DSO-TSO Cooperation Issues and Solutions for Distribution Grid Congestion Management

Abstract

The role of DSOs is evolving due to the increasing penetration of intermittent and distributed energy resources in the distribution system. On the one hand, TSOs are accessing flexibility resources connected to the distribution grid. On the other hand, DSOs are actively managing distribution grid congestion, moving away from the conventional fit and forget approach. As a result, the need for DSO-TSO cooperation has become increasingly important. In this study, we first discuss market and grid operation issues related to different system states and the corresponding congestion management approaches. Second, we discuss possible solutions that are inspired by inter-TSO cooperation solutions as well as solutions that are being adopted by DSOs. Our findings show that the issues are rather similar both at transmission and distribution level; however, the need for cooperation and the solutions will depend on where structural congestion will occur and which borders will be managed.

Transmission and distribution coordination in power systems with high shares of distributed energy resources providing balancing and congestion management services

“…It is the case for network and system planning, for data exchange between SOs, coordination in preparation and activation of corrective actions, coordination in pre‐qualification and activation of DER (CEER, ). The Network Codes also set the rules for cooperation among TSOs, which may serve as an example for the future cooperation between TSO and DSO (Hadush & Meeus, ).…”

“…However, another important question is how to ensure that the activation of the procured DER flexibility will not generate congestions in the real‐time. For this purpose, an important coordination tool could be the “traffic‐light system” (Hadush & Meeus, ). The idea is to forecast the congestion state of the system and operate markets accordingly.…”

The electricity market design for decentralized flexibility sources

“…Previously, there was limited interaction between TSOs and DSOs in terms of acquiring electricity flexibility (Gerard et al, 2018). Prior coordination between TSOs and DSOs only concerns network planning, common data platforms or metering data sharing (de Jong et al, 2016;Hadush & Meeus, 2017). The model of coordination between DSOs and TSOs will lead to different market designs and system services.…”

Congestion Management in Distribution Networks With Asymmetric Block Offers

“…These resources are able to provide flexibility to both TSO and DSO, and are also allowed to participate in the day-ahead market through new market players, such as aggregators and balancing responsible parties. Key is that the TSO and DSO need to coordinate how to use the DERs, ensuring both have access to flexible resources while operating their underlying system in a secure manner [2].…”

“…Accounting for the rebound effects, two models are mixed-integer linear programming (MILP) problems (one without and one with loss approximations), while the last one is a mixed-integer second order cone problem (MI-SOCP). The latter model is a convex conic relaxation of the original AC-OPF model, which performs 2 Adding block offers is common place in European zonal electricity markets, as conventional generators are allowed to submit different types of block offers to ensure their internal unit commitment constraints [14].…”