Aggregation and packaging of distributed energy resources: A time-coupled flexibility-demand-oriented method

In power systems with high renewable penetration, aggregating and packaging demand-side distributed energy resources (DERs) is crucial for effectively harnessing their flexibility potential. Traditional approaches employ generic models to characterize the aggregated flexibility of diverse DERs, while their inadequate consideration of multi-time coupled flexibility demand leads to either overly conservative estimates or partially infeasible control solutions. To address these challenges, this paper proposes a novel time-coupled flexibility-demand-oriented aggregation and packaging method that offers high accuracy, fast convergence, and strong adaptability in DER flexibility characterization. First, for homogeneous resources, we introduce an improved inner approximation method based on homothets, effectively resolving the dimensional inconsistency issues and handling the nonlinear charging-discharging complementarity constraints. Then, for heterogeneous resources, we develop a vector aggregation optimization model along target curves, which characterizes the temporal coupling characteristics of aggregated output power. Moreover, we propose a dynamic aggregation packaging method that adaptively updates the aggregation feasible domain dictionary to enhance practical applicability. Case studies demonstrate that our approach reduces aggregation errors by up to 50 % compared to traditional methods while maintaining computational efficiency (average solving time < 5s).