Assessment of spatial-temporal characteristics for disturbance propagation with combined FOPDT and Padé Approximant in large-scale power system

Abstract

In large-scale power system, the frequency response for disturbance exhibits spatial and temporal characteristics, of which a proper model for the propagation mechanism is not clear. In this paper, the disturbance power propagates along the transmission line and is treated as external excitations for the distributed generators. The dispersion of disturbance power causes the spatial-temporal features of frequency dynamics. The propagation is mainly divided into electro-magnetic and electro-mechanical stages. The process is modulated by the Kirchhoff laws and swing equation with the temporal and spatial distribution. The disturbance power, generators’ inertia and line parameter determine the propagation model. A combination of First Order Plus Delay Time (FOPDT) and Padé Approximant are proposed to extract the propagation delay. The mathematical solution of propagation delay is obtained for a one-dimensional ring system and a two-dimensional system. Numerical results are presented to verify the proposed models on a one-dimensional 32-machine ring system, two-area four-machine system and WECC-179 bus system.