In order to solve the problem that the current vulnerability assessments do not give enough consideration to the interaction among grids,an evaluation approach of interconnected district grid vulnerability was presented based on tie-line groups energy transmission.First,the inherent hierarchical structure and operational characteristics in the current district interconnected power grids were expounded.The features of black box data and the external grid dependence of the actual power systems were indicated.Then,the rationality of district grid vulnerability assessments based on tie-line groups energy transmission was analyzed.Secondly,the drawbacks of the two inherent vulnerability evaluation indices,i.e. node structure and branch load rate with weak macroscopic feature,were corrected by introducing two new indices,disturbance resistance and horizontal load rate indices.These two new indices focus on power disturbance and power exchange,which were not considered in the previous vulnerability assessment papers.And,an evaluation indices system suitable for actual power system was established.Then,the method of variation coefficients was used to evaluate the vulnerability of interconnected power grid based on tie-line groups energy transmission mode.Finally,the effectiveness of the evaluation was verified by the IEEE57 node system.
