Research On Optimal Configuration Of The Park-level Integrated Energy System Considering Off-design Characteristics

Nowadays,the increasingly severe energy crisis in the world has a profound impact on the economic and social development of all countries in the world.As an important and feasible solution to the energy problem,the integrated energy system has gradually attracted people’s attention.The integrated energy system can couple the production,transportation,transformation and consumption environment of non formal energy,realize the cascade utilization of energy,improve the comprehensive energy utilization rate,and have the potential to become the mainstream energy supply mode in the future.In order to further improve the operation efficiency of the integrated energy system and ensure the reliability of the comprehensive energy supply,this paper proposes a method of optimizing the configuration of the combined cooling heating and power system(CCHP)equipment and the electric energy conversion equipment,which takes into account the off-design characteristics.The specific research contents are as follows:Firstly,the integrated energy system structure with CCHP unit as the core and coordinated configuration of electric energy conversion equipment is proposed.Based on the energy coupling matrix of the integrated energy system,a multi energy flow model of the system is established.This paper analyzes the off design performance of CCHP units,presents the off-design characteristics(ODC)performance model and constant efficiency(CE)model of the main energy production and conversion equipment in the integrated energy system,and determines the efficiency matrix of the integrated energy system.Finally,the research on the system energy supply strategy under the scenarios of load fluctuation and peak-valley price is carried out,which lays the foundation for the follow-up research on the operation and planning of integrated energy system.Then,taking the lowest annual total cost as the objective function,a double-layer model of integrated energy system operation planning is established,which takes into account the off-design characteristics of equipment and the abundant energy supply.The transfer relations between the upper and lower models are given.Considering that the model is a mixed integer nonlinear programming model,this paper selects multi-objectives differential evolution(MODE)as a solution tool,then introduces the basic solution principle of differential evolution algorithm in detail,and shows the solution flow of the operation planning double-layer model.Finally,three simulation examples are set up for a park in Tianjin.The first example verifies the advantages of the joint configuration scheme of CCHP unit and electric energy conversion equipment proposed in this paper,and the benefits of considering its operation under off-design conditions in the equipment planning;the second example compares the differences between the system operation strategies based on the off-design characteristics model and the constant efficiency model,and verifies that the calculation of the operation economy is more accurate considering the off-design characteristics.And the operation of the system is more flexible and efficient.The third example verifies that the energy price and load scenario are the main factors affecting the integrated energy system equipment planning,and gives the boundary conditions of various equipment installation through calculation.