Recurrent Plot Analysis of Leakage Current in Dynamic Drop Test for Hydrophobicity Evaluation of Silicone Rubber Insulator

In order to reduce electrical accidents caused by aging of polymer insulators, hydrophobicity evaluation is one of the essential methods to monitor the practical performance of insulators. This paper presents recurrent plot (RP) analysis of leakage current (LC) to evaluate the hydrophobicity of the silicone rubber insulator. Experiments were carried out according to the dynamic drop test method. Dynamic behaviors of water droplets and the induced discharge phenomena were captured by using a high-speed camera fixed vertically to the specimen surface. LC was measured and extended to m-dimensional phase space by using a phase-space reconstructed method. The RP of LC was obtained to reflect the underlying mechanism of surface discharges in relation to the insulator hydrophobicity. The results indicate that the RP technique can give a visual method for the hydrophobicity evaluation. The increasing tendency in RP indicators can reveal the decrease of hydrophobicity.