 |
Center for Nonlinear Studies |
With the rapid development of power electronics technologies, inverter-dominated microgrids are becoming a viable solution both for stand-alone sites and as a part of already existing distribution systems. However, attempts to manage such microgrids similar to large-scale power systems revealed severe operational constraints on control settings and grid parameters with unexpected instabilities caused even by seemingly trivial configuration changes. Moreover, modelling assumptions that have been in use for decades for conventional power systems proved to be unjustified for microgirds giving overly optimistic predictions of their performance. In our recent work we have proposed a method of effective model order reduction, based on singular perturbation expansion, introducing the, so-called, transient admittance matrix. This allowed uncovering the unique dynamic properties of microgrids, having no analogy in conventional power systems and explaining the reasons for significant stability constraints present in microgrids. Moreover, we have established that most of the standard methods for stability enhancement employed in conventional power systems have almost the opposite effect when applied to microgrids, indicating the need for development of new methods, specific to microgrids. The subsequent use of quadratic Lyapunov functions allowed us to derive a set of practically applicable fully decentralized stability conditions for microgirds having a broad scope of possible applications. We also discuss the development of plug-and-play architectures through standardization of inverter control settings.
Host: Scott Backhaus