Research On Medium And Long Term Multi-objective Unit Commitment Problem In Power Systems

In modern power systems, power source becomes more diverse and their characteristicsof different types of units are different. So their operating requirements are different. We needto contribute a better scheduling for units scheme and output, so that to reducing energyconsume and improving more energy saving potential of the units. For the power systems’effectiveness, reasonable units’ operation arrangement and macro reaction of economicbenefit and safety benefit in a longer period, this paper investigates multi-objective modelingand solution of medium and long term multi-objective unit commitment problem consideringboth economic and environment benefits in power systems.The unit commitment problem is a large, dynamic and non-convex mixed-integerprogramming problem. It’s difficult to solve. This paper builds a model of medium and longterm multi-objective unit commitment that balancing economic benefit and environmentalbenefit. As to obtain uniformly distributed Pareto optimal solutions of the multi-objectivemodel, this paper applies normalized normal constraint to transform this problem to a seriesof single-objective problems, and then solves them by means of GAMS/CPLEX solver.Meanwhile, with the unit commitment model approaching into real environmentgradually, the constraints increase obviously and hence its solution becomes more difficult.Thus, we propose the unit commitment practical algorithm, combining practical constraintrealizing power system unit commitment optimization of units sequencing, units start-updetermination, spare capacity optimization based on equivalent reserve principle, unitsgenerating optimization. To get optimized solution in energy-saving dispatching.Based on real data of a provincial grid, unit commitment problem during a week (168periods) and a month (720periods) are solved by NNC+GAMS/CPLEX and practicaloptimization algorithm respectively. And contrastive and analyses are made. In addition, thispractical optimization algorithm is used to solve unit commitment problem during41daysbefore and after the Spring Festival.