A congestion management formulation with inter-temporal constraints

This paper introduces the generation ramping constraints into congestion management (CM). The California Independent System Operator (CAISO) protocol is used as the basis of the presentation. In CAISO protocol, the forward transmission markets for which congestion management is applied include the day-ahead (DA) and hour-ahead (HA) markets. The protocol requires the modeling of market separation constraints to maintain portfolio balancing separately for different scheduling coordinators in the congestion management process. This paper presents the congestion management formulation with ramping constraints for DA and HA markets. In DA formulation, all hours of the DA scheduling. horizon are coupled together. An interior point method is applied to facilitate the decoupling of the time-constrained CM problem. For HA formulation in which the scheduling is for a single hour, terms modeling the penalty effect of ramping constraints on the future hours due to the adjustments of the current hour are included into the objective function. Congestion charge to scheduling coordinators is calculated using the same formula irrespective to the modeling of generation ramping constraints. Examples are presented for illustration