Short-term scheduling solved with a particle swarm optimiser

Unit commitment problem is an important optimising task in daily operational planning of power systems which can be mathematically formulated as a large scale non-linear mixed-integer minimisation problem for which there is no exact solution technique. The solution to the problem can be obtained only by complete enumeration, often at a prohibitively computation time requirement for realistic power systems. This research discusses the planning of short-term scheduling on thermal power systems through the particle swarm optimisation technique. The formulation of the problem considers the operating costs of the units, the minimum up and down times, the spinning reserve and the power balance. A methodology is presented, and a computational tool is developed to solve the problem of unit commitment, which handles the problem constraints with correction operators. In the research also is proposed a new way to update the swarm individuals and a mutation stage of the best solution. The method is applied to standard systems and the results are compared with the ones previously reported in the literature. The results obtained by applying the proposed algorithm to the Chile Large Northern Interconnected System are also discussed.