Assumptions on the problem¶

Breakdown of weekly supproblems¶

All uncertainties known within the week are considered, with no visibility on other weeks (except for long-term storage through the heuristic’s deliberately limited visibility, and probabilistically for VU).
Over-optimization of dispatch → lower marginal prices.
Dynamic constraints between weeks are taken into account through cyclicity, which assumes that the residual consumption is the same at the beginning and at the end of the week.

Simple market bid formats.
Actor strategies inconsistent with the minimization of total system costs (EVs not exposed to market prices, monopoly situations leading actors to influence prices to maximize their profits).
Actors arbitrate between preserving flexibility to minimize imbalance settlement, or conversely not necessarily remaining balanced.
More successive optimizations are required to converge toward the minimum cost so that all actors have the same information.

The studied network is a high-voltage grid: the reactance \(X\) is much greater than the resistance \(R\) in a high-voltage network, therefore \(X \gg R\).
The network is highly meshed with relatively short line lengths: the voltage angle difference between two nodes is small.
The voltage level \(V\) is similar along the same line between two nodes: the network is meshed with sufficiently well-distributed generation and consumption.

The zone is assimilated to a copper plate with optimal dispatch.
In NTC, the influence on lines is independent of the location of injections/withdrawals within the zone. In FB and in equivalent network models, part of this information is recovered.

Maximum/minimum flows obtained from different studied supply demand equilibrium situations on the detailed network (in \(N\) or \(N-1\)) → this method overestimates/underestimates capacity.
Linear regression between the equivalent branch flow (sum of line flows) and the maximum congestion rates of lines (in \(N-1\) or \(N\)) → this method is a compromise.

Clusters include units with the same characteristics.
Storages have the same values of P_inj / stock_max and P_inj / P_withdraw, otherwise flexibility would change.

Prices are determined with fixed UC (Unit Commitment); the impact of a start-up is not taken into account → lower marginal prices.
Negative or very low prices require the integration of curtailable power, restrictions on pumping/turbining, and the inclusion of start-up/shutdown information for units (MILP).
Solution close to the optimum but not exact.