Surface fluorinated epoxy resin for high voltage DC application

Charge accumulation under high voltage DC is a major concern in the transmission system as its presence distorts the local electric field. By performing chemical treatment on polymeric insulation via fluorination process, the charge transport characteristics of the material can be modified. In doing so, excellent surface properties of fluoropolymers can be attained without compromising the bulk properties of the original polymeric insulation. The change in chemical components at the surface of polymeric insulation should lead to a corresponding change in electrical properties at the surface and so suppress charge accumulation. In this paper, epoxy resin samples were formulated and treated with various surface fluorinating conditions. The samples then were characterised by scanning electron microscope (SEM), Raman spectroscopy and DC surface conductivity measurements. The surface potential decay measurement was performed and the result shows that there is a significant change in surface potential decay measurement with the introduction of surface fluorinated layer. The pulsed electroacoustic (PEA) measurement was used to further explain the decay mechanisms responsible for the observed phenomena. Surface DC flashover test using a pair of finger electrodes had also been conducted. It has been found that the introduction of fluorinated surface layer on epoxy resins plays an important role in improving the surface dielectric properties as apparent from the experimental results.