Transient stability margin assessment for large power system using time domain simulation based hybrid extended equal area criterion method

A time domain based online dynamic security assessment (DSA) system requires fast and reliable method to calculate the stability margin. This paper presents the analysis of transient stability margin (TSM) using the extended equal area criterion (EEAC) method for a large power system for a given contingency for real-time applications. This paper also proposes a new method to identify the critical machine based on post-fault trajectory. The method has been tested on a realistic 20-generator 100-bus 256-branch reduced UK power system. A good assessment of stability limits was obtained.