Manifestation Of Significant Impact Of Grid Structure On Characteristics Of First Swing Dynamics

In this paper, we study the significance of the impact of grid structure on first swing dynamics. Particularly, the dynamics are characterized with the total transient energy injected into the power system during the fault period. Two methods are used to evaluate the total transient energy. One method is to use the representation of the total transient energy in terms of grid-structure-related variables, and the other method is to use time domain simulations. In a real power system, we investigate the correlation between the total transient energy predicted using the structural representation and the one evaluated using time domain simulation with various scenarios taking into account different generator models, load models, and operating conditions. It is found that there is a strong correlation between the evaluation results using the two methods, and the strong correlation does not change significantly with generator models, load modes, and operating conditions. Moreover, we further quantitatively analyze the discrepancy of the evaluation results obtained by the two methods. It is found that the discrepancy is small for most critical fault locations. The structural representation is useful for fast screening potential critical fault locations in large-scale power systems. The findings can be considered as a manifestation of the significant role of grid structure in characterizing first swing dynamics.