  This paper proposes a co-optimization generation and distribution planning
model in microgrids in which simultaneous investment in generation, i.e.,
distributed generation (DG) and distributed energy storage (DES), and
distribution, i.e., upgrading the existing distribution network, is considered.
The objective of the proposed model is to minimize the microgrid total planning
cost which comprises the investment cost of installed generation assets and
lines, the microgrid operation cost, and the cost of unserved energy. The
microgrid planning solution determines the optimal generation size, location,
and mix, as well as required network upgrade. To consider line flow and voltage
limits, a linearized power flow model is proposed and used, allowing further
application of mixed integer linear programming (MILP) in problem modeling. The
proposed model is applied to the IEEE 33-bus standard test system to
demonstrate the acceptable performance and the effectiveness of the proposed
model.
