A framework of utilizing distribution power systems as reactive power prosumers for transmission power systems

Abstract With the increasing penetration of distributed energy resources (DERs), transmission power systems (TPSs) may lack reactive power resources. The concept that distribution power systems (DPSs) could provide adjustable reactive power for its upstream TPS was recently proposed. However, accurately evaluating the reactive power potential (RPP) of a DPS is computationally challenging. This paper proposes a framework to leverage DPSs as reactive power prosumers for the TPS. To resolve the computation challenge, we propose a two-stage linear robust optimization method to evaluate the RPP, where linear DistFlow is used for a lighter computational burden. The uncertainty in DERs and the boundary-bus voltage can also be handled. Then, how the TPS utilizes the DPS’s RPP in the reactive power optimization problem and how a DPS tracks the TPS’s reactive power command are discussed. Case studies show that a DPS is workable as a reactive power prosumer even with notable uncertainty in the DERs, and the proposed linear evaluation method manages to evaluate the RPP fast with reasonable accuracy.