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 multi-energy networks represented by power, gas and heat networks are one of the most complex physical networks in the world, which are also the key components connecting energy production and consumption, as well as the important way of the coupling of multi-energy systems. Based on the generalized electric circuit model of the branch layer in multi-energy systems, this paper proposes the generalized electric circuit analysis theory for the network layer. Firstly, according to the difficulty of representing the high-dimensional dynamic characteristics of multi-energy networks, a generalized modeling method for multi-energy networks in Laplace domain is proposed based on the generalized electric circuit model at branch layer, and the corresponding compact matrix model is also proposed. Secondly, external-port equivalent method of multi-energy networks is proposed, which can transform the complex internal information into equivalent boundary conditions to simplify the coordinated analysis of multi-energy networks and protect the data privacy of each energy system. Finally, combined with the practical characteristics of the heat network and the gas network, the generalized electric circuit model and the boundary equivalent method are proposed for the whole network with heat network and gas network.