loads, are significantly changing the load profiles at the low-voltage grid. This trend calls for reassessing the structure of the low-voltage grid to see if it can safely accommodate the new load profiles. Moreover, the future smart grid relies on ICT (Information and Communication Technology) networks to support decentralized power distribution. Yet, the nodes of the ICT networks might depend on the grid itself for power supply leading to bidirectional interdependence between the two networks, which might affect the reliability of the power grid. The focus of this paper is to enhance the reliability of the future lowvoltage grid, by improving the structure of the low-voltage grid itself as well as by identifying its interdependence with the ICT network. We investigate the structural features of the low-voltage grid and assess their influence on its capability to handle the new load profiles. We use concepts from complex networks theory to derive relevant structural metrics that characterize the structural properties of the low-voltage grid. We also propose performance metrics that reflect the operational performance of the low-voltage grid. We analyze different low-voltage networks under various loading scenarios to observe the influence of structural metrics of the low-voltage grid on its operational metrics. Based on this analysis, we propose a constraint programming formulation for cost-optimal and robust design of the struc∗The corresponding author is Fernando Kuipers Email addresses: [email protected] (Ebisa Negeri), [email protected] (Fernando Kuipers), [email protected] (Nico Baken) Preprint submitted to Critical Infrastructures Protection December 15, 2014 ture of the low-voltage grid. In addition, based on our assessment of the interdependence level between the ICT and low-voltage networks, we propose a design algorithm for the dependency of ICT nodes on grid nodes to increase the reliability of the grid.