| In order to solve the problems of the low energy utilization efficiency and improve the increasingly tight supply and demand relation,the scope of application of integrated energy system has been continuously expanded and it can separate the individual planning and operation limitations of the present energy supply systems.The degree of coupling continues to deepen among various types of energy supply systems such as electricity,heat,cold,and gas.Most of the current traditional analysis about combined thermal and electric energy system focuses on the electric power system.Modeling of heating systems,especially for heating pipe networks,is often ignored or approximated.And it usually considers the balance of energy and the constraints of the pipe network are not considered.At the same time,the recovery and reconstruction under the failure condition of the integrated energy system are often under the single energy supply system,especially the electric power system,and it lacks coordination and cooperation among the various energy supply systems.Therefore,it is necessary to calculate the optimal energy flow for the combined thermal and electric energy system.The reconfiguration strategy of electricity and heat network structure is researched about the recovery of integrated energy systems.This thesis researches the electrothermal coupling integrated energy system.It researches the optimal energy flow calculation method for the combined thermal and electric energy system considering thermal network constraints.The recovery and reconfiguration strategies for integrated energy system is proposed considering the electricity and thermal networks.This thesis can be divided into three parts.(1)The refined modeling method of heating pipe network was studied.It not only considers the system energy balance,but also pays attention to the network balance of the heating system.In the calculation of thermal energy,the model considers the constraints of the pipeline and the heat energy transmission losses,which provides a more accurate model for the subsequent calculation of the optimal energy flow.The heating system load model is established based on the heat load temperature demand.And the mathematical model of the heating user’s temperature requirement and the heat load of the heat exchange station of the primary heat network is established by using the heat exchangers,heat exchangers and other key equipment of the heating system.Modeling the hydraulic and thermal conditions of the heating system separately.A reasonable solution method was proposed and verified by examples.(2)Based on the power flow analysis of the power system,the thermal conditions of the heating system are analyzed.By linearizing the thermal conditions of the heating system and rewriting the heat source and heat load,the optimal energy flow solutionmodel of the electrothermal coupled integrated energy system is established based on the optimal power flow equation of the power system.The principle of the interior point method and the actual calculation flow were analyzed.The optimal energy flow model was analyzed.The solving method was given and verified by relevant examples.(3)Based on the integrated energy system model,the complementary replacement capabilities of different energy systems in an electrothermal coupling integrated energy system are analyzed.Firstly,the fluctuations of the power outputs and heat source outputs of the CHP units are compared and analyzed,as well as the network loss and fluctuations of electricity and heat load,whether the thermal network constraints are considered.The output of the unit was analyzed when the power grid and the heat pipe were withdrawn,and the role of the electric boiler and other coupling elements in the complementary energy substitution was analyzed.On this basis,the genetic algorithm is used to solve the network reconfiguration recovery strategy that minimizes the loss load when the line exits. |
PDF Full Text Request