1.State Key Laboratory of Control and Simulation of Power System and Generation Equipments, Tsinghua University, Beijing 100084, China;2.Department of Electrical Engineering, Tsinghua University, Beijing 100084, China

The complementarity and coupling of various energy forms bring great value to the multi-energy system integration. However, different energy systems follow different physical laws and mathematical representations, which challenges the comprehensive analysis and coordinated optimization. Based on Laplace transform, a powerful tool for modeling the dynamic process of a system, this paper proposes a generalized electric circuit analysis theory for multi-energy networks. Firstly, a unified mathematical equation of heterogeneous energy flow in multi-energy networks is established, and the modeling method of generalized electric circuit is proposed based on the Laplace transform. The complex transmission characteristics of multi-energy networks in time domain are transformed into simple algebraic problems in Laplace domain, and the electric circuit model of distributed parameters for energy flow in each energy system is proposed. The lumped-parameter transmission model in branch layer is then proposed, which acts branch as the whole unit. The proposed branch model of generalized electric circuit can scientifically analyze the steady-state and dynamic characteristics of power flow in branch layer and reveal the commonness of energy flow of multi-energy networks, which lays the foundation for the full network analysis of multi-energy systems.