Stability of inverter-interfaced power systems with multi-scale-free properties

Abstract

Scale-free networks are proven to have many distinct properties and numerous statistical studies have shown that most large power systems have the scale-free topology. However, the overall system behavior is also constrained by node dynamics, of which the interaction effects with network topology remain unknown. Here, we investigate the individual and mutual effects of network degree distribution, with two system dynamic parameters, on system small-disturbance angle stability. We show that network degree distribution and active power injection distribution are critical in determining system small-disturbance angle stability while frequency coefficient shows relatively less significant influence. Further, the scale-free level for degree distribution positively interacts with active power injection distribution on the overall system behavior. Consequently, not only network topology but also system dynamic parameters and, importantly, their synergistic effects matter in determining system behavior. Based on the results, we further provide guidance for the coordination of the various parameters to improve system small-disturbance angle stability.