Abstract:

In integrated energy systems （IES）， heat network transmission delay can readily cause supply-demand mismatch and energy efficiency loss， undermining system stability. To address this， a method capable of accurately characterizing network dynamic characteristics and effectively optimizing dispatch strategies was developed， to enhance both the economic viability and stability of IES. Initially， a multi-energy coupling model incorporating network dynamic characteristics was constructed based on the Modelica language， and the partial differential equations of the pipeline network and nodal algebraic equations were solved in a unified manner to accurately characterize the spatiotemporal coupling relationship of energy transmission. Subsequently， a two-stage optimization mechanism integrating "operational decision-making and simulation evaluation" was designed， where the dynamic model was used to optimize the day-ahead output schedule of heat sources， and a "thermal power imbalance rate" was introduced to quantify the impact of thermodynamic processes， thereby providing feedback correction for the scheduling strategy. Simulation was conducted based on an established thermal-electrical-gas IES model. The optimization results showed that， compared to the traditional static dispatch strategy （C-OS）， the proposed two-stage optimal dispatch mechanism （HTD-TSOS） significantly reduced the thermal power imbalance rate from 9.58% to 0.97%， effectively suppressing temperature fluctuations at the user end and markedly improving the quality of heat supply. Concurrently， the daily operational cost of the system decreased by approximately 10，400 yuan， yielding remarkable economic benefits. A comparative analysis on the dispatch results indicated that considering heat transmission delays had a profound impact on the output schedule of combined heat and power （CHP） units， whereas its effect on energy storage equipment was relatively minor. Ultimately， this method integrated IES optimal dispatch and network dynamic characteristic analysis into a unified framework， successfully overcoming the limitations of previous studies that treated these two aspects in isolation. The proposed HTD-TSOS significantly alleviated the supply-demand imbalance caused by heat transmission delay， effectively reducing system operational costs while enhancing users’ thermal comfort. This approach provided a highly practical and feasible solution for the optimal operation， efficient regulation， and scientific management of IES， offering valuable references for promoting the large-scale application of IES.

Key words: integrated energy system, multi-energy coupling, heat network transmission, two-stage optimization mechanism, thermal power imbalance rate, Modelica