SCED Details

A Security Constrained Economic Dispatch plan, or SCED, determines the power output level of each dispatchable generator during a single timestep of the simulation. SCEDs work in conjunction with RUCs (Reliability Unit Commitment plans) to simulate operation of the power network.

Each SCED determines operational parameters of each dispatchable generator for a single time step. The SCED coordinates changes to generator setpoints to minimize total costs for the system as a whole. The decisions in a SCED are made by building a model which reflects the state of the power network at the current simulation time, forecasts for future loads and future renewable power generation, and unit commitments as dictated by the most recently activated RUC. The model is solved to find the most cost-efficient way to satisfy current and forecasted loads while honoring system constraints such as reserve requirements and line limits. SCEDs always honor unit commitment decisions made by the active RUC. The number of hours of forecast data to include in the SCED model is determined by the SCED horizon.

If market settlement is enabled, additional market-related statistics are calculated with each SCED. These statistics report performance against day-ahead commitments and reserve requirements and the resulting impact on generator revenue.

SCEDs are generated more frequently than RUCs. Where a new RUC is typically generated between 1 and 4 times a day, SCEDs occur at least hourly. The SCED frequency determines how often a SCED is generated, and also serves as the size of the simulation time step.

Prescient provides several plugin points to allow the SCED generation process to be observed or modified. These are documented in the Detailed Prescient Simulation Lifecycle.