Insulator Leakage Current Data Analysis Based On The Improved Of EMD Algorithm

High-voltage transmission line insulator flashover occurs often lead to large long power outages caused great damage to the national economy, so the electric transmission line insulator flashover occurred significance of monitoring and prevention, while the insulator flashover based on monitoring and prevention leakage current work is on data analysis. In this paper, we use the improved EMD to decompose the leakage current data, and use wavelet threshold denoising method to denoise these thresholds, then get the time spectrum and the marginal power spectrum by Hilbert transform, then use tme-frequency entropy, the leakage current effective amplitude and the ratio between third harmonic and fundamental power as characteristic quantities to analyze data at last.Firstly the end swing phenomena and modal mixing existing in Empirical Mode Decomposition (EMD) were solved by the method of Mirroring closed and differential operational respectively. The superiority of the improved EMD method was validated by the experiment. Secondly the threshold method in wavelet analysis was used to denoise the data of the leakage current. The appropriate threshold which was acquired through the colander separated the noise signal from the EMD decomposed valid signals.After the experimental validation, A valid data offered to the analysis of Hilbert spectrum and Hilbert marginal energy spectrum. The Hilbert marginal energy and the frequency spectrum was obtained by the Hilbert-Huang changing the leakage current data which has decomposed by EMD. The feature in different stages of leakage current was analyzed by the Hilbert spectrum and Hilbert marginal energy spectrum . The time-frequency entropy was introduced in the article as a feature vector. According to the feature of the insulator contamination flashover, the various stages of leakage current can be divided into the non-forecast area, the forecast area, the dangerous area and the flashover stage in the experiment.In this paper, the time-frequency entropy, the amplitude of leakage current and the ratio of the third harmonic to the fundamental harmonic were treated as characteristics of the leakage current during flashover. Finally, the paper provides parameters of the feature of leakage current to prevent insulator flashover.