Degradation of thermoplastic elastomeric nanocomposite materials exposed to corona discharge and impact on hydrophobic properties

The design development and construction of outdoor insulator are based on the requirement to prevent completely-wetted zones. However, insulating materials such as polymer that used in high voltage technology usually exposed to corona discharge. Long term of corona discharge reduce the hydrophobicity and cause the degradation of the insulators. It may increase the leakage current over insulators which may lead to increasingly severe arcing activity and proceed to flashover. Thermoplastic Elastomer (TPE), a type of rubber-like material is believed to surpass other materials like Silicon Rubber (SIR) and Ethylene Propylene (EP) due to its excellent hydrophobicity characteristic which account for a wide range of insulation applications. This paper presents the experimental results of corona aging studies on hydrophobic properties for different type of TPE nanocomposites. Three nanofillers, i.e. Montmorillonites (MMT), Silicon Dioxide (SiD), and Aluminum Oxide (AO) were used to study the effects. Pointed-plane electrode geometry has been used to create the corona on the samples. The changes of hydrophobic properties of these materials were determined by the contact angle measurement technique. Results attained confirm that the existence of nanofillers in TPE nanocomposite materials affect the hydrophobic characteristic of these insulators before and after the corona discharge exposure in different prospective.