On the use of cyber-physical hierarchy for smart grid security and efficient control
2012 25th IEEE Canadian Conference on Electrical and Computer Engineering (CCECE)
We study the application of cyber-physical hierarchy on a class of smart grid systems to improve scalability. Our framework employs a multi-agent flocking-based approach to study the transient stability problem in emerging power systems. An agent in this context embodies a coherent group of system generators. We demonstrate how our paradigm conveniently facilitates the identification of coherent machine clusters through spectral bisection of the associated Kronreduced power system graph. This
... ables a state-dependent system hierarchy whereby inter-agent interactions are cyber-physical (tier-1) and intra-agent synergies are physical (tier-2). By leveraging this layered perspective, active control can be employed only at a select "lead" generator of each agent; secondary generators that are necessarily coherent to a lead generator will naturally follow suit. Thus this cyber-physical hierarchy improves communications and energy overhead by introducing cyber couplings only within components of the smart grid where physical relationships are insufficient for transient stability in the face of a incidental fault or intentional attack. We demonstrate the performance of our approach on the 9-bus WECC system demonstrating its lower overhead and greater robustness to cyber attacks resulting in information delay. Index Termscyber-physical system security, smart grid hierarchy, flocking theory.