Aggregate Operation Model for Numerous Small-Capacity Distributed Energy Resources Considering Uncertainty

Numerous small-capacity distributed energy resources (DERs) pose technical challenges and increase the management complexity for power system operators. This article proposes an aggregate operation model to efficiently manage a large number of DERs with heterogeneous parameters. The aggregate operation model includes the approximate feasible region and the equivalent operational cost function. First, considering the coupling of power, energy, and regulation service, the operational flexibility of multiple categories of DERs is modeled by a general polytope. Second, by scaling and translating a basic homothetic polytope, a maximum inner aggregation approach is formulated to exploit the potential flexibility of DERs and guarantee solution feasibility. The uncertainty of DERs is modeled by the distributionally robust chance-constrained program (DRCCP), and the equivalent cost function of the DER aggregator is rigidly derived. Last, this study theoretically explains that the aggregate feasible region can be enlarged by introducing the DER clustering process, and a spectral clustering algorithm based on the multi-scale similarity metric method is developed to classify DERs into different aggregators. Numerical simulation results indicate the great potential of the proposed method to enhance system operational flexibility with high computational efficiency.