TSO-DSO Coordination in Decentralized Ancillary Services Markets

TSO-DSO Operational Planning Coordination through "l1-Proximal" Surrogate Lagrangian Relaxation

“…1) The drastic reduction of complexity introduced by a) Binary unit commitment decision variables; b) Nonlinear AC power flow constraints; c) Multiple periods; through the decomposition into TSO "zonal" subproblems and DSO subproblems; 2) The much reduced information exchange and privacy revelation requirements: the TSO only needs to know "interface power exchange amounts," as well as the associated Lagrangian multipliers, which makes the method generalizable to address potential privacy issues; 3) The theoretically proved convergence of multipliers (nodal LMPs) to the optimum under realistic assumptions of the satisfaction of the simple "surrogate optimality condition;" 4) The practical implementability through the use of commercially available MIP solvers (e.g., CPLEX); at the TSO level, only an MILP solver is needed; 5) The satisfaction of original nonlinear AC power flow constraints through the use and penalization of "l 1 − proximal" terms; As discussed above, points 1.a) and 1.c) have been addressed in [1], [2], [4], [30]- [39], points 1.b) and 1.c) have been addressed in [26]- [36] and point 1.b) has been addressed in [2]. Benders decomposition used within [2] cannot be extended in a scalable way to handle 1.a) together with 1.c) because the master problem would contain all the binary variables thereby leading to high computational complexity.…”

“…Consider a distribution network with a radial topology 4 operated by a distribution system operator (DSO) and connected to a TSO's root bus j. Within each DSO, let B D be a set of buses indexed by b D , I D b D be a set of generators at bus b D indexed by i, L D be a set of transmission lines indexed by l. Objective.…”

“…There have been a few attempts at coordinating TSO and several DSOs while considering binary unit commitment variables [1] and [37]- [39]. However, within [1], [2], [4], [30]- [39], DC power flows were considered at the transmission level. A review of the TSO-DSO coordination models and methods can be found at [31], [40].…”

“…Here superscript "T" indicates voltage at the TSO level, while "T" outside of the parentheses indicates the "transpose. "4 Radial topology is considered for simplicity. Power flows within DSOs with meshed topologies can be modeled in the same way as within the TSO as described above.…”

TSO-DSO coordination to acquire services from distribution grids: Simulations, cost-benefit analysis and regulatory conclusions from the SmartNet project

“…In order to manage the services requested for all the system voltage levels, Transmission and Distribution System Operators (TSOs and DSOs respectively) need to coordinate their actions by means of optimized and formal architectures which foresee exchange of data, provision and prioritization of services, shared market schemes, etc. A number of possible TSO-DSO Coordination Schemes (CSs) have been investigated [4]- [6] with general conclusions on their implementations drawn in [2] and practical experience of power sector stakeholders [5], [7]. In particular, it is demonstrated that TSO-DSO coordination is always beneficial [1], [2], [5], [6], [8], with the potential negative impacts of uncoordinated actions in terms of system operation and commercial market player business discussed in [3].…”