Models Of Coal Blending In Coal-fired Units And Optimization Algorithms Of Multi-unit Combined Scheduling

With the rapid growing of economic and the increasing of the total social electricity consumption year by year,the power industry has become an important industry to support economic development in China.It is well known that China is rich in coal,but poor in oil and little of gas,so coal-fired units are still the main generation means.Facing the increasingly energy situation and environmental pressure,to promote the energy conservation and emission reduction of coal-fired power generation enterprises will be an inevitable requirement to maintain the sustainable development of China’s economy.Based on the research of the energy saving and emission reduction of electric power production enterprises,the safe and economic operation of coal-fired units and multi-unit combined scheduling,this dissertation has conducted sufficient research on optimization problems in the process of power generation,such as coal blending,economic dispatching and unit commitment in power systems.The main contributions are as follows:(1)The cuckoo search algorithm’s variants and applications are summarized and its parameter settings are studied in detail.The sensitivity analysis of such parameters is carried out on six benchmark test functions.Simulation results show that the cuckoo search algorithm is very sensitive to different values.However,a good combination of parameters is obtained by orthogonal experiment.(2)Coal blending technology can be made use of solving the mismatch coal quality problem between the actual supplied coal and the designed requirement,hence to reduce generation cost and improve production effectiveness.Based on the analysis of the relationship between single coal and the blend,this dissertation formulates a resourceconstrained 0-1 mixed integer programming model by using the minimum blending cost and limiting the number of single coal.In order to further reduce the blending cost and keep the blend not slagging in theory,partial of the coal’s quality indicators of the blend are allowed to exceed the standard value,and the exceeding parts are added into the objective function as a penalty,then a new model is established.Simulation results verify the effectiveness of the new model.A lower blending cost is obtained on the premise of a small sacrifice of some coal’s quality indicators.(3)The classic economic dispatch problem is studied,which has non-convex,noncontinuous and non-linear solution spaces and is difficult to solve.In this dissertation,an improved cuckoo search algorithm is proposed to solve this problem.First,the structure of the solution is defined.Then the self-adaptive step size factor and the neighbor-study strategies are established to improve the algorithm’s ability of exploration and exploitation.The improved λ iteration method is used to improve the speed of generating a new solution.Simulation experiments are carried out on the benchmark test systems of 6,13,20 and 40-unit.The simulation results show that the improved cuckoo search algorithm is effective and better than other algorithms in the literature,especially for large-scale unit systems.(4)An improved binary cuckoo search algorithm is proposed to solve the classic unit commitment problems in power systems.First,a two-dimensional array is used to define the structure of the solution.Next,a new binary updating mechanism is introduced to help the proposed algorithm to choose a feasible direction.A heuristic search algorithm based on information exchange strategy and a new priority list is used to improve the ability of exploitation.A greedy repair strategy is used to increase the diversity of solutions.Simulation experiments are carried out on the benchmark test systems from 10 to 100unit.The simulation results show that the improved binary cuckoo search algorithm can solve the unit commitment problems efficiently.Compared with other algorithms,it is faster and the solution quality is higher.Through the study of relevant problems of coal-fired units,new methods are proposed in the decision-making of coal blending,traditional economic dispatching and classic unit commitment.The experimental results also verify the effectiveness of the new methods.It lays a theoretical foundation for energy conservation and emission reduction of thermal power plants and further engineering application.