Fast decomposition of energy flow for integrated electricity and gas systems

This paper introduces a novel mathematical approach for analyzing energy flow in Integrated Electricity and Gas Systems (IEGS) within distribution networks. Although the non-convex nature of natural gas flow has traditionally been handled using second-order cone programming (SOCP), SOCP-based formulations suffer from reduced computational efficiency and solver compatibility issues as system scale increases. To address these challenges, this paper proposes a Taylor series-based first-order linear approximation method that maintains linearity, thereby enabling faster computation and better compatibility with standard optimization solvers. Despite its iterative nature, the proposed method exhibits rapid and accurate convergence. Validation was conducted on several test systems, including the radial IEEE 33-bus/33-node system, a meshed IEEE 8-bus/8-node gas network, and the large-scale IEEE 118-bus/118-node system. Simulation results demonstrate that the proposed approach achieves higher approximation accuracy and faster computation compared to conventional SOCP-based methods, confirming its effectiveness for practical IEGS operation analysis.