Application of bi-spectrum analysis for icing insulator leakage current

A new method based on bi-spectrum analysis was presented for insulator leakage current analysis. By discussing the bi-spectrum theory, the characteristics of icing insulator leakage current signal were analyzed. It obtained the contour value figure and the 3D figure from bi-spectrum. Results show that, with the development of insulator discharge, the quadratic phase coupling´s scope is getting smaller. The highest peak of 3D bi-spectrum increases obviously. Between two adjacent periods, the highest peak value of 3D bi-spectrum increases about 3 or 4 magnitudes. It can provide the new characteristic for leakage current analysis, which is beneficial to establish icing insulator flashover warning system.