ANALYSIS OF INTER-AREA OSCILLATIONS VIA NON-LINEAR TIME SERIES ANALYSIS TECHNIQUES

This paper compares the characteristics and information provided by different modal identification tools, in the analysis of a very complex forced inter-area oscillation problem recorded in the Mexican intercon- nected system. These oscillations involved severe frequency and power changes throughout the system and resulted in load shed- ding and the disconnection of major equipment. This pa- per reports on the early analytical studies conducted to examine the onset of the dynamic phenomena. Instances of variations in the amplitude and frequency of the excited inter-area modes are investigated and per- spectives are provided regarding the nature of studies required to identify and characterize the underlying nonlinear process. It is shown that nonlinear analysis tools are able to identify aspects of the dynamic behavior of the system that are needed in the validation and characterization of the observed phenomena, even in cases where power system dynamic characteristics change several times due to load shedding and generation tripping operations.