Stochastic Energy Coordination in Hybrid AC/DC Smart Grids

This paper presents stochastic energy management system (S-EMS) in hybrid ac/dc smart grids. The developed S-EMS coordinates the operations of various distributed resources (DRs), i.e., distributed generators (DGs) and energy storage systems (ESSs). It also ensures coordinated charging of the plug-in electric vehicles (PEVs). The energy management problem is formulated as a two-stage day-ahead resource scheduling problem with both the intermittent supply and the variable PEV demand modeled as random variables. The first-stage determines the unit commitment (UC) decisions for the next 24 hours, while the second-stage determines the corrective decisions, which include the import/export schedule, the storage charging/discharging cycles, and the PEV charging patterns for a set of possible scenarios. The objective is to minimize the expected total operating cost while satisfying the operational and technical constraints. The developed centralized two-stage stochastic EMS model is tested on a 38-bus hybrid ac/dc distribution system. The simulation results demonstrate the effectiveness of the developed EMS model to optimally coordinate the various components of the future hybrid ac/dc smart grid.