Generalized Equal Area Criterion for Transient Stability Analysis

In power system fields, the Equal Area Criterion is of great educational importance on revealing the sufficient condition for a grid-connected synchronous machine to maintain its transient rotor angle stability under a disturbance. However, the criterion faces big challenges in stability analysis for either multi-machine power systems or increasing renewable generators that have nonlinear characteristics very different from synchronous machines even if still modeled as oscillators in the grid. This paper proposes a Generalized Equal Area Criterion for quantitative stability analysis of a more general, nonlinear oscillator under a large disturbance. Such a nonlinear oscillator can either model a renewable generator or represent an equivalent oscillator on dominant inter-area oscillations of a multi-machine system. The new criterion is tested for transient stability analysis of single-generator-infinite-bus system and an NPCC 140-bus 48-machine system.