Disturbance Propagation Stability in Droop-Controlled Microgrids

Abstract

The disturbance response of the angle dynamics for a droop-controlled islanded microgrid is characterized. Specifically, a notion of propagation stability is defined, which is concerned with spatial attenuation vs amplification of input-output responses in the network in a ℋ∞ or ℋ2 sense. Criteria for propagation stability are developed, phrased in terms of the microgrid’s inverter control parameters. The input frequency range over which the network is susceptible to amplification is also characterized, in the case that the criteria are not met. Based on the formal analysis, the design of resilient controls that trade off coherence and disturbance propagation goals is briefly conceptualized. Finally, the propagation stability analysis is illustrated using a 15-bus example microgrid network.