综合能源系统具有高灵活性的优势，并有望在未来的高比例可再生能源消纳与能源系统转型过程中发挥重要作用。为推进综合能源系统的建设与广泛应用，综合能源系统的运行优化与设计优化研究具有重要意义。然而，随着大量具有强烈波动性的可再生能源的并入，综合能源系统在运行过程中可能面临部件运行工况显著偏离设计工况的问题，进而引发系统运行性能的显著变化；此外，由于耦合了各种动态特性差异显著的系统部件，综合能源系统的动态特性极为复杂，这也极大增加了系统灵活性刻画的难度。上述的这些系统特点，都为综合能源系统的研究带来了巨大挑战。当前综合能源系统的优化研究由于时间分辨率精细度不足与系统动态特性考虑不足，无法对系统的灵活性进行准确刻画，进而可能导致系统可靠性不足、经济性差等问题，严重制约了综合能源系统优势的充分利用。本研究聚焦于综合能源系统的运行与设计优化这一关键问题，通过系统性的研究工作，深入探讨了多个关键领域。具体而言，研究内容涵盖了关键系统部件的变工况建模、综合能源系统的动态建模、多时间尺度的运行优化、变时间分辨率设计优化方法的提出，以及考虑灵活性改进的系统设计优化等多个方面。这些研究成果为综合能源系统的高效运行与科学规划提供了系统性的方法与策略，对于推动能源系统的可持续发展具有重要的理论价值和实践意义。主要研究成果包含以下四个部分：其一，建立了考虑变工况特性与动态特性的综合能源系统模型，有效提升了对于综合能源系统变工况特性与动态特性刻画的准确度；其二，提出了考虑系统动态特性的综合能源系统多时间尺度运行优化方法，充分运用热网的动态特性促进了可再生能源利用率提升约4个百分点，并提高了系统应对可再生能源预测误差的能力以提升系统运行经济性约4.99%；其三，提出了一套综合能源系统变时间分辨率设计优化方法，在系统规划阶段实现了运行与设计一体化的优化计算，提高了对系统灵活性刻画的准确度，进而消除了系统运行中的失负荷情况，并降低了燃煤机组寿命损耗约12.4~13.9%，降低了度电碳排放约0.94%；其四，以“风光火储热”综合能源系统的改造建设为研究背景，通过情景对比分析的方法，深入探讨了低负荷改造与热网储能利用两种灵活性改进方法的作用效果与规律，为传统燃煤电厂向综合能源系统转型的路线与方案选择提供了决策依据。

Integrated energy systems, characterized by their high flexibility, are expected to play a significant role in the absorption of renewable energy and facilitating the low-carbon transformation of energy systems in the future. To advance the construction and application of such systems, research on the operation optimization and design optimization of integrated energy systems is of great importance. However, the integration of a large amount of renewable energy with strong fluctuations poses substantial challenges. During the operation of integrated energy systems, the operating conditions of components may significantly deviate from the design conditions, leading to notable changes in system performance. Moreover, the coupling of various system components with distinct dynamic characteristics introduces significant complexity to the system, greatly increasing the difficulty of accurately depicting system flexibility. Both of the characteristics mentioned above present substantial challenges for the optimization research of integrated energy systems. Current researches often fails to accurately represent the system flexibility due to the adoption of inadequate time resolution and insufficient consideration of system dynamics. This limitation could potentially lead to issues such as reduced system reliability and poor economic performance, thereby hindering the fully realization of the advantages of integrated energy systems.This dissertation focuses on the key problem of operation and design optimization of integrated energy systems, exploring multiple crucial areas through systematic research. Specifically, the main research content includes off-design modeling of key system components, dynamic modeling of integrated energy systems, multi-timescale hierarchical operation optimization of an integrated energy system, the development of the variable temporal-resolution design optimization method, as well as design optimization of an integrated energy system considering various flexibility enhancement methods. The research results offer systematic methods and strategies for operating and designing integrated energy systems, making a significant contribution to the sustainable development of energy systems.The main research achievements include four parts: Firstly, an integrated energy system model considering off-design condition characteristics and dynamic features of the system components is established, which significantly improves the accuracy of characterizing the system performance. Secondly, a multi-timescale hierarchical operation optimization method for integrated energy systems that considers system dynamics is developed. This method could efficiently utilize the dynamic characteristics of the heat network to promote the utilization rate of renewable energy by about 4 percentage points, as well as effectively compensate the prediction errors in renewable energy to enhance the economic efficiency of system operation by about 4.99%. Thirdly, a variable temporal-resolution design optimization method for integrated energy systems is developed, which could enhance the accuracy of system flexibility characterization by integrating design and operation optimization during the system planning phase. This, in turn, improves the accuracy of system flexibility description, eliminated the loss of load during system operation, reduces the loss of life of coal-fired units by about 12.4~13.9%, and reduced carbon emissions per unit of electricity by about 0.94%. Fourthly, focusing on the construction of an integrated energy system combining wind, solar, thermal power, and energy storage systems, scenario-based comparative analysis is conducted to further summarize the effects of the two flexibility improvement methods, deep peak shaving transformation and thermal network energy storage utilization, which could provide guidance for the construction and renovation of integrated energy systems in the future.