Research On Day-Ahead Optimal Operation Of Integrated Energy System

In order to solve the global problem of environmental pollution,accelerating the energy transition is a universal response strategy for countries around the world to deal with climate change.The integrated energy system(IES)is proposed to change the existing energy structure and improve utilization efficiency of energy.It is a multienergy complementary combination that is based on the power grid and connects various primary and secondary energy sources through coupling equipment.Since the network,equipment,load,transmission and conversion of different energy systems have different attributes,time scales,and response characteristics,it is important to determine the IES operation strategy as a whole.It needs to consider the different operating characteristics of electricity,gas,and heat in terms of time,space,and behavior factors,so as to achieve coordination among different energy forms.The background and development of the IES are briefly described in this dissertation.Through comparative analysis of existing technology and future development trends,proton exchange membrane(PEM)electric hydrogen production equipment,solid oxide fuel cell(SOFC)combined heat and power equipment and gas source heat pumps are selected as coupling components between energy networks.For the selected coupling equipment,this dissertation analyzes its composition structure and the operating mechanism of each part,establish es its detailed mathematical model,and then simplifies the model within a reasonable range through actual equipment parameters to meet the linearization requirements of subsequent optimization problems.Network modeling for each subsystem of the integrated energy system are performed in this dissertation,among which the power subsystem is described by the Dist Flow model;the thermal subsystem is simplified to a network model operating in the constant flow variable temperature(CFVT)mode considering heat loss;for comparative analysis the impact of the natural gas pipeline’s “storage” characteristics,a steady-state model based on Weymouth and a dynamic model based on NavierStokes equation are established,and they are linearized by finite difference method.A single-objective mixed integer linear optimization(MILP)model that takes energy purchase costs,wind abandonment costs,and overall carbon emissions into account as the objective function is established,and all nonlinear constraints are linearized through piecewise linearization in this dissertation.Through certain case,it is verified that the spatial characteristics embodied by multi-energy coupling and the time characteristics embodied by the "storage" effect on the absorption of renewable energy power generation.Then this dissertation explains the method of establishing the optimization problem based on the data fitting model,and verifies its feasibility,and compares the running time of different models.