Extended Equal Area Criterion Revisited: A Direct Method for Fast Transient Stability Analysis

For transient stability analysis of a multi-machine power system, the Extended Equal Area Criterion (EEAC) method applies classic (EAC) concept to an approximate One Machine Infinite Bus (OMIB) equivalent system find critical clearing angle. The system-critical time can then be obtained by numerical integration OMIB equations. EEAC was proposed in 1980s and 1990s as substitute for time-domain simulation Transmission System Operators (TSOs) provide fast, with limited computational available those days. To ensure secure operation TSOs have identify prevent potential scenarios through offline analyses few dangerous ones. These days, due increased uncertainties electrical systems, number these is increasing, substantially, calling techniques once more. Among them, unique approach that provides not only valuable information, but also graphical representation dynamics. This paper revisits from modern, functional point view. First, definition model redrawn its general form. achieve analysis, relies on models true model. approximations are clarified, EAC redefined instability, conditions. Based defined conditions definitions, functions developed each building block, which later put out together full-resolution, scheme. scheme covers previous literature subject, allows introduce several possible new approaches detailed description their implementation procedure. A applied French EHV network, examined.