Combined economic and stability analysis of a microgrid: A co-optimisation approach

Both economics and stability analysis are critical to operate electricity networks in an efficient and secure manner, especially in the context of microgrids, where more complex stability phenomena may arise. In this vein, we propose a combined economic and stability model implemented through a hierarchical approach, where a master problem determines the economic system dispatch regardless of stability considerations and then a slave subproblem attempts to stabilize the master's solution through the optimization of control gains. If the economic dispatch solution determined by the master problem cannot be stabilized by slave's adjustments of control gains, a feasibility cut is generated and added to the master problem to calculate a new, more stable dispatch solution (master and slave are run iteratively). We demonstrate that control gains can be co-optimized with power outputs of generating units (in real time) to obtain more economically efficient and secure dispatch solutions and therefore that economics and stability analysis can be combined in a single framework by using advanced optimization techniques.