Abstract
This study examines the influence of various electrical parameters on the volume resistivity of the Viton fluoroelastomer. The transient current, the temperature dependence of volume resistivity, the voltage dependence of resistivity, and the surface morphology of Viton insulators are investigated for new and aged specimens. An accelerated aging process has been employed in order to simulate the natural aging of insulators in service. A detailed comparison between the new and aged samples is presented. The transient effect, which is a challenge to the resistivity measurement of insulators, has been investigated. The first 60 s of the resistivity measurement test showed a significant influence from the transient effect and should be excluded from the data. The volume resistivity of both new and aged samples decreased when the temperature increased. However, the resistivity of the aged sample was lower than the new one at all tested temperatures. When the temperature increased from 35 to 190 °C, resistivity decreased from 4.77 × 1010 to 6.99 × 108 Ω-cm for the new sample and from 2.6 × 1010 to 6.68 × 108 Ω-cm for the aged sample under 500 V. Additionally, the results from this study showed that the volume resistivity is inversely proportional to the applied voltage. Finally, scanning electron microscope (SEM) micrographs/images allowed us to closely examine the surface morphology of new and aged Viton samples. The surface of aged samples has been recognized with higher surface roughness and more significant surface cracks leading to poor performance under high voltage applications.
Highlights
In the 21st century, for outdoor insulation applications with the need for hightemperature resistance and strength, polymeric insulators have replaced ceramic materials
In order to ascertain the electrical properties of the insulating Viton, in this study, we investigated the effects of various parameters, e.g., transient effect, the temperature dependence of volume resistivity, and the voltage dependence of resistivity and surface morphology on the resistivity measurement using commercially available Viton specimens before and after the accelerated thermal aging process
It was clear from the graphs that the electric resistivity of the aged Viton sample was found to be lower compared to the new Viton sample
Summary
In the 21st century, for outdoor insulation applications with the need for hightemperature resistance and strength, polymeric insulators have replaced ceramic materials. Long operational hours at a high temperature constantly affect the polymeric materials This is commonly known as thermal aging, which can drastically change the electrical properties and the chemical structure of the polymer. When a large voltage is applied to a polymeric sample, the small amount of current flowing through the sample can be measured in order to obtain the resistance of the sample as a traditional accepted technique In order to ascertain the electrical properties of the insulating Viton, in this study, we investigated the effects of various parameters, e.g., transient effect, the temperature dependence of volume resistivity, and the voltage dependence of resistivity and surface morphology on the resistivity measurement using commercially available Viton specimens before and after the accelerated thermal aging process
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