UHF technique for identification of discharges initiated by liquid droplet in epoxy nanocomposite insulation material under ac voltages

Abstract

In this work, an attempt has been made to understand the feasibility of using a ultrahigh frequency (UHF) technique for identification of any corona discharge/ arcing in insulating material due to water droplets. The sensors of broadband type are useful for the identification of such discharges. It is realized that corona discharges/arcing initiated by liquid droplet radiates UHF signals in the entire bandwidth up to 2 GHz. The frequency content of the UHF signal generated due to corona/arcing is not much varied in epoxy nanocomposites with different weight percentage of clay content. The exfoliated/intercalated properties were analysed through TEM studies. It is realized that corona initiated discharges are of intermittent process. It is observed that the permittivity and tan(δ) reduces with increase in percentage of clay in epoxy nanocomposite material up to 3 wt%. The hydrophobicity of the material is characterized through contact angle measurement. It is realized that low weight percentage of nanoclay content in epoxy resin reduces the surface carbonization due to arcing.

Study of the behavior of AC discharges of water drops on both conducting and dielectric solid surfaces

“…It is well known in general that when the drop is placed in a high electric field zone, corona discharge occurs at the edge of the water drop [19,20]. The same behavior can be clearly observed for one or two sessile drops connected to electrodes, and when both electrodes are stressed with ac voltage.…”

Wet conductor surfaces and the onset of corona discharges

“…Dynamic behaviour was also evaluated on the water stream from the bottom of conductors [7][8]. As a result of the development of composite insulators, considerably more work has been published on water droplet behaviour on insulation surfaces [10][11][12][13][14][15][16][17][18][19].…”

Understanding the discharge activity across GFRP material due to salt deposit under transient voltages by adopting OES and LIBS technique

“…To understand the surface discharge activity in GFRP material, the quasi-uniform electric field gap consists of two angular electrode tip cut for 45˚ (with edges smooth) placed on 3 mm thick GFRP material, as shown in Figure 2. The electrode configuration used in the present study is as per standard IEC-60112 [26,27]. The electrodes used are of stainless steel material, and are separated by a gap distance of 10 mm.…”