  This work provides a design method for achieving a specified level of
stability for inverter-based interconnected distributed generation. The
stability of parallel connected distributed energy resources determined from a
linearized state-space model of the inverter dynamics that includes the
admittance matrix of the interconnecting distribution lines. Each inverter uses
a localized droop control scheme with the associated voltage and frequency
measurements obtained through the application of an enhanced phase locked loop.
Previous work on this topic has focused on single inverters connected to an
infinite bus without modeling of delays from a phase locked loop
implementation. This proposed method overcomes both of these limitations of
previous research. A detailed large-signal simulation of a three-bus
interconnected power system is analyzed under two different network admittance
values. Results confirm the effectiveness of the proposed stability design
method.
