Simulating sustained oscillations and ambient data in a large nonlinear power system model

This paper presents results of the time-domain simulation of sustained electromechanical and very-low frequency oscillations (VLFOs) using the full nonlinear model of the Brazilian Interconnected Power System (BIPS). The frequencies of simulated oscillations are close to those observed in actual synchronized phasor measurements. It is shown that VLFOs can be excited by inadequate parameters and nonlinearities in the turbine speed governors of generating units, and that their frequencies are close to natural frequencies of the linear model. The FDD and the N4SID methods were used to estimate the modal characteristics of these oscillations, and results were compared with those from eigenanalysis results.