Research on wide area energy injection boundary of grid structure vulnerable interface

Power system structure vulnerability has still been further researched either on assessment method or on basic theory. The most distinct characteristic to show the vulnerability change is the change of absorbing ability when suffering from disturbance. However, the system absorption influences the size of energy injection region. In this paper, based on the structure preserved energy function model, the structure sensitive factor is first deduced which is used to classified the vulnerable interface. Then, the energy margin is used as the limitation and the energy injection region on vulnerable interface is researched, which can provide the direct theory to the vulnerable interface. The change of energy injection region during transient period is obtained with all the state information being obtained from PMU. The simulation results in 3-machine and IEEE-30 bus system show that the proposed method can not only detect the vulnerable interface, but provide the effective protective measurements. This will be valuable to improve power system security assessment.