Profit based unit commitment considering the cold reserve under competitive environment

In this paper, an analysis of the effect and importance of cold reserve in daily generation planning of a power system is done. A mathematical formulation for unit commitment based on the profit is presented and it considers the maintenance cost and the fixed revenue for the unit that will be held as cold reserve. In this work, the solution method is based on the Lagrangian relaxation (which introduces the demand and reserve constraints into the objective function by means of multipliers) and evolution strategies (up dating of the Lagrange multipliers is usual), so it solves a dual problem. A three-unit test system was used to show how the cold reserve market could influence the scheduling of a generation company. Two scenarios were modeled for the simulations. The first one considers a normal profit-based planning. The second one, a real life scenario in which cases, such as loss of generation units, loss of transmission lines are also included. Tests using an illustrative small system are presented, showing the usefulness of the integrated generation scheduling considering both, the spinning reserve and cold reserve.