Operational Optimization of a Microgrid with Differential Algebraic Constraints

This paper is concerned with the optimal operation of microgrids, which progressively operate closer to their stability limits due to high penetration of renewable generation and the ever-increasing interconnection with the main grid. To tackle this problem, the paper proposes an appropriate transient stability constrained OPF (TSC-OPF) that integrates system dynamic constraints governed by relevant differential equations. A direct transcription method and specifically a simultaneous collocation method is utilized, as it has been found to exhibit greater performance in comparison with other methods reported in the literature. The developed model is applied in the operational assessment of a generic, islanded microgrid comprising of a conventional and a renewable generator to demonstrate the benefits for its transient performance. It has been shown that the added transient stability constraints enable the determination of a dispatch that avoids the violation of any stability limits.