Cascading Failure Analysis Of Grid-connected Photovoltaic(PV)Power System Based On The Complex Network Theory

Large area blackout is generally caused by cascading failure. The complex network theory can reflect system inherent connection and operating characteristics from the macroscopic angle besides its simple model structure, thus it’s used for the study of power system cascading failure. There is no doubt that more and more photovoltaic(PV) power will be integrated. The fluctuation of PV power is the latency of grid cascading failure, it may bring a new challenge to the safe operation of the grid. So it is necessary to apply the complex network in cascading failure study, especially finding the vulnerability link of the network.The topological principle and method is firstly proposed according to the characteristics of grid-connected PV power system, as well as the complex network model is built.The cascading failure models of the conventional power system and grid-connected PV power system are separately constructed, while the power flow is considered as the basic load. The grid sensitivity of conventional fault mode is analyzed according to different power flow calculation methods. The influence of grid caused by the PV fluctuation and conventional fault is compared, while the influence of cascading failure caused by grid-connected PV is quantified by evaluation indexes.At last, the critical nodes and edges of the network are identified for the determination of the vulnerable region, through the statistical characteristic analysis of the degree, clustering coefficient, the electrical distance, electric betweenness and so forth. Advantages of large capacity integration point can be seen through the analysis. Research of the IEEE30bus system is also taken, in which the statistical characteristic of grid-connected PV power system is analyzed, and the critical components of the network are identified, the work means a lot to the failure defense realistically.