Abstract: The theory of self-organized criticality and entropy has been widely applied to complexity analysis of cascading failure in grids.By referring to relevant research achievements,an entropy evaluation index of branch circuit outage is proposed,and a new hybrid simulation platform of multi-time scale based on PSASP/UPI is developed to achieve a macro assessment of static security risk and its evolution trend.In the end,a simulation analysis of 7-machine 10-bus system verifies that the proposed indicators have greater advantage in reflecting fault behavior and micro heterogeneity as well as contributing to risk identification and vulnerability searching in power systems compared with the traditional power flow entropy index.