Time-frequency atom filter based scheme for online monitoring of low frequency oscillations

A novel method for online monitoring of the low-frequency oscillation is proposed in this paper. Several time-frequency atom (TFA) complex band-pass filtering units (CBFU) are placed in parallel to cover the low-frequency band. By concurrent filtering calculation, the mode parameters including magnitude, frequency and attenuation factor can be obtained. Further the Particle Swarm Optimization (PSO) has been utilized for estimating DC component and initial phase angle. The band and observation time window of each CBFU can be adjusted flexibly, hence, by adjustment, higher mode resolution and shorter time window can be achieved. By test, the running time is given showing the proposed method is fast enough for online purpose. To verify the performance, a set of simulation tests based on MATLAB and EMTDC/PSCAD are presented. And the goodness of fit is introduced as a measure of accuracy. The results show that the proposed scheme has robust colored Gaussian noise rejection and is able to accurately extract critical mode parameters from both stationary behavior and evolving dynamics in oscillations with superior mode resolution and fast dynamic response.