Estimation of electromechanical modes under ambient condition via random decrement technique and TLS-ESPRIT algorithm

A method of estimating the electromechanical parameters using ambient data is presented in this paper. The approach consists of two steps: 1) using the random decrement technique (RDT) to get the free decay response from ambient data and 2) applying the TLS-ESPRIT algorithm to estimate the mode frequencies and damping ratios from these free decay responses estimated by RDT. The performance of the proposed method is compared with that of the RDT-Prony method using simulated data from the 16-machine test system and is seen to provide a more accurate estimation for damping ratios than RDT-Prony. The proposed method is further validated with PMU measurements from Sichuan power grid of China.