A review of practical aspects of existing TSO-DSO coordination mechanisms in Europe and proposal of an innovative hybrid model in ATTEST project

The transition towards a carbon-neutral power system puts the focus on unlocking local flexibility potential. Providing ancillary services (AS) on the local level arises as a new option in power system operation and control due to the increasing growth of distributed energy sources (DERs). To facilitate the possibility of distribution level users to provide system-wise services, system operators need to coordinate their actions and operational plans. To avoid the activation of counteracting service, the coordination between the Transmission System Operator (TSO) and the Distribution System Operator (DSO) is required in multiple time horizons, from a day or weak ahead to real-time. The paper reviews several approaches in TSO-DSO coordination in different market environments pointing out the main features, advantages, and drawbacks of each coordination scheme. Unlike previously investigated coordination schemes, the paper proposes a novel coordination mechanism which is being developed in ATTEST project. The coordination is divided into day-ahead (DA) and real-time (RT) stages and describes the sequence of each system operator’s action in the AS reservation and activation procedure.