Determining power system modal content of data motivated by normal forms

Models used to predict system response for disturbances often yield results that differ from recorded measurements. Engineers are tasked with improving system models to match important modal features of interest. These features are estimated from a given disturbance data set. The traditional linear system technique of Prony analysis has shortcomings when applied to nonlinear systems and noisy data. The work in this paper seeks to use knowledge of Normal forms analysis to improve upon Prony analysis in estimating modal content for nonlinear systems. Theory is presented and data from a three bus power system disturbance are analyzed.