Research On Evaluation Method Of Energy Supply Capability For Integrated Energy Systems

Energy is the cornerstone of the development of human civilization and scientific progress.However,the excessive consumption of energy has worsened the world environment and increased the global average temperature.In this context,how to improve energy efficiency and reasonably solve the contradiction between energy demand growth and carbon emission reduction is one of the main problems.The integrated energy system overcomes the existing mode,which the energy system planning and operating independently.It is conducive to realizing energy cascade utilization,improving energy supply efficiency and reducing carbon emissions.Developing integrated energy system is becoming the trend.At present,the technologies of integrated energy system have become a research hotspot in energy.Evaluating power supply capability is important for distribution network planning.It is also important to evaluate the energy supply capability for integrated energy systems(IESs).For the IESs has been constructed,evaluating its energy supply capability is helpful to find energy supply bottlenecks and introduce optimization strategies.For the IES to be constructed,evaluating its energy supply capability can determine the validity of planning schemes.Therefore,evaluating energy supply capability is of great significance to the planning and construction of IESs.The existing energy supply capability methods take N-1 guildline as security constraint.It is not conducive to develop the potential of energy supply.Besides,the factors such as integrated demand response are not fully considered in the existing method.In this regard,this paper evaluates the energy supply capability of the integrated energy system with reliability as the security constraint and considering the comprehensive demand response and load development uncertainty,taking the integrated energy microgrid and regional integrated energy system as the research object.The main work is as follows:(1)Taking the integrated energy station as research object,an energy supply capability evaluation method is proposed,using reliability as security constraint.First,the architecture of integrated energy station is described based on the energy hub model.Secondly,the energy supply capability considering and not considering faults are described,the state space and reliable energy supply interval model are constructed,and the relationship between load scale and reliability is analyzed.On this basis,the interval boundary solution method based on NSGA-2 is proposed.Finally,the case study results show that the supply capability of all types of energy are negatively correlated with each other.When the reliability constraint becomes more strict,the energy supply capability of all types of energy will be reduced.(2)Furthermore,taking the regional integrated energy system as the research object,an energy supply capability evaluation method is proposed,considering reliability constraint and integrated demand response.First,the architecture of regional electricity-heat integrated energy system is described.The input is the power grid.The integrated energy station is the coupling node between distribution network and heat supply network.Heat is transformed by electricity and supplied to users through heat supply network.Secondly,the reliable energy supply interval model is constructed,considering reliability constraint and integrated demand response.The mathematical properties of the reliable energy supply interval are proved.The influencing factors of the interval boundary are analyzed.A solution method of the maximum energy supply capability and the boundary of the reliable energy supply interval is proposed.On this basis,a rapid evaluation method of operating point reliability is proposed.The energy supply margin and operation risk of the system is quantified.Finally,the case study results show that the regional integrated energy system not only has a negative correlation with the supply capability of each energy,but also has a negative correlation with the supply capability of each feeder and pipeline.(3)Focus on the relationship between reliability constraint,participation ratio of integrated demand response and energy supply capability from the perspective of economy,an optimal load carrying capability evaluation method is proposed,considering the uncertainty of load development.First,considering the difference of load characteristics of different users,the concept of load carrying capability is proposed.An interval model of load carrying capability is constructed,describing the supply capability of the system to various loads.The interval boundary characteristics of load carrying capability are analyzed.Secondly,a double-layer optimization model for the evaluation of the optimal load carrying capability is constructed.The upper model aims at the optimization of the benefit of load carrying capability,demand response cost,and energy shortage cost.The benefit of load carrying capability is obtained according to the benefit and corresponding probability integral of all possible future scenario.The lower model is the calculation of the maximum energy supply capability.On this basis,the calculation of reliability and demand response cost are linearized.The upper model is solved by genetic algorithm and the lower model is solved by CPLEX.Finally,the case study results show that if the load characteristics of various users are complementary,the load carrying capability will be greater than the energy supply capability.When the reliability of one energy resource reaches the upper limit of the reliability constraint,load carrying capability will not increase with further relaxation of the reliability constraint of other energy or increasing demand response ratios.It is important to reasonably configure reliability constraint and integrated demand response ratios.