Research On Electro-thermal Coupling Scheduling Method Considering Combined Heat And Power Units’ Reserve

During the heating period in the "three norths" area,the ability of combined heat and power(CHP)units to support the flexibility of the power system is an important factor affecting wind power consumption.Limited by the rigid demand for heating by residents in winter,the electricity and heat output of the CHP units under the " power determined by heat" operation mode is in a coupled state,which makes the electricity output flexibility of the CHP units poor.Analyzed from the perspective of electric and thermal coupling energy system scheduling,through the coordination between the heat output of the CHP units and the related heat storage components of the thermal system,the flexibility of the CHP units can be effectively improved without increasing investment.However,the flexibility of CHP units requires different forms of power system operation and power system control.The operation phase requires the units to have a certain degree of flexibility,while the control phase requires the units to have a certain degree of flexibility for reserve.The current research on the scheduling model of the electricheat coupled energy system ignores the flexibility reserve of the CHP units,which causes the CHP units to be unable to participate in the system reserve flexibility support in the actual control process.To this end,this article focuses on the issue of the dispatch of an electro-thermal coupled energy system considering the reserve of the CHP units.The specific work is as follows:(1)Aiming at the problem of insufficient reserve flexibility in the power system,this paper proposes a scheduling model that takes into account the reserve of the CHP units.First,based on the operating characteristics of the CHP units under the control mode of extraction steam,the flexible reserve extended interval of the CHP units under the coordination of heat storage is established.Then,combined with the related principles of thermodynamics,the coupling relationship between the reserve of CHP units and the reserve of heat reserve of the building is analyzed quantitatively,and the coupling support equation between the reserve of the CHP units and the heat reserve of the building is obtained.Finally,based on the coupling support equation,a dispatch model of the electro-thermal coupling system considering the reserve of the CHP units is established,which lays the foundation for the subsequent systematic research on the dispatch of the electro-thermal coupling system.(2)Aiming at the problem that the spare flexibility mining of the CHP units requires the coordination support of the relevant heat storage links of the thermal system,this paper proposes an electric-heat coupling system scheduling method that takes into account the coordination of multi-source heat storage.First,the quasi-dynamic process of heat energy transmission through water and heat loss in the pipeline are analyzed.Then,on the basis of the quantitative coordination equations for reserve of CHP units and heat reserve of the building,the constraints of multi-stage heating network pipelines are taken into account,and the multistage heat storage system considering primary heating network heat storage,secondary heating network heat storage,and building heat storage are established.The coordinated scheduling method of electric and thermal coupling with multi-level heat storage cooperative support,and the centralized scheduling strategy is adopted to solve the model.The simulation example compares and analyzes the models with three scenarios,and verifies that the proposed model improves the flexibility reserve of the power system,reduces the wind abandonment,and reduces the total dispatch cost of the electro-thermal coupling system.(3)Aiming at the problem that the power system and the thermal system belong to different dispatching subjects in the electric and thermal coupling system dispatching,this paper proposes a solution strategy for the decomposition and coordination of the electric and thermal coupling system that takes into account the reserve of the CHP units.First,the characteristics of the power system and the thermal system in the electrothermal coupled energy system are analyzed.Considering the multi-agent scheduling problem under the independent operation of each system,a decomposition coordination solution strategy based on coordination is proposed.The framework and calculation process of the solution strategy are introduced,and it is applied to the solution of the scheduling model of the electrothermal coupling system that takes into account the reserve of the CHP units.The simulation example verifies the effectiveness of the proposed solution strategy in solving complex electro-thermal coupling system scheduling problems with high computational dimensions.