Cascading failure simulation and analysis method in integrated electric and gas system based on energy circuit

Cascading failures can be triggered within the closely interconnected Integrated Electric and Gas System (IEGS) due to the propagation of failures from either the power or gas system through their coupling components. Traditional cascading failure analyses typically involve time-domain modeling of the gas system, which is computationally complex and hinders the rapid study of failure propagation between subsystems. To address this issue, this paper proposes a novel cascading failure model of IEGS integrating a dynamic gas system model based on energy circuit (EC) in the frequency domain and a power system model based on steady-state DC in the time domain. First, considering the variable flow velocity of pipelines before and after a failure, a data fusion method for dynamic flow with multiple sets of flow velocity base values (FVBV) is proposed. Then, by modifying the original gaseous circuit matrix, the new network equations for the branch containing fixed-massflow-rate compressors are derived. Finally, a co-simulation approach for cascading failure analysis, featuring alternating flow calculations throughout the temporal domain, is established to investigate the propagation process of failures. Compared with the Finite Differential Method (FDM), numerical results demonstrate that computational efficiency is enhanced by over 10 times with the proposed method while meeting the required precision.