An Enhanced CWT-Based Approach for the Online Measurement of Low-Frequency Oscillations in Power Systems

In this article, a wavelet-based method for estimating inter-area oscillation parameters from phasor measurement units (PMUs) measurement data is proposed. The method takes advantage of approaches already available in the literature, such as the use of the modified complex Morlet (MCM) and the processing of transform coefficients according to linear regression. But the authors’ proposal introduces the following improvements that make the method suitable as a real-time support tool for the transmission system operator (TSO): 1) multichannel approach of the transform to improve estimation; 2) reduction of computational burden; and 3) real-time estimation of the oscillation amplitude (in addition to frequency and damping). The method was assessed through data gathered from real PMUs and compared with two traditional methods such as Tufts-Kumaresan (TK) and dynamic mode decomposition (DMD). The results show that the proposed method provides estimates as accurate as those granted by the two other approaches, but with a processing time of approximately 7 s, making it possible to track real time the evolution of oscillations.