Interactions between Active Distribution and Transmission Networks: State of the Art and Opportunities

The transmission system operators (TSOs) are used to procure network services from large power plants. However, the network service procurement by TSOs is recently being changed due to the gradual shutdown of fossil-fired plants for net zero transitioning and the emergence of distributed energy resources (DERs) in active distribution networks. These DERs, with the aid of appropriate aggregators, can provide energy arbitrage and ancillary service opportunities for the transmission network. Consequently, enhanced coordination between transmission networks (TNs) and active distribution networks (ADNs) becomes a crucial issue. In this work, we assess the viability of addressing various aspects of integrating RESs through improved TN/ADN coordination. Specifically, we perform a critical literature review to lay the groundwork for upcoming studies aimed at creating a TN/ADN coordination system to facilitate the integration of RESs. The review’s findings exhibit an evident focus in favour of the decentralised method due to its effectiveness in aggregating services from renewable energy sources, reducing computational complexity and communication overhead, and consequently lowering operational costs.