Understanding surface discharge activity with epoxy silicon carbide nanocomposites

Abstract

Surface discharge inception voltage (SDIV) with epoxy silicon carbide nanocomposite material in LN 2 medium is about three times higher than that in air. Under AC voltage that SDIV increases with increase in wt% of silicon carbide (SIC) material in epoxy nanocomposites. Dielectric measurements indicates an increase in temperature of the specimen and the weight percentage of SIC filler in epoxy resin increases the permittivity of the material. Also, irrespective of percentage of SiC in epoxy resin, the tan(d) reduces with increase in frequency and the converse at room temperature. The UHF signal measured during surface discharge activity in air/LN 2 medium has frequency content in the range of 0.5-1.5 GHz. The charge decay characteristics of epoxy SiC nanocomposites indicate the deposited charge is less and the charge decay time reduces with increase in wt% of SiC in epoxy resin. The surface roughness caused due to surface discharge activity is high under negative DC voltage compared with positive DC/AC voltage. The phase resolved partial discharge (PRPD) analysis indicates discharges occur at the near peak of the AC voltage on inception of surface discharge and at higher stress it appears at the rising portion of AC voltage.

Study on water droplet initiated discharges and charge trap characteristics of laser textured silicone rubber nanocomposites

“…Sarathi et al, have previously indicated that the decay rate of surface potential is nearly the same with epoxy silicon carbide nanocomposites. [ 29 ] The charge accumulated on an insulating material can dissipate in three different methods: (a) along the surface of the specimen, (b) into the bulk of the specimen, and (c) into the surrounding ambience. [ 30 ] The dissipation along the surface is mainly affected by surface resistivity of the material.…”

Surface Discharges and Flashover Voltages in Nanocomposite XLPE Samples

“…The aforementioned interpretations seem to be in agreement with [9], where it was reported that there can be surface modifications of the nanocomposites and of the nature of the interface in the region around the nanofillers. These views are also shared in [10,11]. It is true that the present research was carried out using AC voltages whereas it is intended that the tested materials will be used for DC transmission.…”

Understanding the dielectric and mechanical properties of self‐passivated Al–epoxy nanocomposites

“…The voltage at which UHF sensor generates UHF signal, on the application of voltage, is defined as CIV [16,20]. It is observed from Fig.…”

“…Also, the water droplet on insulation material formed due to rain or fog condensation during power apparatus operation may lead to the formation of the corona and further leads to surface discharge activity due to enhancement in the local field. Sarathi et al [16] have studied water droplet initiated corona discharges under different voltage profiles through radiated UHF signals. The discharges caused due to water droplet reduce the hydrophobicity of the material and formation of carbonised marking on the surface of the material, which further reduce the lifetime and cause the failure of insulation structure.…”