To effectively harness the significant flexibility from massive distributed
energy resources (DERs) for transmission-distribution interaction, power
flexibility aggregation is performed for a distribution system to compute the
feasible region of the exchanged power at the substation. Based on the adaptive
robust optimization (ARO) framework, this paper proposes a novel methodology
for aggregating system-level power flexibility, considering heterogeneous DER
facilities, network operational constraints, and unbalanced power flow model.
In particular, two power flexibility aggregation models with two-stage
optimization are developed for application: one focuses on aggregating active
power and computes its optimal feasible intervals over multiple periods, while
the other solves the optimal elliptical feasible regions for the aggregate
active-reactive power. By leveraging ARO technique, the disaggregation
feasibility of the obtained feasible regions is guaranteed with optimality. The
numerical simulations conducted on a real-world distribution feeder with 126
multi-phase nodes demonstrate the effectiveness of the proposed method.Comment: 8 Page