Based on the basic principle of Theil’s entropy measure and system voltage level

a critical node identification method is proposed for power grid

which comprehensively considers the node static voltage stability and distribution equilibrium of branch transfer power flow. According to the influence mechanism of load variation on system voltage amplitude growth and transmission power flow variation

the Theil’s entropy model of voltage growth rate and the Theil’s entropy model of weighted flow impact rate are built to describe the equilibrium of system voltage growth and power flow variation. The weight analysis method combined with binary feature analysis method and entropy weight method is adopted to integrate the indexes

and thus the comprehensive evaluation index with the consideration of both the subjective preferences and the objective data is obtained to accurately identify the critical node. The simulative results of IEEE 30-bus system and a real regional southwest power system verify the validity of the proposed model.