# Integrated Energy System Optimization Based on Standardized Matrix Modeling Method
## 1 Introduction  
Traditional energy system planning usually only concerns a single energy system (such as cooling, heat, electricity, and natural gas) and cannot jointly optimize resources of each energy system, and therefore the overall energy resource utilization efficiency is low [1]. Regarding this problem, researchers proposed the concept of an integrated energy system in conjunction with distributed clean energy [2; 3; 4]. The integrated energy system is couples multiple energy sources, such as cooling, heat, electricity, hot water, and natural gas, to form a physical system for comprehensive conversion and utilization of multiple energy sources. It can fully utilize the complementary and synergistic effects of different forms of energy, and thus realize the optimal allocation of resources of different energy systems in a wider range and improve the flexibility and reliability of system operation, distributed clean energy consumption capacity, and system comprehensive efficiency [5]. [PERSON] et al. used the pattern search method and penalty function to optimize the operation strategy of distributed degeneration system with minimum annual operating cost as the objective function [6]. Based on the mixed integer linear programming theory, with minimum daily operating cost as the objective function, [PERSON] et al. constructed an operation planning model for distributed degeneration system, considering energy price, operation & maintenance cost, start-stop loss, ambient temperature, andother related factors [7]. [PERSON] et al. analyzed the conventional \"following the thermal load, FTL\" and \"following the electric load, FEL\" modes of distributed cogeneration system, and proposed a dynamic programming model for system operation optimization [8]. [PERSON] et al. analyzed the influencing factors of the comprehensive energy efficiency of multi-energy complementary distributed energy system, and taking the summer operating conditions as an example, the comprehensive energy efficiency levels under several typical configurations were listed [9]. [PERSON] et al. discussed the research progress of design optimization of distributed cogeneration system, and proposed a hierarchical framework for system optimization consisting of structural optimization, design optimization, and operation optimization [10]. Compared with the distributed cogeneration system, the integrated energy system optimization will be one of the main topics of current and future energy system engineering research due to the inherent diversity and complexity of the integrated energy system. In addition, although a large number of articles have discussed the design optimization and operation optimization of distributed cogeneration systems, few papers have studied their standardized modeling methods [11; 12]. Based on the scheduling factors, [PERSON] and [PERSON] proposed a modeling technique for automatically generating coupling matrices for small-scale cooling, heat, and electricity triple-supply system [13]; however, the integrated energy system planning model established is nonlinear due to the scheduling factors involved, and it will be too complex for a large-scale integrated energy system. [PERSON] and [PERSON] proposed a linear modeling method for the integrated energy system with an energy \"input-storage-conversion-storage-output\" structure [14]. However, this modeling method can only deal with the integrated energy system in the form of fixed structure. At present, it is of great significance to study a computerized standardized modeling method for the integrated energy system, which is applicable to different structural forms. In the paper, an effective and efficient standardized matrix modeling method and optimization method for the integrated energy system is proposed to solve the existing problems described above. The remainder of the paper is organized as follows.