Methodology for Analyzing the Flexibility of Integrated Energy Systems Considering gas Pipeline Inventory

The integrated energy system(IES) has great flexibility, and the gas subsystem, as an important flexibility resource in the IES, its refined modeling will play a crucial role in accurately assessing the flexibility of the IES. In view of this, a methodology for analyzing the flexibility of the IES which considerated the gas pipeline inventory model is proposed. Firstly, the pipe storage effect of gas in the IES is considered, and the partial differential equation of the gas flow process is transformed into the Weymouth equation in algebraic form by the finite difference method, and the nonlinear constraint in the equation are linearized by using the second-order cone relaxation; Secondly, from the perspective of the superior power system, the overall flexibility assessment model of the IES taking the integrated demand of the IES to the superior power and gas as a quantitative index is established taking into account the gas pipeline inventory model, which quantifies the effect of complementary coupling of electric power in the IES with the help of the electric-gas feasibility domain.