Multi-Actor DSO-TSO Congestion Management and Voltage Control Coordination with a Two-Level ADMM

Massive penetration of distributed energy resources (DERs) along with limitations of the network are increasingly causing congestion or voltage problems in transmission and distribution systems. The interconnectedness of these systems necessitates coordination amongst their operators to assure supply security. This paper proposes a methodology for coordination amongst a Transmission System Operator (TSO) and Distribution System Operators (DSOs) without any hierarchy imposed on the entities. Coordination enables optimal usage of flexibility from Active Distribution Systems (ADSs) by the TSO and mitigation of congestion and voltage problems. This work leverages a two-level Alternating Direction Method of Multipliers (ADMM), which guarantees convergence to an approximate stationary solution for multi-block problems involving multiple actors. Tested on a modified IEEE 118-bus transmission system coupled with IEEE 33-bus active distribution test systems, the benefits of the proposal are demonstrated.