The Spatial Statistics of Self-organized in Power System

Self-organized criticality (SOC) is one of explanation accepted so far on the mechanism of large blackouts. Based on the previous study on the temporal statistics of self-organized power system, the spatial statistics of the power system along its evolution is analyzed for better understanding of the mechanism of large blackouts. The conventional sensitivity method, Power Transfer Distribution Factor (PTDF), is used as the spatial weight matrix for the calculation of spatial auto correlation by Moran's I. An equivalent transmission capacity is defined as the observation. Besides Moran's I, mean, standard deviation and Entropy of equivalent transmission capacity are also provided for a better understanding of the effect of the evolution of transmission capacity on the system entering SOC, when large blackouts are of bigger possibility. IEEE -118 system is taken as a test system for the analysis. The analysis shows that spatial auto correlation by Moran's I is better for describing the heterogeneity of the power system and is a prospective candidate for the early warning of power system entering SOC.