Two-Stage Convexification-Based Optimal Electricity-Gas Flow

This paper develops an optimal electricity-gas flow (OEGF) framework considering power line and pipeline congestions to coordinate the energy supplies, flexible electricity and gas loads, electricity and gas storages within an integrated electricity and gas system. The objective is to maximize the social welfare, while balancing the supply and demand, and relieving the congestion. The formulated OEGF with nonlinear power/gas flow models is a nonlinear programming (NLP) problem. In order to improve the computational efficiency of OEGF and guarantee the accuracy of solutions, a modified DC power flow model embedded power losses is adopted to model the power system for simplification first; two different two-stage convexification methods are then designed to address the nonlinear OEGF model. The obtained two types of OEGF models are convex in both stages and can be easily solved. Numerical results validate the effectiveness of the proposed two OEGF methods compared to the nonlinear OEGF method. In addition, effects of congestion management are also investigated.