An Investigation on the Applicability of the Integrated Method for Multi-Carrier Energy Flow Analysis

The integrated energy system (IES) combined with electricity and heat networks is a research hotspot in energy field in recent years. As the foundation of security and economy analysis of IES, the steady-state multi-carrier energy flow (MEF) analysis is important but difficult to converge. An integrated method for solving MEF has been presented and adopted in some published literatures. In this paper, we investigate the integrated method and point out its two problems: one is the failure of the integrated method when energy reverses during iteration in some exceptional cases; the other is the high sensitivity of the method to the initial value. Thereafter, the fundamental causes for the two problems are revealed. Moreover, we modify the integrated method based on the fundamental causes to deal with the two problems. The cost and benefit of the modified integrated method are analyzed as well. Finally, the integrated method and the modified integrated method are discussed on the basis of theoretical and simulation results. The results show that with fewer iteration times and less calculation time, the modified integrated method has better applicability to exceptional cases and less sensitivity to the initial value.