Economic Dispatch and Power Flow Analysis for Microgrids
Saskia A. Putri, Xiaoyu Ge, Javad Khazaei
TL;DR
The paper addresses economic dispatch and optimal power flow for two microgrid configurations—an islanded single-bus MG and a grid-tied three-bus MG—using renewables, BESS, and conventional generators to minimize cost while meeting load. It proposes a mixed-integer nonlinear programming framework implemented in MATLAB (Currie_OPTI) to optimize generation, storage, and grid exchange over daily and weekly horizons, incorporating dynamic electricity pricing. Key findings show extensive renewable use, strategic BESS operation to balance intermittency, and that Bus 1 often supplies the largest share due to its lower-cost resource mix; voltage deviations remain within acceptable bounds but call for a secondary voltage-control layer. The work demonstrates a practical, reproducible approach to sustainable, cost-effective, and stable microgrid operation, with public access to the source code.
Abstract
This study investigates the economic dispatch and optimal power flow (OPF) for microgrids, focusing on two configurations: a single-bus islanded microgrid and a three-bus grid-tied microgrid. The methodologies integrate renewable energy sources (solar PV and wind turbines), battery energy storage systems (BESS), and conventional generators (CHP, diesel, and natural gas), which are connected to the grid to ensure cost-efficient and reliable operation. The economic dispatch analysis evaluates the allocation of generation resources over daily and weekly horizons, highlighting the extensive utilization of renewable energy and the strategic use of BESS to balance system dynamics. The OPF analysis examines the distribution of active and reactive power across buses while ensuring voltage stability and compliance with operational constraints. Results show that the microgrid consistently satisfies load demand with minimal reliance on costly external grid power. Renewable energy sources are maximized for cost reduction, while BESS is employed strategically to address renewable intermittency. For the grid-tied microgrid, optimal power dispatch prioritizes cheaper sources, with Bus 1 contributing the largest share due to its favorable cost profile. Voltage variations remain within acceptable boundaries but indicate potential stability challenges under dynamic load changes, suggesting the need for secondary voltage control. These findings demonstrate the effectiveness of the proposed methodologies in achieving sustainable, cost-effective, and stable microgrid operations.