This suite of tools is adapted to the representation under uncertainty of integrated energy systems – involving multiple generation technologies and taking into account the availability of renewable resources, fuels and transport restrictions in transmission lines and pipelines. The various models use stochastic optimization techniques to solve operational and planning problems.

NCP – Short term operation programming

NCP determines the operation of a transmission-constrained hydrothermal system in order to minimize costs or to maximize revenues of energy sales to the market. Costs include fuel usage (variable production and startup costs), deficit costs, and penalties for the violation of operational constraints, among others.

Modeling Aspects:

The following features are modeled by NCP:

  • Load balance for each bus of the transmission network, including quadratic losses in the transmission grid
  • Linear power flow model, including circuit flow capacity constraints for the base case and contingencies
  • Water balance equation for hydro plants in river cascades considering the water travel time and wave propagation
  • Minimum and maximum power levels for each power plant, including unit commitment decisions
  • Reservoir minimum, alertness and flood control storage volumes
  • Minimum and maximum downstream water outflows and constraints for the rate of change of these outflows
  • Coupling alternatives with mid-long term studies include: generation target, end-of-period storage target or reading a future cost function
  • Thermal plant constraints: minimum up-time and down-time, power ramping rates, fuel availability and number of startups
  • Hydropower function at unit level considering the turbine-generator efficiency curve, the hydraulic losses, the tailwater elevation and the head x storage relationship
  • System security constraints (primary and secondary reserves, sum of circuit flow constraints, general generation constraints, etc)

The solution is achieved using advanced Mixed Integer Programming (MIP) techniques.

System Characteristics

  • Windows-based user graphical interface
  • Includes module to graph output results and display them in Excel
  • Various output results (ex: hydro and thermal power, marginal costs, circuit flows, reservoir storage levels, etc)

Integration with SDDP

SDDP’s power system components and calculated future cost function may be imported by NCP. This integration is automatic within the ePSR, which also exports NCP results to EMS applications and offers additional functions, such as an automatic preparation of the initial conditions for re-dispatch studies.

Integration with OptFlow

NCP results can be imported by Optflow - an optimum power flow model that determines the injection of reactive power to guarantee the required voltage level.

Example of applications

  • National load dispatch centers of Bolivia, Ecuador, Guatemala, El Salvador and Peru (the daily and weekly scheduling)
  • Largest generating companies of Turkey, with more than 30,000 MW
  • Various institutions in the Balkans region in activities related to the Southeast European Electrical System Technical Support (SEETEC) project
  • Agder Energi (Norway) for maximizing revenues in the Nordpool market
  • Evaluation for determining the scheduling of the Brazilian power system (~5800 circuits, 3900 buses and more than 100 hydro power plants)