Power System Interharmonics Monitoring Based on Wavelet Transform and AR Model

This paper proposes a method of monitoring and analyzing interharmonics in power system based on wavelet transform and AR model. First, utilizes wavelet denoising method of sqtwolog soft threshold to eliminate the high-frequency noise of sampled signals containing interharmonics signal. Then, the parameters of interharmonics are identified by using the Burg arithmetic of AR model, and the wavelet transform and AR model are applied to virtual instrument by using the MATLAB script node in LabVIEW. Final Prediction Error is used to select the most appropriate order of AR model. Some essential issues, such as the spectrum distinguishing ability and the anti-noise ability of the algorithm, are researched. The Simulation results show that by using the proposed method, the interharmonics near the integer harmonics can be detected accurately with higher anti-noise ability.