Stability Analysis of Distributed Power Generation with Droop Inverters

This paper models and analyzes a power distribution system with sources connected through inverters. The stabilizing effect of generator rotational inertia is emulated through inverter droop control logic. We model the nonlinear dynamics of the system with multiple distributed droop inverters using dynamical phasors. Linearizing the system around the steady-state we construct closed-loop transfer functions from exogenous disturbances to system states. This allows to evaluate the load disturbance impact on the inverter power and line voltage profile. As an example, the distribution system with 150 inverters is used to illustrate the approach.