Research On Optimal Load Dispatch Of Units In Power Plant For A Comprehensive Economical Goal

With the development of China's socialist market economy, the structural reform of electricity industry is going on. The object of the reform is to establish an electric power market. In the market environment, how to make the units'load dispatch optimal is important for a power plant to reduce energy consumption, maximize profits and increase competitiveness.The topic of this paper is unit load optimal dispatch in power plant, two issues are discussed: load dispatch and unit commitment.The topic of this paper is unit load optimal dispatch in power plant. there are five units in the power plant which is the specific object this paper studies on. Two of these units use industrial waste gas as thermal, and the other three are coal-fired units. Besides, there units are not the same type, one is gas turbine unit, and the other four are boiler units. Regarding to this multi-type, multi-fuel power plant, this paper mainly studies two issues: load dispatch and unit commitment.Theoretical analysis indicates that the plan of load allocate according to the equal incremental principle is optimal when the units participate in load allocate is determined. This paper analyses the application of the equal incremental principle in the subject of load allocate, and use the equal incremental principle to calculate the load allocate for a power plant which owns different type units. The results show that the equal incremental principle is applied to the issue of unit load allocate when the functions of the units'coal consumption curves are convex functions.This paper gives the mathematical model of unit commitment, analysis the basic principle of dynamic programming, gives the algorithm as using dynamic programming method to solve this problem, and designs the calculation program. The practical factors such as the start consumption, the minimum running time and the minimum halt time, the life loss in the process of unit start are considered in this paper, and various factors that influence the result are compared.This paper introduces the life loss in the process of unit start into the calculation of the optimal dispatch. In the process of calculating, the start consumption and life lose of unit are set constants, such a treatment not only ensures the reasonability of calculation, but also avoids the unreliable caused by the excessive complex of calculation. Actual results indicate that the life loss of unit have a negligible impact on unit load dispatch.Considering the situation that the power plant must fire the waste gas in order to protect the environment, this paper designs the treatment of compulsory load instruction to make the calculation result meet the requirement of the actual situation. Meanwhile, this treatment shall reject some unreasonable unit commitments, and reduce the calculation complexity.This paper dose some actual load optimal dispatch calculation for a power plant which owns different type units, and the results show that dynamic programming method combined with the principle of equal incremental is applied to solve the problem of optimal load dispatch, it shall reduce the coal consumption and bring economical benefits for power plants.