Voltage stability and robustness for microgrid systems

Voltage stability is of essential importance for power grids. The emergence of distributed energy generators, controllable loads, and local-area energy storage capabilities have introduced new scenarios for distribution networks in which classical frameworks for voltage stability may be inadequate. This paper introduces a control-theoretic framework for studying voltage stability and its robustness, as well as optimal power management in distribution systems composed of networked microgrids. The framework involves descriptions of the loads and generators by nonlinear state space models and the network connections by a set of topology-based algebraic equations. The integration of the combined system leads to a general nonlinear state space model for the microgrid systems. Simplified microgrids are used to illustrate the concepts.