Study On Optimal Energy Flow Strategy Of Electric Thermal Integrated Energy System Based On Interior Point Method

With the depletion of fossil energy and the increasingly serious environmental problems,China’s energy development direction should be developed in the direction of higher comprehensive utilization rate and lower pollution emissions.The electricity-heat integrated energy system is an important manifestation of today’s energy system.It includes two energy forms of electricity and heat.The complementary transformation between the two energy forms realizes the efficient use of energy between different systems.These characteristics make the electricity-heat integrated energy system have the advantages of flexible operation,coordinated energy supply,low carbon environmental protection and high efficiency and reliability.The research on the energy flow calculation method and the optimal energy flow strategy of the integrated energy system is an important research direction of the integrated energy system.By using the two control methods of electricity and heat,the electric heating system is optimized jointly,and the system is operated in the operation state of both economy and flexibility.This thesis will study the electric-thermal integrated energy system,and the main research contents and work are as follows:Firstly,the mathematical model of power supply equipment,heating equipment and electro-thermal coupling part is analyzed.By studying the working principle and operation characteristics of each working element in the electro-thermal integrated energy system,the operation mechanism of the electro-thermal integrated energy system and the flow and transformation of electric energy and heat energy in the electro-thermal integrated energy system are analyzed,which lays a foundation for the study of optimal energy flow strategy.Secondly,the energy flow calculation model of power system and thermal system is analyzed,and the energy flow solution model based on the energy flow equation of electric-thermal integrated energy system is proposed.Relying on the forward and backward substitution method,an improved power flow algorithm for power system considering distributed power access and an improved energy flow algorithm for thermal system based on heat source decomposition are proposed respectively.According to the relationship between the subsystems in the integrated energy system,a unified energy flow solution method for the integrated energy system is proposed.The simulation calculation is carried out by MATLAB simulation software.It is verified that the proposed algorithm can greatly improve the energy flow calculation process of the electric-heat integrated energy system and ensure that the calculation results have high accuracy.Compared with the traditional Newton-Raphson method,it has good PV node processing ability.Under the premise of realizing the unified calculation method of electric-heat integrated energy flow,it has the advantages of good convergence and simple programming,which reduces the difficulty of solving the energy flow of the electric-heat integrated energy system.Finally,based on the analysis of the energy flow model and calculation method of the electric-thermal integrated energy system,combined with the structure and operation characteristics of the power system and the thermal system,the optimal energy flow model of the electro-thermal integrated energy system is constructed,which includes the operation constraints of the power system,the thermal system and the electro-thermal coupling device,and the lowest operation cost and stability of the system.By introducing an adaptive compression factor to improve the traditional interior point method,an improved interior point method is proposed and its process and method for solving the optimal energy flow model are analyzed.According to the operation target of the system,the optimal energy flow can make the electric-thermal integrated energy system closer to the operation target of the system by optimizing the operation parameters of the electric-thermal integrated energy system within the constraints of the control variables,and the optimal energy flow can make the system more economical and stable.