A novel technique for estimating harmonic and inter-harmonic frequencies in power system signals

This paper proposes a modified Prony technique for estimating the frequencies in electric power circuit signals. It is based on the factoring of the polynomial formed from the autoregressive parameters representing the signal into second degree polynomials. The coefficients of the second degree polynomials are estimated by a Newton method. The coefficients are directly related to the modal frequencies of the signal. Unlike Prony´s method, there is no need to determine the roots of any polynomial. The proposed technique also allows the decomposition of the signal into Prony components. It has been applied to determine the frequencies of a synthetic signal.