Steady-State Security Region for Integrated Electricity and Heating System with An Optimization-Checked-Based Concave Hull Method

Steady-state security region (SSR) is a significant tool to facilitate the security issues in integrated electricity and heating systems (IEHS) since the deep coupling between the electric power system (EPS) and district heating system (DHS) increases the risks of cascading failure. However, the nonlinear and nonconvex nature of the SSR remains an obstacle to its efficient solution. This paper first comprehensively models the IEHS considering the dynamics of the coupling units and the DHS. Then, the SSR problem in the IEHS is formulated as two sets of nonlinear and sequential optimization problems to characterize the operational security boundaries. On this basis, a novel optimization-check-based concave hull method (OCCM) is proposed to efficiently and accurately solve the SSR problem. Numerical simulations are performed to verify the superiority of the proposed OCCM. The results highlight the influences of heating system integration on EPS's SSR and the impact of the dynamics on SSR computation.