Adaptive estimation of frequency in power networks

A common problem in power networks is the estimation of the fundamental frequency of harmonic signals. The authors propose and examine two related methods that use the autoregression as an underlying model, avoid the estimation of its parameters, and determine the fundamental frequency directly. They are intended to operate on signals which, besides the fundamental, may contain harmonic components. In addition, they should operate in high signal-to-noise ratio environments. They are adaptive in nature and do not require heavy computations. The methods are parametric and are based on the fact that n real sinusoids can be represented by a linear difference equation with constant coefficients. The order of the equation of 2n and its coefficients are characterized by a special symmetry. Simulation results are provided that demonstrate the performance of the methods.