Integration of Operating Reserve Constrains in the Predictive Optimal Dispatch of Energy and Storage Resources in Small Islands

The progressive integration of Distributed Energy Resources (DERs) at distribution and end-users level is redefining the approach of Distribution System Operators to power system operation. The power fluctuations caused by intermittent Renewable Energy Sources (RES) require the provision of large amounts of operating reserve and flexible resources. The effect of intermittent RES on power systems has a greater impact in small isolated distribution systems such as the ones that supply small islands not electrically connected to the mainland. Due to the impossibility of exchanging power with the interconnected main grid, in these peculiar distribution systems, it is necessary to ensure power balance at all times. In this paper, a predictive control methodology is proposed with aim of ensuring both optimal dispatch of resources and reliability. Since the approach is proposed for applications on small islands, the optimal control formulation integrates operating reserve constraints. The paper discusses the role of storage resources in ensuring reserve, proposing different formulations of reserve constraints. Test results are carried out using the representation of the distribution system of an actual Italian small island.