Weighted directed graph based matrix modeling of integrated energy systems

Abstract The integrated energy system (IES) has attracted great attention for its significant role in energy efficiency improvement, energy conservation and emission reduction, in which the modeling naturally becomes a hot topic in related fields. In this study, a matrix modeling method based on graph theory is proposed for the multi-energy flows of IES, where the energy converters and subsystems are abstracted into branches and nodes so as to construct a weighted directed graph model of IES with the establishment of an energy balance equation. Energy storage devices are also integrated into the proposed method by defining virtual storage nodes and charging/discharging branches, and the model of IES is established in a unified matrix form. In case studies, the superiorities of the proposed method in complexity, computational efficiency and flexibility are demonstrated in comparison with a number of state-of-the-art approaches. The computational burden of the operational optimization for the IES including energy storage devices is significantly reduced, and the economic benefits of various energy storage devices are evaluated.