A Novel TSO-DSO Ancillary Service Procurement Coordination Approach for Congestion Management

This paper proposes a novel TSO-DSO coordination approach which aims to optimally procure ancillary service (AS) for congestion management in day-ahead operation planning framework. The proposed three-step approach consists of: (i) provision of active power flexibility range along with the associated cost by the Distribution System Operators (DSOs) at TSO-DSO interface, (ii) procurement of active power by the Transmission System Operator (TSO) for relieving congestion in its system and (iii) optimal re-dispatch of existing flexible resources by DSOs in active distribution systems (ADSs) to maintain the committed active power schedule at their TSO-DSO interface and to ensure the reliable operation of ADSs. Furthermore, both real-world N-1 security criterion at TSO level and inter-temporal aspects of emerging flexible resources such as flexible loads (FLs) and energy storage systems (ESSs) at both TSO and DSO levels are considered. Accordingly, the proposed approach is based on the deterministic multi-period AC security-constrained optimal power flow (MP-SCOPF) at TSO level and multi-period AC optimal power flow (MP-OPF) at DSO level, formulated as non-linear programming (NLP) problems. The applicability of the proposed methodology is demonstrated on a power system connecting a 60-bus transmission system with five 34-bus ADSs.