Study on the Hydrophobicity of HTV SIR Treated by Different Corona Intensity

HTV SIR has been widely used as the outer insulation of composite insulators, which mainly depends on the unique hydrophobicity of HTV SIR. In this paper, the influence of corona intensity on the hydrophobicity of HTV SIR was investigated. The HTV SIR samples were aged under five levels of voltage. The hydrophobicity loss and recovery were evaluated by static contact angle. Experiments results show that the hydrophobicity won´t lose until the corona intensity gets the corona onset electric field. Once the corona discharge occurs, the hydrophobicity loss will be accelerated with the enhancement of corona intensity. As for the hydrophobicity recovery, when the corona duration is shorter, the hydrophobicity recovery quickens up with the increasing of corona intensity. The hydrophbicity recovery, however, slows down by the enhancement of corona intensity when the corona duration is prolonged to a certain value. Meanwhile, it is noticed that under some aging condition, the hydrophobicity of HTV SIR can´t get recovery even if the storage time is enough long. So it is assumed that there is no affirmatory correlation between the hydrophobicity recovery speed and the corona intensity. Further analysis identify that the microstructure and chemical composition play an important role in the hydrophobicity recovery progress.