Full-cycle dynamic security region for the integrated electricity-gas energy systems

The growing interdependence of the electric power system (EPS) and the natural gas system (NGS) has led to frequent cascading failures between the two systems in recent years. The study of the security region for the integrated electric and gas system (IEGS) is the key approach to prevent such incidents. However, the security region method is developed based on the static operating characteristics of the EPS, which limits its applicability to the IEGS with dynamic gas flow and line-pack storage characteristics. To address this issue, this paper proposes the concept of the dynamic security region (DSR) for the IEGS, and develops a set of DSR optimization models, which are capable of accurately portraying the dynamic evolution of the IEGS safety margin with gas flow diffusion. The DSR is founded upon the high-accuracy dynamic gas flow model, which is solved using a threestage leapfrog finite difference method (TL-FDM). An improved orbital rotation method is proposed to approximate the DSR boundary. On this basis, a full-cycle DSR rolling optimization solution algorithm is developed. Case Studies demonstrate the effectiveness of the proposed method and verify that it significantly improves the reliability of the system operation.