Improved Prony Method for High-Frequency-Resolution Harmonic and Interharmonic Analysis

An improved Prony method for high-frequency-resolution harmonic and interharmonic analysis of power system is proposed in this paper. The proposed method combines the merits of Prony methods and subspace methods, and the eigenvector corresponding to the minimum eigen value is used to obtain the Prony coefficients. It also exploits the symmetry property of Prony coefficients, and proposes a method to construct the autocorrelation matrix whose size is only half of the original. The determination of the estimation order is also analyzed. The proposed method is compared with some of harmonic/interharmonic analysis methods with high frequency resolution, including the traditional Prony method, Min-norm method, and ESPRIT method. Theoretical analysis and numerical results show that the proposed method can perform accurate high-frequency-resolution harmonic/interharmonic analysis of power system signals.