This paper proposes three-phase steady-state models for distributed
generators (DGs) with different control strategies and an augmented
rectangular load flow method is used for three-phase distribution
systems. For two kinds of DGs with power electronic devices:
photovoltaic power generators and doubly-fed induction generators, the
nodal voltage equations and the output power equations are derived.
Moreover, under the unbalanced conditions, the control strategies are
applied and formulated as the function of the nodal voltage and the
injected current to reduce the effects caused by the negative-sequence
components. Furthermore, the models are incorporated into an augmented
rectangular load flow method with nodal voltage and injected current as
state variables in three-phase systems. Case studies are conducted to
verify the correctness and accuracy of the proposed models by comparing
the results obtained from MATLAB and PASCAD.