Expansion Planning Of Integrated Energy System Considering Wind Power Access

Energy is the cornerstone and key of the sustainable development of society,and under the increasing pressure of energy consumption and environmental pollution,the balance between energy supply and demand is becoming serious gradually.Integrated energy system(IES)including electricity,gas,heat systems,has widely attracted interest because of its higher energy supply efficiency and operational flexibility.Furthermore,the flexibility of IES can also be used to provide more adjustment space for volatile renewable energy such as wind,solar and other sources.In other words,the cooperative operation of multiple energy improves the accommodation ability of renewable energy and realizes the complementation of multiple energy system.Therefore,IES,which has multiple complementary advantages,will become one of the primary forms of the energy supply in the future.However,due to the complexity of deep coupling between multiple energy and the severe uncertainty brought by large-scale wind power access,the IES planning and operation will face significant challenges as same as traditional power system.Therefore,this paper focuses on the deeply coupled IES expansion planning of power system,natural gas system and thermal system.On this basis,the emphasis is put on how to grasp the uncertain characteristics of wind power accurately and reasonably in order to deal with the impact of wind power uncertainty on integrated energy system planning,and achieve maximum economic benefits.The main work of this paper is described as follows:First of all,the concept of energy hub is used in this paper to present a unified description and expression model of key coupling sector in integrated energy system.The mathematical models of energy coupling equipment(CHP,gas furnace and PTG)are shown,including mathematical expressions of physical quantities and economic quantities(investment costs,fuel costs,and maintenance costs).Energy hub is the most basic and key sector of multiple energy conversion,which will play a fundamental role in the modeling and analysis of the later integrated energy system planning problem with wind power.Secondly,the scenario method is used to express the wind power uncertainty,and an IES expansion planning method with wind power is proposed.In order to enable IES to meet the load requirements in the whole planning period economically and reliably,it is necessary to carry out the research on IES expansion planning with wind power.On the basis of the existing operating equipment in the system,it is important to decide whether and when the candidate equipment will be put into operation during the planning period,including the location of each equipment and the expansion of energy transmission network.In planning decision-making,a series of typical wind power values with probability information are used to express the uncertainty of wind power,and a scenario-based IES expansion planning model with wind power is constructed.Furthermore,based on the limited amount of scenarios after reduction,a two-stage solving strategy based on scenario method is proposed in this section,aiming to solve the problem directly and efficiently.Finally,based on the above-mentioned research,an IES expansion planning model based on wind power probability interval is proposed.In terms of the stochastic expression of wind power,the interval method is more applicable to the medium-and long-term scale planning than the single point power value.CVaR(Conditional Value-at-Risk)is used to express the wind curtailment and unserved energy risk caused by wind power uncertainty.Furthermore,the corresponding relationship between wind power acceptance interval and CVaR is established,and the probability level confidence value corresponding to the acceptance interval is obtained by optimizing the IES planning model.At the same time,the electricity storage system is introduced to mitigate the fluctuation of wind power,and it can also mitigate the excess or shortage of wind power by charging and discharging.Through above process,the storage system can ensure the stable operation of the system and improve the flexibility and reliability of the operation of the system.In order to improve the efficiency and feasibility of the model,the piecewise linearization method is used to deal with the nonlinear integral term of CVaR,and GAMS/CPLEX is used to solve the nonlinear integral term.The effectiveness of the proposed model is verified by the analysis results of an example.In this paper,the expression and analyze method of wind power uncertainty in the expansion planning of integrated energy system are preliminarily explored,which promotes the cooperative planning and operation ability of integrated energy system and renewable energy,and improves the economic benefit of the system.