Using chaotic features of leakage current for monitoring dynamic behavior of surface discharges on an ice-covered insulator

Based on AC flashover tests on an ice-covered insulator, leakage current (LC) was measured to check the chaotic features through estimation of the largest Lyapunov exponent. Based on the embedding space theory and phase space reconstruction method, the LC attractor phase portrait and related correlation dimension were obtained in relation with the insulator surface performance. It was found that the largest Lyapunov exponents are all positive demonstrating that LC has chaotic features. The variation in chaos attractors can graphically indicate an increasing regularity in the surface discharges. The correlation dimension shows a decreasing tendency with the development of arcing discharges, which reveals a decreasing complexity in the surface discharges, especially just prior to the flashover occurrence. Therefore, chaotic features of LC are sensitive to dynamic discharge behavior on ice-covered insulators, which can be applied as a monitoring method for pre-warning flashover occurrence of outdoor insulators under icing conditions.