unit commitment; thermal generating units; optimization
The purpose of economic thermal unit commitment scheduling is to minimize the cost of operation subject to attainment of a certain level of security and eliability.However, in recent years, owing to environmental con-siderations, operation at absolute minimum cost cannot be the only objective/basis of optimal thermal unit commitment.The environmental effect of thermal power generation is also becoming a major concern in most countries. This paper flrst introduces the general unit commitment scheduling problem and then discusses various considerations, objective functions and different techniques to solve the problem. A brief critical representative survey of the existing literature available on this topic is presented. Finally, recent trends in research on unit commitment are also discussed.