In view of the disadvantages of the traditional energy supply systems, such as separate planning, separate design, independent operating mode, and the increasingly prominent nonlinear coupling between various sub-systems, the production, transmission, storage and consumption of multiple energy sources are coordinated and optimized by the integrated energy system, which improves energy and infrastructure utilization, promotes renewable energy consumption, and ensures reliability of energy supply. In this paper, the mathematical model of the electricity-gas interconnected integrated energy system and its state estimation method are studied. First, considering the nonlinearity between measurement equations and state variables, a performance simulation model is proposed. Then, the state consistency equations and constraints of the coupling nodes for multiple energy subsystems are established, and constraints are relaxed into the objective function to decouple the integrated energy system. Finally, a distributed state estimation framework is formed by combining the synchronous alternating direction multiplier method to achieve an efficient estimation of the state of the integrated energy system. A simulation model of an electricity-gas interconnected integrated energy system verifies the efficiency and accuracy of the state estimation method proposed in this paper. The results show that the average relative errors of voltage amplitude and node pressure estimated by the proposed distributed state estimation method are only 0.0132% and 0.0864%, much lower than the estimation error by using the Lagrangian relaxation method. Besides, compared with the centralized estimation method, the proposed distributed method saves 5.42 s of computation time. The proposed method is more accurate and efficient in energy allocation and utilization.

鉴于传统能源供应系统的缺点，例如单独计划，单独设计，独立运行模式以及各个子系统之间日益突出的非线性耦合，需要协调多种能源的生产，传输，存储和消耗并通过集成能源系统进行了优化，从而提高了能源和基础设施的利用率，促进了可再生能源的消耗，并确保了能源供应的可靠性。本文研究了电-气互联综合能源系统的数学模型及其状态估计方法。首先，考虑测量方程与状态变量之间的非线性，提出了一种性能仿真模型。然后，建立了多个能源子系统耦合节点的状态一致性方程和约束条件，并将约束条件放宽到目标函数中，以对集成能源系统进行解耦。最后，通过组合同步交变方向乘数法形成分布式状态估计框架，以实现对集成能源系统状态的有效估计。油气互联集成能源系统的仿真模型验证了本文提出的状态估计方法的有效性和准确性。结果表明，所提出的分布状态估计方法估计的电压幅度和节点压力的平均相对误差仅为0.0132％和0.0864％，远低于拉格朗日松弛法的估计误差。此外，与集中估计方法相比，该分布式方法节省了5.42 s的计算时间。所提出的方法在能量分配和利用方面更加准确和有效。