Analysis of Insulator Leakage Current Based on Hilbert-Huang Transformation

Hilbert-Huang Transform and Hilbert spectrum are introduced in this paper to analysis the insulator leakage current and pollution flashover mechanism. Firstly a method based on characteristics of insulator leakage current is put forward to solve the end swing phenomena exist in Empirical Mode Decomposition (EMD).The validity of the method is validated by experiment. And then the improved EMD is used in the denoise of insulator leakage current. Comparison of EMD and wavelets in the effect of denoise quality showed the superiority of the former. Finally Hilbert marginal spectrum and marginal energy spectrum are used to analysis the insulator leakage current under different relative humidity, salt conductivity and equivalent salt deposit density. Based on Hilbert spectrum analysis of discharge process, the average amplitude, energy of fundamental harmonic and ratio of the third harmonic energy to the fundamental harmonic energy are extracted as eigenvectors for the prevention of flashover.