Steady-State Security Region Considering Post-Contingency Cascaded DC Commutation Failure

With the enhanced interaction between the AC and DC power system, the post-contingency cascaded DC commutation failure (CF) has been a potential security risk. This paper proposes the steady-state security region (SSR) formulation with the post-contingency cascaded CF considered. The voltage reduction at the post-contingency quasi-steady-state is selected to identify the cascaded CF. The decoupled linearized power flow (DLPF) is introduced so that the voltage issues can make contributions to the SSR depiction. The proposed SSR provides the scope of the dispatch decisions where the cascaded CF can be inhibited. Case studies between different types of SSR are performed in the IEEE modified 9- and 30-bus test systems to validate the effectiveness of the proposed SSR.