Comparison of ring-down response estimation between RDT and NExT under ambient condition

This paper describes two data driven methods to extract the ring-down signatures of the random responses for the study of low frequency electromechanical oscillations. The two methods are: random decrement technique (RDT) and the natural excitation technique (NExT). The objective is to compare and contrast the performance of the methods. The correlation coefficients between the extracted ring-down signal and the impulse signal, the accuracy of damping ratio and frequency estimated by RDT-ERA method and the NExT-ERA method are the measures of the performance of the algorithms. Their performances are evaluated using an ideal second-order system, and PMU measurements from Sichuan power grid of China.