Fractional Order Modeling of Thermal Circuits for an Integrated Energy System Based on Natural Transformation

Abstract

With the development of the economy, energy systems have become the focus of academia and industry. The integrated energy system formed by electricity, gas, and heat networks can improve the utilization efficiency of energy. Heating networks in integrated energy systems play an important role. The consideration of the dynamic characteristics of the heating network can improve the flexibility of the system and reduce the operation cost of the system. In this paper, a thermal circuit model is derived for the heating network from an electrical-analog perspective. Based on the thermal circuit model, the fractional-order model of the thermal circuit is proposed. The Adomian polynomial decomposition method based on natural transformation is used to solve the model. The losses and transfer delays of the heating network are obtained. The computing time is about 0.5 s and the relative error is less than 0.02%. The results show that the thermal circuit analysis theory can describe the complex dynamic characteristics of heating network and that the calculation procedure is simple, fast, and accurate.