Toward standards for model-based control of dynamic interactions in large electric power grids

This paper is motivated by the recent needs to manage possible instabilities between electrically-connected system components and/or sub-systems (layers) in future electric energy systems. It is shown that standard state-space models of general multi-layered energy systems have fundamentally the same structure which can be expressed in terms of: 1) state variables representing stand-alone layer (sub-system) dynamics; and, 2) an interaction variable between the layer and the rest of the system. Once this is recognized, three possible structure-based control designs are derived and analyzed for their performance using a small power system model. The three control designs considered are: 1) a decentralized component (generator)-level output controller; 2) a decentralized sub-system (control area) layer output controller; and, 3) a full-state centralized system-level controller. Pros and cons of these three control architectures and their implications on three qualitatively different IT architectures and standards for dynamics in future electric energy systems are discussed.