Transient Stability Analysis of Multi-Machine Power Systems Based on Sum of Squares Programming and Coherency Dynamic Equivalents

Transient stability analysis (TSA) of large-scale power systems is one of the most computationally significant tasks. To reduce the difficulty of this task, this paper uses a coherency-based dynamic equivalent method to obtain the aggregation model of multi-machine systems, which is a valid approach to reducing the size of power system model. Based on this aggregation model, the expanding annular domain (EAD) algorithm based on sum of squares (SOS) programming is employed to estimate the domain of attraction (DA) of the aggregation model, which provides an approximate description of transient stability of the original system model. The validity of our proposed methodology is illustrated on a 15-machine 73-bus system. Simulation results show that the proposed method can provide better estimates in terms of DA and critical clearing time (CCT) for large-scale power systems.