Online frequency estimation in power systems: A comparative study of adaptive methods

An experimental investigation of three adaptive algorithms for tracking the fundamental frequency in electric transmission grids is reported. An adaptive Prony´s method, an adaptive notch filter and an extended Kaiman filter have been presented in this paper. The design principles and the validity of the models have been sketched. For each method, appropriate models are presented and parameter adjustment guidelines are also proposed. The algorithms were developed in simple digital implementations compliant to real-time applications, therefore with low computational burden. Their performance have been evaluated and compared with the zero-crossing technique which serves as a reference. They have been designed especially for estimating frequency changes like small jumps and when the signal is corrupted with noise and other disturbances due to harmonics. The frequency estimators are compared on the basis of precision, transient response, and degree of noise and harmonics immunity.