Cost-effective power grid protection through defender–attacker–defender model with corrective network topology control

Power grid vulnerability is a critical issue in power industry. In order to understand and mitigate power grid vulnerability under threats, existing research often makes use of defender–attacker–defender (DAD) models to derive effective protection plans and evaluate grid performances under various contingencies. Corrective topology control (also known as corrective line switching) can be used as an operation to mitigate outages or attacks. In this paper, we propose to extend the traditional defender–attacker–defender model with the post-contingency corrective line switching operations as an effective post-contingency mitigation method. The proposed new model cannot be solved by existing algorithms used to solve the traditional defender–attacker–defender models because of the introduced binary transmission switching variables in the inner level problem. To solve this complicated DAD with transmission line switching (DAD-TLS) model, we customized and developed an exact algorithm based on the nested column-and-constraint generation (NCCG) algorithm, to compute global optimal solutions. A set of numerical studies on IEEE RTS one-area system demonstrate the significant improvements of power system resilience under malicious attacks due to line switching, and highlight that hardening plans derived from this new DAD model are much more cost-effective compared with those obtained from traditional DAD models.