Resilience of urban smart grids involving multiple control loops

Abstract

Intelligent control of energy distribution grids is implemented via a hierarchy of control loops with different input values and different control targets, which also work on different time-scales. This control is enabled by a bi-directional communication flow, which can be interrupted due to ICT attacks. It is therefore necessary to analyze and understand the emergent behavior resulting from the interplay of the different control loops and how this behavior may change under different communication scenarios. The simulation scenario considered in this paper is a medium and low voltage grid in island mode with a limited grid buffer capacity subjected to ICT attacks. First the interplay of four different control loops that all react to time-varying prices is analyzed. A co-simulation framework is applied to specifically investigate the sensitivity of the emergent grid behavior to extreme conditions on the the price signal communication which could be the result of ICT attacks. In a second step, we introduce a modified pricing scheme, where the energy price is locally influenced by the distribution grid conditions. We then analyze the behavior of this modified scheme when both up-stream and downstream communication are subject to communication delays and losses resulting from ICT attacks.