Network-secure aggregator operating regions with flexible dispatch envelopes in unbalanced systems

Expansion of DER capacity in distribution networks increasingly requires DSO coordination to prevent violation of network limits. Dynamic operating envelopes (DOE) facilitate network-secure integration of DER in wholesale markets by applying variable connection-point import/export limits. In unbalanced networks, conventional DOE approaches may lead to network-infeasible outcomes when envelope utilisation is uncertain. The robust dynamic operating envelope (RDOE) approach in literature addresses this limitation, however DER participation in wholesale markets is significantly reduced compared to conventional DOE. We propose robust aggregator operating regions with flexible dispatch envelopes (RAR-DE), combining the strengths of DOE and RDOE approaches. We leverage aggregators' abilities to coordinate customers, enabling the DSO to assign sophisticated operating regions that maximise their market participation. The DSO then facilitates adherence to complex regions, providing parameters to compute market-responsive envelopes for each DER. Simulations demonstrate the combination of favourable market participation opportunities and network-feasible outcomes.