A Review on TSO-DSO Coordination Models and Solution Techniques

The volume of services procured by transmission system operators (TSOs) through distribution-connected resources, aka distributed energy resources (DER), has been increasing in recent years. Currently, distribution networks are assumed to be fully capable of dealing with the resulting power flows. However, this assumption will no longer be valid as the volume of DER services become significant. Therefore, distribution system operators (DSOs) need to have a more active role to ensure the integrity of the distribution network while facilitating DER services. To achieve this, adequate coordination between TSOs and DSOs is required. To help stakeholders understand the implications of different coordination models so they can be adopted or tailored to their needs, this paper identifies three core TSO-DSO coordination models from the many proposed in the literature, discussing the corresponding advantages, disadvantages and challenges. Furthermore, a mapping of the proposed solution techniques is carried out to identify research trends and gaps.