Analysis on Grid Structural Vulnerability Based on Optimal Branch Limit

According to the relationships among the change of generator production, energy margin and change of branch power flow, the combination of production change of all generators and the upper and lower limits of branch restriction are first computed by the non-linear programming. And then, based on the branch restriction, the assessment indexes of branch vulnerability are founded. One of the advantages of this research is that the upper and lower limits of branch restriction can be updated timely. In addition, because of the synthetical efficiency of multi-generators, the branch vulnerable characteristics may not change with the common trend. Therefore, when the energy margin is used to compute the branch limit, the branch power flow is admitted to change with the unspecific generator, it is helpful to further analyze the vulnerable characteristics of grid. At last, the simulations in IEEE-30 bus system demonstrate the validity and feasibility of the approach proposed.