Adaptive estimation of wide range frequency changes for power generator protection and control purposes

A method and a detailed adaptive algorithm for wide-range frequency change measurement is presented. The method is based on a two-stage operating principle in which the results of a coarse frequency measurement are used for both orthogonal filter adjustment and modifications to the basic algorithm that is applied to fine frequency estimation. The adaptive features ensure good selectivity of the algorithm (in the sense of higher and subharmonic attenuation) within the range 5 to 80 Hz. Simulation results presented confirm good accuracy of frequency estimation in the presence of a standard noise level in the input signal, as well as satisfactory frequency tracking properties of the algorithm at relatively high frequency-changing rates