Study On Heating Strategy Of Combined Heat And Power Plants Considering Wind-heat Conflict

At present,large scale wind curtailment is caused by “wind-heat conflict”.The main reason of the conflict lies in the situation that in order to meet the heating load during heating period in winter,the heat-load based combined heat and power(CHP)units must improve the minimum output of electricity production,which leads to the poverty of space for wind power.In view of wind power and thermal power both are important ways of energy conservation and emission reduction in China,it should give priority to the accommodation of wind power or to the development of thermal power,while China's combined heat and power units are actively engaged in the reconstruction of flexibility,how to coordinate the development of the two? The above problems have to be clarified to solve the wind-heat conflict and the coordination between wind power and thermal power.As the reality that the power system and heat system form an integrated power and heat energy system while the combined heat and power plant plays as the coupling point,this paper studies the above problems with the aim of the minimum energy consumption of the whole integrated energy system.The main work is summarized as follows:(1)Analysis of the co-production coal consumption and co-generation heating capacity of combined heat and power plant is the basis to establish an analytical model also to explain the phenomena.Therefore,the power generation cost and heating cost of CHP unit can be separately calculated by decomposing the two;the factors influencing the heating capacity of the combined heat and power plant are analyzed to clarify the influence mechanism.From the perspective of power and energy,the influence of large-scale wind power integration on the heating capacity of combined heat and power plant is analyzed to understand the characteristics of the conflict.The essence and effectiveness of heat accumulator and electric boiler to improve the heating capacity of the combined heat and power plant are analyzed.(2)With the change from "wind-heat conflict" problem into the determination of heating load of combined heat and power plant,the combined heat and power plant operation strategy analysis model is established with the aim of the minimum energy consumption.Through the analysis of the physical meaning of the objective function,coal saving effect is clearly showed of the replacement of combined heat and power plant power generation by wind power,the alternative from coal-fired boiler to combined heat and power units and electric boiler.Based on the analysis of the heating strategy before the reconstruction of the combined heat and power plant,the boundary conditions to decide the priority between the wind power and thermal power.Through the analysis after the reform,the optimal coordination mode of the power wind consumption and the development of thermal power is clarified.(3)While treating the lowest costs of operation and investment of flexibility reconstruction as the goal,the optimal capacity configuration and the optimal heating load model of the thermal power plant are established.At the same time,the principle and the boundary condition of the optimal heating load after the reconstruction of the combined heat and power plant are analyzed.(4)With the simplified integrated energy system built on the actual data,the optimal operation capacity of the combined heat and power plant and the optimal heating load of the thermal power plant are analyzed.The numerical results verify the correctness of the theoretical analysis.The theoretical and numerical examples of this paper showed that,priority should be given to thermal power while the number of abandoned wind power is less than 50% of the total number of cycles before the reconstruction.Priority should be given to the wind power after the reconstruction,and then generating co-production heat as far as possible according to the equivalent load,then the lack of heating load can be added by the heat accumulator and electric boiler.Electric boilers should be actively configured to take full advantage of the idle capacity of the power plant boiler after the accommodation of wind power also to replace the coal-fired boiler with high energy efficient along low emissions CHP units.The work of this paper and related conclusions can provide decision-making reference for the regulators to solve the "wind-heat conflict" problem.