Identification of Cascading Failure Initiated by Hidden Multiple-Branch Contingency

In past studies on cascading failure assessment, the risk of N - x initiating contingencies (ICs) regarding their initiating effect and hidden contingency risk (a high-risk x-component outage sequence within the IC) may not be fully investigated, which may underestimate the risk of IC-triggered cascading overload failures (COFs). In addition, the research on the efficient screening of N - x IC (x ≥ 2) and the identification of the cascading with the largest system impact is limited. To undertake this challenge, this paper proposes a COF identification approach (CIA) which integrates the IC screening and the COF identification for finding the high-impact COFs initiated by N - x ICs with hidden risks. The CIA is validated by simulations on the IEEE 118-bus system. The simulation results demonstrate that the CIA can efficiently screen out the high-risk N - 2 and N - 3 ICs that have an optimal outage sequence and trigger COF chains. The results also show that the CIA can identify the IC-triggered high-impact COFs and quantifies their impacts. The approach can be used as either a cascade-triggering event screening tool (by applying the IC screening module) or a COF risk assessment tool for ensuring system reliability.