Application of Weighted Structured Total Least Squares in Identification of Power System Oscillation Modes

In this paper we present a novel method for estimating electromechanical modal parameters from noisy signals recorded during power system disturbances. The method is based on the weighted Structured Total Least Squares (STLS) approach for parametric signal modelling. Compared to Prony´s method, the weighted version of STLS method is less sensitive to noise and trend components in recorded signal samples. It is shown through practical examples that the method displays high resolution in parameter estimation for some difficult cases with close modal frequencies, using only short signals recorded by Digital Fault Recorder.