Robust Dynamic Operating Envelopes for DER Integration in Unbalanced Distribution Networks

Dynamic operating envelopes (DOEs) have been introduced in recent years as a means to manage the operation of distributed energy resources (DERs) within the network operational constraints. DOEs can be used by network operators to communicate DER dispatchable capacity to aggregators or customers without further consideration of network constraints and are thus viewed as a key enabler for demand-side participation in future electricity markets and for ensuring the integrity of distribution networks. While a number of approaches have been developed to calculate DOEs, uncertainties in system data are typically ignored, which can lead to unreliable results and introduce security risks in network operations. This article presents a deterministic procedure to calculate robust DOEs (RDOEs) explicitly hedged against uncertainty and variability in customers' loads and generations. The approach is based on a geometric construction strictly included within the feasible region of a linear unbalanced three-phase optimal power flow problem that specifies the network operational constraints. The article analyses and rigorously shows that the proposed approach also delivers proportional fairness in capacity allocations, and demonstrates how the RDOEs can be enlarged by i) exploiting the knowledge of customer operational statuses and ii) by optimising customers' controllable reactive powers. The efficiency and compliance of the proposed approach are characterised and discussed for three numerical case studies of varying complexity: a 2-bus conceptual distribution network, a 33-bus real-world Australian representative low-voltage distribution network, and a 132-bus low-voltage distribution network synthetically constructed by extending the 33-bus network model.