Acoustic characteristic for hydrophobicity evaluation of silicone rubber insulator in smart grid

Hydrophobicity is a prominent characteristic of silicone rubber for polymer insulators. The accurate evaluation on the insulator hydrophobicity is increasingly required for the long-term performance of outdoor insulators in the smart grid. In this paper, based on dynamic dropping test (DDT), acoustic characteristic of surface discharges generated by the dynamic behavior of water droplet was investigated to evaluate the hydrophobic properties of silicone rubber insulator at different ageing levels. The specimens were prepared by using the method of corona degradation and determined by contact angle (CA). It is found that characteristic of discharge sound changing with the decrease of CA. Therefore, the results obtained indicate that the acoustic characteristic of discharge in DDT method is sensitive to the hydrophobic properties, which can be applied as a non-contact method for hydrophobicity evaluation of silicone rubber insulators.