A methodology for vulnerability assessment of backup protection under cascading failures

To avoid undesired operation of backup protection caused by load encroachment under cascading failures, the methodology for vulnerability assessment of backup protection is studied. In this paper, the vulnerability assessment of backup protections is formulated as a mixed integer nonlinear programming problem, which is solved by the binary particle swarm optimization approach. The measurement index for assessing the vulnerability of backup protection is given as well. The simulation results on New England 39-bus system demonstrate that the proposed method can effectively assess the vulnerability of backup protection under cascading failures.