Abstract:

 To improve the power supply reliability of power system and reduce the incidence of large-scale cascading failure, this paper presented a new line importance degree evaluation index for the propagation of cascading failures, which was used to quantify the impact of transmission line fault on cascading failure propagation. According to the evaluation results of line’s importance degree, this paper proposed the matching model of transmission capacity, which could reasonably configure the transmission capacity of system, and optimize the load rate distribution of system, so as to improve the power supply reliability of power system. The simulation experiment results show that in the case of transmission capacity redundancy （the same overall load rate of system）, the transmission capacity matched in the proposed optimization model or the adjustment of load rate distribution can prevent the evolutionary trend of load rate to heterogeneous distribution during fault propagation process, so as to reduce the risk of large-scale cascading failure.

Key words:  heterogeneity characteristics, importance degree evaluation, matching model, cascading failure, self-organized criticality, transmission capacity