Research On Multi-stage Planning Of Integrated Energy System

The integrated energy system breaks the barriers between different sub-energy systems and realizes the organic coordination of different energy sources.It has received extensive attention in recent years.The coordinated optimization planning of multiple energy sources in the integrated energy system can improve the reliability of energy supply and the efficiency of energy utilization,thereby promoting the development and utilization of renewable energy.The planning cycle of the integrated energy system is relatively long,and the single-stage planning method without considering the load changes is currently widely used,which is likely to cause low equipment utilization in the early stage and insufficient equipment capacity and poor reliability in the later stage.This article aims to study the multi-stage planning method of the integrated energy system to solve the problems caused by the single-stage planning.The main work of this paper is as follows:(1)The state parameter model of the generalized multi-energy network is established.First,the intensity and extension are used as the state parameters of the nodes and branches respectively to describe the energy transfer process in the wire or pipeline,and the transfer equations for the electricity,fluid and heat are derived;secondly,the energy conversion branch equation is established for energy conversion equipment,and the control methods of constant extensive quantity and constant intensity quantity are considered;finally,the network equation is established on the basis of the conservation law of node extensive quantity.This model is suitable for a cross-regional integrated energy system with a large supply range.(2)The energy flow model of the generalized multi-energy network is established.The nodes and branches are classified;the branch energy flow transfer equations are established for different branch types;the network equations based on the conservation law of node energy flow are established.This model is suitable for building-level integrated energy systems and park-level integrated energy systems with a small range.(3)Due to the above mathematical model,a multi-stage planning model of the integrated energy system is established.The objective function is to minimize the life-cycle cost including investment cost,operating cost and maintenance cost,and the constraints of each planning stage owing to the models above is set.The equipment or line configuration scheme in each planning stage can be obtained by mixed integer linear programming algorithm.Taking an integrated energy system to be built in North China as an example,a simulation analysis was carried out to verify the effectiveness and economy of the multi-stage planning.(4)A comprehensive energy system planning and calculation platform was designed and developed on the basis of the MATLAB GUI platform,including the login interface,the main interface and the result display interface with convenient use and intuitive interaction.It can realize the visualization of the research results in this paper,and provide a convenient and efficient calculation tool for planners in the meantime.