Interharmonics analysis based on windowed interpolation and prony algorithm

Detecting interharmonics in power system for flicker troubshooting is highly desirable. Whereas these interharmonics are close to harmonic or fundamental component, it is always swamped by the main-lobe of harmonic nearby if the harmonic amplitude is much bigger than interharmonic amplitude, and vice versa. In this paper, a double-stage algorithm is proposed based on the windowed interpolation and the Prony method to overcome this problem. The interpolation method calculates most parts of harmonics and identifies the frequency interval in which two adjacent components are located, and then the Prony algorithm is used to compute these two adjacent components. Matlab simulation shows that two adjacent components can be detected with acceptable precision and the accuracy of other harmonic components enjoy the same as the interpolation algorithm.