Operation Optimization Of Integrated Energy System Using Unit Commitment Model

The grid connection of large-scale renewable energy has changed the operation and control mode of traditional power system,and the consumption of renewable energy will significantly affect the overall efficiency of the system.For the integrated energy system,it can improve the energy supply efficiency and the utilization rate of renewable energy through the reasonable integration of various energy supply systems.At present,the research on optimal operation of integrated energy system still has a large space for development.On the one hand,the coupling mechanism of multiple energy flows in the integrated energy system is very complex,and the mathematical problems of system operation are non-convex and nonlinear problems.Therefore,the operation of the integrated energy system is generally based on the unit commitment model.When there are a lot of different types of unit in the system,the unit commitment problem is often too complex and difficult to solve.On the other hand,for the dynamic optimization of the unit commitment model of the integrated energy system,the Mixed integral linear programming method is mostly used at present,but the models obtained by different linearization and constraint transformation methods have different expressions on the operation characteristics of the unit,so there will be some differences in the optimal operation results of integrated energy system.Therefore,this paper takes the integrated energy system as the research object and aims to improve the absorption capacity of renewable energy,and studies the dynamic optimization method of the integrated energy system based on the Unit Commitment Model(UCM).A Fast Unit Commitment Model(FUCM)for dynamic optimization of large-scale integrated energy systems is proposed.Mixed Integral Linear Programming(MILP)method is improved to solve complex unit combination models.The specific research contents of this paper include:(1)With the unit commitment model as the starting point,the traditional unit commitment model is firstly mathematically modeled,and then the Special ordered set method and corner method are used to transform the traditional model into a linear model,and the influence of different linearization methods on the dynamic optimization results of the integrated energy system is studied.The established unit commitment model is used to optimize the dynamic operation of a small-scale integrated energy system.By comparing the consumption level of renewable energy and the operating conditions of each unit in the system,the unit commitment model proposed in this paper is verified.The results show that the dynamic optimization method based on the unit commitment model proposed in this paper can significantly improve the solvability of the dynamic optimization problem of small-scale integrated energy system.At the same time,this paper also proposes an improved MILP model,which can greatly improve the computational efficiency while ensuring the solution accuracy of dynamic optimization.(2)The operation optimization problem of large-scale integrated energy system usually needs to include multiple types of units,and the optimization solution process needs to go through a large number of iterations,the solution process is cumbersome,and the cost of time and computing resources is huge.Therefore,based on the traditional unit commitment model,a fast unit combination model suitable for the dynamic optimization of large-scale integrated energy system is constructed by clustering the units with similar characteristics and using continuous variables to describe the dynamic characteristics of the units.In this study,the fast unit combination model was used to dynamically optimize the large-scale integrated energy system where West Inner Mongolia’s Power Grid is located.The dynamic operation characteristics of different types of units were obtained,and the grid-connected operation and consumption of renewable energy were optimized.